首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3270篇
  免费   137篇
  2020年   33篇
  2019年   68篇
  2018年   76篇
  2017年   111篇
  2016年   96篇
  2015年   82篇
  2014年   81篇
  2013年   1199篇
  2012年   64篇
  2011年   81篇
  2010年   60篇
  2009年   73篇
  2008年   51篇
  2007年   73篇
  2006年   47篇
  2005年   41篇
  2004年   37篇
  2003年   37篇
  2002年   49篇
  2001年   39篇
  2000年   42篇
  1999年   34篇
  1998年   45篇
  1997年   53篇
  1996年   27篇
  1995年   29篇
  1994年   19篇
  1993年   25篇
  1992年   26篇
  1991年   19篇
  1990年   26篇
  1989年   16篇
  1988年   29篇
  1987年   29篇
  1986年   24篇
  1985年   38篇
  1984年   42篇
  1983年   44篇
  1982年   45篇
  1981年   35篇
  1980年   35篇
  1979年   43篇
  1978年   42篇
  1977年   42篇
  1976年   33篇
  1975年   32篇
  1974年   13篇
  1973年   23篇
  1972年   17篇
  1971年   13篇
排序方式: 共有3407条查询结果,搜索用时 643 毫秒
81.
82.
83.
Cultural resource management (CRM) work accounts for most of the archaeology conducted in the United States. A diverse and somewhat fragmented field, CRM has nonetheless achieved a degree of institutional and organizational maturity. CRM archaeology has produced important contributions to archaeological methodology and has established and refined knowledge of regional cultural-historical sequences and settlement and subsistence patterns. The current florescence of historical archaeology is attributable to CRM. Yet the maintenance of high quality in CRM is a pervasive and enduring problem. Academic institutions need to reestablish alliances with the CRM community. The future viability of CRM archaeology depends on factors both internal and external to the discipline: regulatory and statutory “reform,” agency funding levels, looting and other destructive forces, and Native American and other public involvement.  相似文献   
84.
Abstract. In postcommunist politics many of the ‘new national right’ political formations in Eastern Europe and the former Soviet Union have joined forces with the communist successor parties. Such a combination is, on the surface, a baffling mixture; how is it possible that two fundamentally different ideological approaches (nationalism and internationalist socialism) can coexist and actively cooperate to form such a potent political force? What are the conditions under which such political cooperation emerges? This article attempts to answer the above questions by, first, empirically testing the effects of several factors which might explain postcommunist–nationalist political cooperation. Second, the quantitative analysis is buttressed with a comparison of the Hungarian and Russian cases. The analysis indicates that the most important variable associated with the emergence of postcommunist–nationalist political cooperation is the effect of previous regime type.  相似文献   
85.
We develop a new conceptual approach to locating inspection stations for hazardous vehicles, prevention, and compare it to the previous, punitive, philosophy of the flow-capturing location model. We implement this preventive protection philosophy with a new mixed integer program that maximizes hazard avoidance by locating a number of inspection stations to detect and remove hazardous vehicles as early in their trips as possible. We test the model's performance and analyze the spatial characteristics of solutions simulating several potential applications. Our computations demonstrate that a relaxed integer-linear program is overly demanding computationally and that a simple greedy heuristic lacks robustness. We suggest further approaches to developing more powerful and efficient solution methods.  相似文献   
86.
ABSTRACT. This paper uses new estimates of metropolitan factor demand and output supply functions to study how federal, state, and local fiscal policies affect metropolitan economies. We illustrate our work with findings for ten metropolitan areas in five states for changes in state corporate income taxes, local property taxes, the federal corporate income tax, an investment tax credit, interest rates, public capital stocks, output prices, and tax and regulatory policies affecting gross wages. It is clear from these simulations that a policy that is nominally the same everywhere will have repercussions that vary widely across regions and cities.  相似文献   
87.
This study examined landcover change during 1940–1988 in two contiguous landscapes of approximately 12,400 hectares in central Ohio, USA: an inertial till plain area and a more dynamic moraine area. Agriculture dominated both landscapes throughout, however, the cover of natural vegetation and urban-suburban development increased over time on the moraine while natural vegetation decreased and agriculture increased on the till plain. Markov process models for landcover change were constructed for three 14–17-year time intervals and for the entire forty-eight-year study period. Probabilities of self-replacement for agricultural lands (0.91–0.97) were higher and those for forests (0.54–0.65) lower than those reported for other landscapes. Predictions of landcover percentages for fifty years in the future were made using Markov process models derived from actual cover changes in 1940–1957, 1971–1988, and 1940–1988. All three models produced similar predictions for the inertial till plain area. In contrast, the three models' predictions differed considerably for the moraine area. Only the 1971–1988 transition matrix was sensitive to increases in urbanization and reforestation which began on the moraine in the 1970s. These results indicate that reliance on lengthy study intervals and net rates of change can obscure spatial and temporal patterns of landcover change that are caused by natural and socioeconomic factors operating on shorter time scales.  相似文献   
88.
ABSTRACT. In this paper a gravity model is formulated to model a hospital patient flow system. Both spatial and nonspatial measures of separation are used to estimate the model. Travel time was found to provide improved fits over linear distance in modeling patient flow behavior. Transformations of travel time (square root and log) were found to improve model performance further. Model diagnostics suggested additional spatial separation measurw, separation measure parameters demonstrated stability over time. The model is used to forecast the effects of health care financing reform and hospital closure on patient flows in an urban hospital market. Universal health coverage was found to dramatically improve access to hospital services for lower income patient populations. Hospitals at risk for closure were forecast to receive increased patient flows. Medical school hospitals are expected to lose patients after implementation of health reform, with important implications for graduate medical education. Hospital closures were shown to have negative effects on access to services in poor neighborhoods, but relatively little effect on access in the system as a whole.  相似文献   
89.
Book Reviews     
Ken Booth and Steve Smith (eds), International Relations Theory Today, Cambridge: Polity Press, 1995. xii + 367pp. $39.95 (paper).

Christine Sylvester, Feminist Theory and International Relations in a Postmodern Era. Cambridge: Cambridge University Press, 1994. xi + 265pp. $47.50 (paper).

Stephanie Lawson (ed.), The New Agenda for Global Security: Cooperating for Peace and Beyond. St. Leonards: Allen & Unwin/Department of International Relations, RSPAS, Australian National University, 1995. xi + 217pp. $24.95.

Anne O. Krueger, Economic Policies at Cross‐Purposes: The United States and Developing Countries. Washington, DC: Brookings Institution, 1993. xii + 253pp. $US36.95 (cloth).

Robert L. Paarlberg, Leadership Abroad Begins at Home: U.S. Foreign Economic Policy After the Cold War. Washington, DC: Brookings Institution, 1995. xxv + 115pp. $US28.95 (cloth); $US10.95 (paper).

Tony Brenton, The Greening of Machiavelli: The Evolution of International Environmental Politics. London: Royal Institute of International Affairs/Earthscan, 1994. xvii + 282pp. $UK14.95 (paper).

John Charmley, Churchill's Grand Alliance: The Anglo‐American Special Relationship, 1940–1957. London: Hodder & Stoughton, 1995. xv + 427pp. $55.00 (cloth).

Victor A. Kremenyuk, Conflicts In and Around Russia. Nation‐Building in Difficult Times. Westport: Greenwood Press, 1994. xiv + 159pp. $US49.95 (cloth).

Alexander Johnston, Sipho Shezi and Gavin Bradshaw (eds), Constitution‐making in the New South Africa. London and New York: Leicester University Press, 1993. viii + 272pp. $UK 39.50.

Ramesh Thakur, The Politics and Economics of India's Foreign Policy. London: Hurst and Company; New York: St. Martin's Press, 1994. xi + 306pp. No price given.

Francis Seow, To Catch a Tartar: A Dissident in Lee Kuan Yew's Prison (with a foreword by C.V. Devan Nair). Yale Southeast Asia Studies Monograph 42, New Haven: Yale Centre for International and Area Studies, 1994. xxxiii + 293pp. $50.00 (paper).

Brij Lal, Robert Kiste and Kerry Howe (eds), The Tides of History: The Pacific Islands in the 20th Century. St Leonards: Allen & Unwin, 1994. xviii + 475pp. $34.95 (paper).

LaMond Tullis, Unintended Consequences—Illegal Drugs and Drug Policies in Nine Countries. Boulder, CO: Lynne Rienner, 1995. ix + 229pp. $US42.00 (cloth).

The United Nations and Cambodia 1991–1995, The United Nations Blue Books Series, Vol. II. New York: Department of Public Information, United Nations, 1995. 352pp. $US29.95 (paper).

‘Atu Emberson‐Bain (ed.), Sustainable Development or Malignant Growth? Perspectives of Pacific Island Women. Suva, Fiji: Marama Publications, 1994. 290pp. No price given.

Payam Akhavan and Robert Howse (eds), Yugoslavia, the Former and Future: Reflections by Scholars front the Region. Washington, DC and Geneva: The Brookings Institution and The United Nations Research Institute for Social Development, 1995. xxviii + 188pp. $US32.95 (cloth) $US 12.95 (paper).

David Camroux, ‘Looking East’ . . . and Inwards: Internal Factors in Malaysian Foreign Relations during the Mahathir Era 1981–1994. Australia‐Asia Papers No. 72. Griffith University: Centre for the Study of Australia‐Asia Relations, 1994. iii + 62pp. $10.00.  相似文献   

90.
This article is a contribution to the debate on the nature of the modern Labor Party and a commentary on the extensive literature which the debate has produced (see Warhurst 1994). An important element in this literature is the argument that the modern Labor Party, led by Bob Hawke and Paul Keating, is no longer the party it once was, but is fundamentally different in its policies, and that indeed in its very nature it is alien to Labor traditions (Maddox 1989; Jaensch 1989; Beilharz 1994). This line of argument has been called, by Rick Kuhn, the discontinuity thesis, and is now known as such (Kuhn 1992). Along with others, I am not convinced by this thesis but would rather emphasise the continuities in Labor experience. Like Hugh Emy I believe that 'The contrast between the two [Whitlam and Hawke] has been overdrawn'. (Emy 1993, p. 20)  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号