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   69篇
  免费   8篇
  2020年   6篇
  2019年   5篇
  2018年   2篇
  2017年   5篇
  2016年   3篇
  2015年   3篇
  2014年   3篇
  2013年   9篇
  2012年   5篇
  2010年   2篇
  2008年   1篇
  2007年   2篇
  2004年   1篇
  2003年   4篇
  2002年   4篇
  2001年   2篇
  2000年   2篇
  1999年   1篇
  1998年   2篇
  1997年   1篇
  1996年   2篇
  1995年   4篇
  1994年   1篇
  1993年   1篇
  1992年   1篇
  1988年   1篇
  1974年   2篇
  1973年   1篇
  1971年   1篇
排序方式: 共有77条查询结果,搜索用时 593 毫秒
11.
12.
Standard nomenclature in Supreme Court literature contrasts the "old Court" and the "new Court" (or, sometimes, the "modern Court"). By most accounts, the dividing line between the two falls during the years 1937–1940, when the nation witnessed a judicial and constitutional revolution. The proverbial "irresistible force" (in the form of President Franklin Roosevelt's New Deal program to cope with the Great Depression) met the "immovable object" (in the guise of the Supreme Court under the leadership of Chief Justice Charles Evans Hughes that, for a short time, stymied many of the President's initiatives). The result was Roosevelt's audacious assault on the Court through the Court-packing plan and the hasty change of mind by Hughes and Justice Owen J. Roberts that gave Roosevelt the five sure votes he needed so that his agenda could receive the constitutional stamp of approval. This flip-flop was promptly followed by the Court's adoption of a new agenda for itself, one that elevated civil liberties into a preferred position in the hierarchy of constitutional values and demoted property interests, which heretofore had been accorded heightened judicial protection.  相似文献   
13.
14.
A Sensitive High Resolution Ion MicroProbe (SHRIMP II) has been used to make high spatial resolution in situ micro-analyses of oxygen isotopes in fish otoliths, and teeth from fossil herbivores and a Neanderthal. Large intra-tooth variations in the oxygen isotopic composition (up to 9‰) were observed in the enamel of herbivores from the Neanderthal fossil site of Payre, consistent with preservation of seasonal cyclicity. The range of isotopic compositions observed in Neanderthal tooth enamel was much smaller (∼3‰), possibly the result of a longer enamel maturation time averaging out variability. An archaeological otolith from a Preceramic site in Northern Peru exhibited marked changes in δ18O over life, due either to the fish occasionally migrating from the sea to a lower salinity habitat, or to short-lived rises in sea water temperature. A fish otolith from Australia's Willandra Lakes World Heritage Area showed clear seasonal variations, but also a general trend towards isotopically heavier and more saline water, as indicated by higher δ18O and Sr/Ca values resulting from increased evaporation. The results of these case studies are compared to results of oxygen isotope analysis using more conventional methods and demonstrate the ability of the SHRIMP II to provide precise high spatial resolution in-situ oxygen isotope analyses of a variety of biogenic materials. This approach has major advantages over conventional methods. It can provide rapid, micro-scale isotopic analyses of sub-permil precision without the need for chemical preparation of the sample.  相似文献   
15.
While boat and ship graves are known from across northern Europe, and are particularly associated with the Viking Age, only seven examples of such monuments have been excavated in Iceland. Furthermore, no shipwrecks are known dating from this period in Iceland, and examples of boat timbers preserved by waterlogging are very rare. As such, the mineralized wood remains from these burials comprise the vast majority of direct archaeological evidence currently available for the boats used in daily life in early Iceland. This paper uses taxonomic identification of mineralized wood remains from the Icelandic boat graves, along with comparative data from Europe and Scandinavia, to discuss boat construction and repair in early Iceland, including the possibilities of driftwood utilization and the importation of boats from Norway. The economic and social significance of the practice of boat burial in Iceland is also explored, with regard to the importance of boats as transport and the limited availability of wood suitable for boat construction and repair.  相似文献   
16.
Hunting is one of the areas of human activity that sees the most significant changes in the period from 40 000–35 000 BP in Europe. In this respect, the Aurignacian technocomplex shows technical innovations, notably with the fabrication of split-based points (SBP) in antler and the mass production of bladelets, arguably to serve as weapon armatures. Yet, little experiment work has been dedicated to this question. To begin to fill this gap, we have designed an experimental program devoted to testing and assessing the design, manufacture and use of Aurignacian weaponry.  相似文献   
17.
18.
19.
An analysis of Forest Service-related legislative activity found that increasingly Congress is becoming involved in agency activities and decisionmaking. Congress's growing scrutiny and management of the Forest Service is indicated by rising trends in requests for agency testimony at congressional hearings, in the number of Forest Service-related bills and amendments introduced in Congress, and in the amount of Forest Service-related legislation enacted. Anecdotal evidence of direct political pressure imposed upon agency personnel by congressional members also indicates that much congressional influence occurs outside of these legislative activities. An examination of activities such as these and directives attached to annual appropriation bills also shows that not all congressional actions are productive in fostering positive agency change. The results of this study indicate the likelihood that Congress has been playing a major role in instigating change within the agency.  相似文献   
20.
Interest groups involved in the Forest Service's 1990 Resources Planning Act (RPA) forest planning process and representatives from accredited forestry schools were surveyed via a written questionnaire on their perceptions of change within the Forest Service since 1976. Respondents felt that the agency had changed, particularly during the late 1980s and early 1990s. Consumptive users perceived the change to be negative, while non-consumptive user groups and forestry schools felt it was somewhat positive, although they still felt the Forest Service had much further to go in this direction before achieving these groups' desired priorities for National Forest management. These results indicate that the agency is undergoing a net shift in direction towards increased emphasis on non-commodity forest uses. In general, external forces, such as Congress and the courts, were seen as having a greater impact on agency change than were sources of change within the agency itself. Forestry schools agreed most often with non-consumptive users, indicating that these programs may be undergoing a change away from their traditional focus on timber production. In addition to providing valuable insights on the subject of change in the Forest Service, these survey results locate areas of agreement and disagreement, and provide valuable feedback to the agency regarding its constituent groups' views about its performance in managing the National Forests.  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