全文获取类型
收费全文 | 7861篇 |
免费 | 144篇 |
专业分类
8005篇 |
出版年
2020年 | 128篇 |
2019年 | 189篇 |
2018年 | 232篇 |
2017年 | 210篇 |
2016年 | 280篇 |
2015年 | 186篇 |
2014年 | 172篇 |
2013年 | 1965篇 |
2012年 | 230篇 |
2011年 | 260篇 |
2010年 | 244篇 |
2009年 | 241篇 |
2008年 | 203篇 |
2007年 | 211篇 |
2006年 | 180篇 |
2005年 | 113篇 |
2004年 | 102篇 |
2003年 | 105篇 |
2002年 | 120篇 |
2001年 | 151篇 |
2000年 | 105篇 |
1999年 | 124篇 |
1998年 | 99篇 |
1997年 | 87篇 |
1996年 | 85篇 |
1995年 | 72篇 |
1994年 | 61篇 |
1993年 | 73篇 |
1992年 | 73篇 |
1991年 | 66篇 |
1990年 | 67篇 |
1989年 | 60篇 |
1988年 | 58篇 |
1987年 | 69篇 |
1986年 | 68篇 |
1985年 | 73篇 |
1984年 | 86篇 |
1983年 | 90篇 |
1982年 | 75篇 |
1981年 | 74篇 |
1980年 | 76篇 |
1979年 | 63篇 |
1978年 | 68篇 |
1977年 | 71篇 |
1976年 | 65篇 |
1975年 | 73篇 |
1974年 | 48篇 |
1973年 | 46篇 |
1972年 | 47篇 |
1971年 | 44篇 |
排序方式: 共有8005条查询结果,搜索用时 0 毫秒
991.
Robert J. Losey Vladimir I. Bazaliiskii Sandra Garvie-Lok Mietje Germonpr Jennifer A. Leonard Andrew L. Allen M. Anne Katzenberg Mikhail V. Sablin 《Journal of Anthropological Archaeology》2011,30(2):174-189
Interpretations of dog burials made by ancient foraging groups have tended to be based upon our own relationships with such animals and modern western cosmological and ontological concepts. Osteological studies of early dogs often focus only on issues of taxonomy, and as a result very little is known about these animals’ life histories. Eastern Siberia has produced many Holocene dog burials, but these are typically not well described and the explanatory frameworks provided for them are very underdeveloped. Here we examine in detail two Cis-Baikal canid burials, one of a wolf and the other a dog, both in large Middle Holocene hunter-gatherer cemeteries. We link the mortuary treatment of these animals to other cultural practices, particularly the treatment of the human dead, and broader patterns in Northern human-animal relationships. This interpretive model is combined with detailed osteobiographies for the canids and contextual information for these and other dogs and wolves from Middle Holocene Cis-Baikal. It is argued that canids here were understood and treated in a variety of ways. We suggest that some animals with unique histories were known as distinct persons with ‘souls’ and because of this at death required mortuary rites similar to those of their human counterparts. 相似文献
992.
Managing agricultural risk, or variance in annual production, is a priority for farmers and herders. This article reviews the ethnographic and historical literature on agricultural risk management and identifies diversification and intensification as two distinct approaches to managing risk. Quantitative analysis of plant and animal remains from archaeological sites produces robust datasets that can be used to test predictions of risk management models related to diversification and intensification strategies. I present a variety of established and novel paleoethnobotanical and zooarchaeological measures that have implications for risk management and argue that multiple lines of evidence are needed to identify risk-management practices from archaeological remains. The article concludes with a case study of the multiperiod urban center of Gordion in central Turkey, where quantitative analysis of plant and animal remains demonstrates diachronic changes in agricultural risk management over 3000 years of occupation. 相似文献
993.
Michèle M. Wollstonecroft 《Archaeological and Anthropological Sciences》2011,3(1):141-150
While it is generally agreed that food processing has had a role in human evolution, the specific ways that is has affected
our evolution are not well understood. Using a Niche Construction Theory (NCT) perspective, coupled with methodologies borrowed
from “post-harvest” research in the plant sciences, this paper investigates the means and mechanism by which food processing
is of evolutionary consequence. The central tenet of NCT is that organisms have an active role in their own evolution through
reciprocal interactions with their environments; niche construction is understood to occur when organisms initiate long-term
changes to their environments that modify the selection pressures on themselves and their descendants (and on other organisms
in the environment). Humans and our hominin ancestors are considered to be the ultimate niche constructors due to our ability
to modify selection pressures through diverse culturally generated and transmitted cultural means, i.e. cultural niche construction.
In this paper, post-harvest methods are used to identify how food processing could feasibly have permitted hominins to modify
their evolutionary selection pressures. Food processing is shown to facilitate access to increasing amounts of digestible
nutrients and energy (kilocalories/kilojoules) as well as promoting increased dietary breadth and making possible the production
of safer and more stable foods. It is argued that these advancements catalysed related technological and ecological skills
and knowledge, which together with the nutritional benefits, further triggered changes in hominin brain and body and locomotory
adaptations and increased longevity, disease prevention and juvenile survival rates. 相似文献
994.
Popular cultural convention holds that, for those with enough gumption, the American frontier was a land of unparalleled opportunity. However, careful research throws doubt on the universality of this convention. Thus, the authors explore factors that increase or decrease opportunities for upward mobility in frontier towns. The authors' longitudinal study of late nineteenth century silver prospectors in Gothic, Colorado, demonstrates that while enthusiastic prospecting in Gothic did not lead to upward social mobility, it did provide enhanced reproductive opportunities. 相似文献
995.
In 1940, when gender specialization was high, there was a negative relationship between education and marriage for women. College-educated women were least likely to be currently married and most likely to be never married. Declines in specialization were accompanied by a transition in this relationship. By 2000, when gender specialization was low, there was a positive relationship between education and marriage for women. College-educated women were most likely to be currently married, in part because they were more likely to stay married or remarry after divorce or widowhood. This transition occurred earlier and more completely for black women than for white women. These changes suggest that the relationship between education and marriage is shaped in part by the gender-role context. 相似文献
996.
We analyze the Supreme Court nomination process in order to provide a general explanation of presidents' propensity to win confirmation battles even in the face of an ideologically hostile Senate. The analysis serves two purposes. First, we argue that employing the conventional measure of the Senate's power to constrain the president's choice of nominees–the median senator–provides an inaccurate picture of this process. In its stead we argue that the filibuster pivot (or the sixtieth most liberal or conservative senator) more accurately captures the Senate's power over the president (Krehbiel 1998). Second, we argue that even under this more stringent spatial constraint, presidents still have the ability to win most confirmation battles with the Senate. Indeed, our results indicate that presidents often overcome situations where the Senate should reject their nominees, or where it should force them to make a less desirable choice, by invoking political capital. 相似文献
997.
998.
E.M.R. Critchley 《Journal of the history of the neurosciences》2013,22(4):243-267
999.
E. M. Murzayev 《Eurasian Geography and Economics》2013,54(5):296-314
The author, an expert in Central Asian toponymy, culture, and physical geography, examines major trends in research on the Aral region's geography by focusing on major themes of paleogeography, bottom and shoreline morphology, hydroclimatic conditions, migration of salts, and forecasting negative impacts of hydrological engineering projects on the region's environment. In the process he presents much interesting material on the early history of the sea and its hinterland (most notably, the deltas of the Syr Dar'ya and Amu Dar'ya) and about differences in the interpretation of quantitative information about the sea by scholars at different times and using different methodologies. 相似文献
1000.
A constitutive model for predicting the cyclic response of reinforced concrete structures is proposed. The model adopts the concept of a smeared crack approach with orthogonal fixed cracks and assumes a plane stress condition. Predictions of the model are compared firstly with existing experimental data on shear walls which were tested under monotonic and cyclic loading. The same model is then used in the finite element analysis of a complete shear wall structure which was tested under a large number of cyclic load reversals due to earthquake loading at NUPEC's Tadotsu Engineering Laboratory. Two different finite element approaches were used, namely a two-dimensional and a three-dimensional representation of the test specimen. The ability of the concrete model to -reproduce the most important characteristics of the dynamic behaviour of this type of structural element was evaluated by comparison with available experimental data. The numerical results showed good correlation between the predicted and the actual response, global as well as local response being reasonable close to the experimental one. 相似文献