全文获取类型
收费全文 | 538篇 |
免费 | 3篇 |
国内免费 | 5篇 |
专业分类
系统科学 | 15篇 |
教育与普及 | 1篇 |
理论与方法论 | 9篇 |
现状及发展 | 208篇 |
研究方法 | 104篇 |
综合类 | 198篇 |
自然研究 | 11篇 |
出版年
2020年 | 3篇 |
2018年 | 16篇 |
2017年 | 10篇 |
2016年 | 21篇 |
2015年 | 14篇 |
2014年 | 10篇 |
2013年 | 14篇 |
2012年 | 47篇 |
2011年 | 64篇 |
2010年 | 24篇 |
2009年 | 11篇 |
2008年 | 35篇 |
2007年 | 27篇 |
2006年 | 38篇 |
2005年 | 27篇 |
2004年 | 34篇 |
2003年 | 22篇 |
2002年 | 25篇 |
1999年 | 3篇 |
1997年 | 2篇 |
1995年 | 2篇 |
1991年 | 1篇 |
1987年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 8篇 |
1976年 | 5篇 |
1975年 | 5篇 |
1974年 | 3篇 |
1973年 | 8篇 |
1972年 | 6篇 |
1971年 | 7篇 |
1970年 | 4篇 |
1969年 | 2篇 |
1968年 | 2篇 |
1966年 | 3篇 |
1965年 | 2篇 |
1964年 | 3篇 |
1962年 | 1篇 |
1960年 | 1篇 |
1959年 | 1篇 |
1957年 | 1篇 |
1956年 | 1篇 |
1955年 | 5篇 |
1954年 | 1篇 |
1947年 | 1篇 |
排序方式: 共有546条查询结果,搜索用时 109 毫秒
221.
222.
223.
224.
225.
226.
A. Giacomello C. Salerno Maria Concetta Gigante 《Cellular and molecular life sciences : CMLS》1981,37(10):1070-1071
Summary The affinity between purified rheumatoid factors (RF) and native or heat aggregated human IgG has been studied in vitro by polarization florescence in the presence and in the absence of D-penicillamine. The value of the dissociation constant was the same using native and heat aggregated IgG suggesting that binding to the aggregated protein is not dependent on the exposure of a new determinant lacking in the native molecule. The results obtained in the presence of D-penicillamine suggest that the concentration of the drug necessary to get a pronounced effect on the apparent dissociation constant of the immunocomplex between IgG and RF is not reached in vivo, in clinical situations. 相似文献
227.
The concentration of high molecular weight kininogen antigen in homogenates of various human tissues
J. Kleniewski Maria Bogumił-Oczkowska 《Cellular and molecular life sciences : CMLS》1980,36(3):354-356
Summary The concentration of high molecular weight kininogen, measured in human tissue homogenates, was 2–3 times higher in kidneys, adrenals and thyroid than in homogenates of lung, heart, liver and spleen. No measurable quantities of this protein were found in homogenates of brain and skeletal muscles.This work was supported by a grant from the Department of Medical Sciences of Polish Academy of Sciences. 相似文献
228.
A. A. Marino Maria Reichmanis R. O. Becker Betsy Ullrich J. M. Cullen 《Cellular and molecular life sciences : CMLS》1980,36(3):309-311
Summary Electromagnetic fields arising from the electrical power system are pervasively present in the environment. To help evaluate their public-health risk we raised 3 successive generations of mice in a low-strength, 60-Hz electric field. We found that the field caused an increased mortality in each generation, and, altered body weights in the 3rd generation.This work was supported by the National Institute of Environmental Health Sciences, Department of Health, Education and Welfare, the Environmental Protection Agency, and the Veterans Administration. 相似文献
229.
U. Lerner Maria Ransjö G. T. Gustafson 《Cellular and molecular life sciences : CMLS》1981,37(7):761-762
Summary Spontaneous bone resorption is reduced in cultured calvarial bones from mice with the Chediak-Higashi syndrome, as indicated by decreased mobilization of calcium from the bones to the medium. Although bone resorption in calvaria from mice with this disease can be stimulated by PGE2 and 1 (OH)D3, the amounts of mineral released after stimulation is also decreased.This investigation was supported by grants from the Swedish Association against Rheumatic Diseases, from the Royal 80 Year Fund of King Gustav V, and from the Swedish Medical Research Council (project No 14X-05426). 相似文献
230.
Linking climate change to lemming cycles 总被引:2,自引:0,他引:2
Kausrud KL Mysterud A Steen H Vik JO Østbye E Cazelles B Framstad E Eikeset AM Mysterud I Solhøy T Stenseth NC 《Nature》2008,456(7218):93-97
The population cycles of rodents at northern latitudes have puzzled people for centuries, and their impact is manifest throughout the alpine ecosystem. Climate change is known to be able to drive animal population dynamics between stable and cyclic phases, and has been suggested to cause the recent changes in cyclic dynamics of rodents and their predators. But although predator-rodent interactions are commonly argued to be the cause of the Fennoscandian rodent cycles, the role of the environment in the modulation of such dynamics is often poorly understood in natural systems. Hence, quantitative links between climate-driven processes and rodent dynamics have so far been lacking. Here we show that winter weather and snow conditions, together with density dependence in the net population growth rate, account for the observed population dynamics of the rodent community dominated by lemmings (Lemmus lemmus) in an alpine Norwegian core habitat between 1970 and 1997, and predict the observed absence of rodent peak years after 1994. These local rodent dynamics are coherent with alpine bird dynamics both locally and over all of southern Norway, consistent with the influence of large-scale fluctuations in winter conditions. The relationship between commonly available meteorological data and snow conditions indicates that changes in temperature and humidity, and thus conditions in the subnivean space, seem to markedly affect the dynamics of alpine rodents and their linked groups. The pattern of less regular rodent peaks, and corresponding changes in the overall dynamics of the alpine ecosystem, thus seems likely to prevail over a growing area under projected climate change. 相似文献