全文获取类型
收费全文 | 15136篇 |
免费 | 1557篇 |
国内免费 | 4篇 |
出版年
2021年 | 278篇 |
2020年 | 175篇 |
2019年 | 194篇 |
2018年 | 215篇 |
2017年 | 202篇 |
2016年 | 378篇 |
2015年 | 650篇 |
2014年 | 715篇 |
2013年 | 842篇 |
2012年 | 1105篇 |
2011年 | 998篇 |
2010年 | 643篇 |
2009年 | 582篇 |
2008年 | 807篇 |
2007年 | 787篇 |
2006年 | 713篇 |
2005年 | 668篇 |
2004年 | 691篇 |
2003年 | 651篇 |
2002年 | 653篇 |
2001年 | 241篇 |
2000年 | 234篇 |
1999年 | 222篇 |
1998年 | 201篇 |
1997年 | 129篇 |
1996年 | 133篇 |
1995年 | 125篇 |
1994年 | 101篇 |
1993年 | 110篇 |
1992年 | 177篇 |
1991年 | 149篇 |
1990年 | 204篇 |
1989年 | 128篇 |
1988年 | 136篇 |
1987年 | 138篇 |
1986年 | 119篇 |
1985年 | 132篇 |
1984年 | 128篇 |
1983年 | 104篇 |
1982年 | 122篇 |
1981年 | 122篇 |
1980年 | 106篇 |
1979年 | 122篇 |
1978年 | 103篇 |
1977年 | 108篇 |
1976年 | 81篇 |
1975年 | 87篇 |
1974年 | 83篇 |
1973年 | 83篇 |
1972年 | 78篇 |
排序方式: 共有10000条查询结果,搜索用时 250 毫秒
1.
Herv Canut Johann Bauer Gerhard Weber 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1999,722(1-2)
The review focuses on the multiple separating regimes that offers the free flow electrophoresis technique: free flow zone electrophoresis, isoelectric focusing, isotachophoresis, free flow step electrophoresis. Also, the feasibility to apply either interval or continuous flow electrophoresis is evaluated. The free flow zone electrophoresis regime is generally selected for the separation of cells, organelles and membranes while the other regimes find their largest fields of applications in the purification of proteins and peptides. The latter regimes present the highest resolution efficiency. Therefore, a large part of this review is devoted to the applicabilities of these different regimes to the purification of organelles and membrane vesicles at the preparative scale. Recent developments, both in instrumentation and procedures, are described. The major achievements in plant membrane fractionation obtained with free flow electrophoresis are outlined. The related procedures are both analytical and preparative: they separate tonoplast and plasma membrane simultaneously from the same homogenate, they discriminate for one type of membrane vesicles of opposite orientation, and process large quantities of membrane material by reason of the continuous flow mode. Recent advances using electromigration techniques that permit confirmation of the dynamic state of membranes, characterisation of complex membrane-dependent functions and discovery of new membrane-localised activities are presented. 相似文献
2.
Judith T. Irvine 《American anthropologist》1998,100(2):580-581
The Oral History and Literature of the Wolof People of Waalo, Northern Senegal. Samba Diop. Lewiston, Canada; Edwin Mellen Press, 1995. 389 pp. 相似文献
3.
4.
Quantitative histology of the hypertrophied human heart 总被引:1,自引:0,他引:1
Myocardial hypertrophy accompanies systemic hypertension and aortic stenosis, i.e., pressure overload. In man cardiac failure only appears after years of pressure overload, during which time cardiac function had been maintained. The structural correlates of cardiac failure have been a subject of much interest for many years. Several hypotheses relating alterations in muscle fiber alignment, capillary density, or collagen content have been offered. The application of morphometric techniques has provided essential quantitative information on the structural components of the normal and diseased heart. These data indicate that muscle fiber alignment remains normal in the pressure overloaded heart despite the presence of hypertrophy or the appearance of clinical failure. On the other hand, capillary density is decreased and collagen content is increased in hypertrophied hearts. Chemical studies on collagen concentration however have yielded inconsistent results. The relative contribution of the microcirculation and collagenous structure of the myocardium on its respective O2 availability, mechanical behavior, and deterioration in pump function will require further investigation. 相似文献
5.
6.
Sophie J. Milward Natalie Sebanz 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2016,371(1686)
This opinion piece offers a commentary on the four papers that address the theme of the development of self and other understanding with a view to highlighting the important contribution of developmental research to understanding of mechanisms of social cognition. We discuss potential mechanisms linking self–other distinction and empathy, implications for grouping motor, affective and cognitive domains under a single mechanism, applications of these accounts for joint action and finally consider self–other distinction in group versus dyadic settings. 相似文献
7.
8.
James L Weber 《Biology direct》2006,1(1):16-10
Applications of Genome Polymorphism Scans range from the relatively simple such as gender determination and confirmation of
biological relationships, to the relatively complex such as determination of autozygosity and propagation of genetic information
throughout pedigrees. Unlike nearly all other clinical DNA tests, the Scan is a universal test – it covers all people and
all genes. In balance, I argue that the Genome Polymorphism Scan is the most powerful, affordable clinical DNA test available
today. 相似文献
9.
10.