全文获取类型
收费全文 | 29673篇 |
免费 | 15854篇 |
国内免费 | 2篇 |
出版年
2023年 | 33篇 |
2022年 | 128篇 |
2021年 | 519篇 |
2020年 | 2221篇 |
2019年 | 3774篇 |
2018年 | 3894篇 |
2017年 | 4159篇 |
2016年 | 4196篇 |
2015年 | 4179篇 |
2014年 | 3826篇 |
2013年 | 4279篇 |
2012年 | 2039篇 |
2011年 | 1707篇 |
2010年 | 3180篇 |
2009年 | 1900篇 |
2008年 | 865篇 |
2007年 | 452篇 |
2006年 | 420篇 |
2005年 | 441篇 |
2004年 | 420篇 |
2003年 | 408篇 |
2002年 | 343篇 |
2001年 | 379篇 |
2000年 | 297篇 |
1999年 | 212篇 |
1998年 | 59篇 |
1997年 | 49篇 |
1996年 | 52篇 |
1995年 | 54篇 |
1994年 | 55篇 |
1993年 | 47篇 |
1992年 | 79篇 |
1991年 | 67篇 |
1990年 | 86篇 |
1989年 | 72篇 |
1988年 | 77篇 |
1987年 | 65篇 |
1986年 | 69篇 |
1985年 | 55篇 |
1984年 | 36篇 |
1983年 | 37篇 |
1982年 | 27篇 |
1981年 | 21篇 |
1980年 | 22篇 |
1979年 | 23篇 |
1978年 | 21篇 |
1977年 | 22篇 |
1976年 | 21篇 |
1974年 | 19篇 |
1973年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
971.
Tracie Pennimpede Stefanie Wolter Lars Wittler Anne‐Karoline Ebert Wolfgang Rösch Raimund Stein Enrika Bartels Dominik Schmidt Thomas M. Boemers Eberhard Schmiedeke Per Hoffmann Susanne Moebus Bernhard G. Herrmann Markus M. Nöthen Heiko Reutter Michael Ludwig 《Birth defects research. Part A, Clinical and molecular teratology》2013,97(3):133-139
972.
973.
974.
975.
976.
977.
Jean-Luc Montillet Nathalie Leonhardt Samuel Mondy Sylvain Tranchimand Dominique Rumeau Marie Boudsocq Ana Victoria Garcia Thierry Douki Jean Bigeard Christiane Laurière Anne Chevalier Carmen Castresana Heribert Hirt 《PLoS biology》2013,11(3)
Plant stomata function in innate immunity against bacterial invasion and abscisic acid (ABA) has been suggested to regulate this process. Using genetic, biochemical, and pharmacological approaches, we demonstrate that (i) the Arabidopsis thaliana nine-specific-lipoxygenase encoding gene, LOX1, which is expressed in guard cells, is required to trigger stomatal closure in response to both bacteria and the pathogen-associated molecular pattern flagellin peptide flg22; (ii) LOX1 participates in stomatal defense; (iii) polyunsaturated fatty acids, the LOX substrates, trigger stomatal closure; (iv) the LOX products, fatty acid hydroperoxides, or reactive electrophile oxylipins induce stomatal closure; and (v) the flg22-mediated stomatal closure is conveyed by both LOX1 and the mitogen-activated protein kinases MPK3 and MPK6 and involves salicylic acid whereas the ABA-induced process depends on the protein kinases OST1, MPK9, or MPK12. Finally, we show that the oxylipin and the ABA pathways converge at the level of the anion channel SLAC1 to regulate stomatal closure. Collectively, our results demonstrate that early biotic signaling in guard cells is an ABA-independent process revealing a novel function of LOX1-dependent stomatal pathway in plant immunity. 相似文献
978.
Danilo Garcia Sebastian Lundstr?m Sven Br?ndstr?m Maria R?stam C. Robert Cloninger Nóra Kerekes Thomas Nilsson Henrik Anckars?ter 《PloS one》2013,8(8)
Background
The Child and Adolescent Twin Study in Sweden (CATSS) is an on-going, large population-based longitudinal twin study. We aimed (1) to investigate the reliability of two different versions (125-items and 238-items) of Cloninger''s Temperament and Character Inventory (TCI) used in the CATSS and the validity of extracting the short version from the long version, (2) to compare these personality dimensions between twins and adolescents from the general population, and (3) to investigate the genetic structure of Cloninger''s model.Method
Reliability and correlation analyses were conducted for both TCI versions, 2,714 CATSS-twins were compared to 631 adolescents from the general population, and the genetic structure was investigated through univariate genetic analyses, using a model-fitting approach with structural equation-modeling techniques based on same-sex twin pairs from the CATSS (423 monozygotic and 408 dizygotic pairs).Results
The TCI scores from the short and long versions showed comparable reliability coefficients and were strongly correlated. Twins scored about half a standard deviation higher in the character scales. Three of the four temperament dimensions (Novelty Seeking, Harm Avoidance, and Persistence) had strong genetic and non-shared environmental effects, while Reward Dependence and the three character dimensions had moderate genetic effects, and both shared and non-shared environmental effects.Conclusions
Twins showed higher scores in character dimensions compared to adolescents from the general population. At least among adolescents there is a shared environmental influence for all of the character dimensions, but only for one of the temperament dimensions (i.e., Reward Dependence). This specific finding regarding the existence of shared environmental factors behind the character dimensions in adolescence, together with earlier findings showing a small shared environmental effects on character among young adults and no shared environmental effects on character among adults, suggest that there is a shift in type of environmental influence from adolescence to adulthood regarding character. 相似文献979.
980.
Androgens are thought to mediate sexual differentiation of spinal nucleus of the bulbocavernosus (SNB) motoneurons via actions on androgen receptors (ARs) within their target muscles bulbocavernosus and levator ani (LA). However, the cells within these muscles which mediate masculinization of the SNB remain undefined. Until recently, myocytes were thought to be the most likely candidate cell type. However, genetic tests of AR function in myocytes have failed to support a sufficient role for these cells in producing masculine SNB morphology, suggesting the involvement of other cell types. To identify other candidate cell types in the LA, we evaluated whether satellite cells or fibroblasts express AR. Fluorescent immunohistochemistry and confocal microscopy were used to evaluate whether satellite cells and fibroblasts express AR in neonatal male and female rats in the LA and an adjacent sexually monomorphic control muscle (CM). We found that a small proportion of satellite cells in the LA express AR and that this proportion is significantly greater in the LA compared to the CM. No sex differences were found between the proportions of satellite cells expressing AR in either muscle. Less colocalization of satellite cells and AR was seen in postnatal day 3 muscle than in postnatal day 1 muscle. In contrast, only negligible amounts of fibroblasts labeled with S100A4 express AR in either the LA or the CM. Together, findings support satellite cells, but not fibroblasts, as a candidate cell type involved in the sexual differentiation of the SNB neuromuscular system. © 2012 Wiley Periodicals, Inc. Develop Neurobiol 73: 448–454, 2013. 相似文献