全文获取类型
收费全文 | 8441篇 |
免费 | 830篇 |
国内免费 | 6篇 |
出版年
2021年 | 74篇 |
2020年 | 61篇 |
2019年 | 83篇 |
2018年 | 100篇 |
2017年 | 101篇 |
2016年 | 164篇 |
2015年 | 295篇 |
2014年 | 303篇 |
2013年 | 419篇 |
2012年 | 567篇 |
2011年 | 541篇 |
2010年 | 351篇 |
2009年 | 333篇 |
2008年 | 526篇 |
2007年 | 539篇 |
2006年 | 488篇 |
2005年 | 501篇 |
2004年 | 476篇 |
2003年 | 451篇 |
2002年 | 370篇 |
2001年 | 98篇 |
2000年 | 94篇 |
1999年 | 99篇 |
1998年 | 107篇 |
1997年 | 81篇 |
1996年 | 75篇 |
1995年 | 81篇 |
1994年 | 60篇 |
1993年 | 78篇 |
1992年 | 89篇 |
1991年 | 73篇 |
1990年 | 69篇 |
1989年 | 72篇 |
1988年 | 73篇 |
1987年 | 70篇 |
1986年 | 58篇 |
1985年 | 64篇 |
1984年 | 70篇 |
1983年 | 68篇 |
1982年 | 71篇 |
1981年 | 63篇 |
1980年 | 68篇 |
1979年 | 61篇 |
1978年 | 55篇 |
1977年 | 52篇 |
1976年 | 41篇 |
1975年 | 45篇 |
1974年 | 65篇 |
1973年 | 55篇 |
1972年 | 43篇 |
排序方式: 共有9277条查询结果,搜索用时 15 毫秒
1.
Keith M. Harris Jia-Jia Syu Owen D. Lello Y. L. Eileen Chew Christopher H. Willcox Roger H. M. Ho 《PloS one》2015,10(6)
There is considerable need for accurate suicide risk assessment for clinical, screening, and research purposes. This study applied the tripartite affect-behavior-cognition theory, the suicidal barometer model, classical test theory, and item response theory (IRT), to develop a brief self-report measure of suicide risk that is theoretically-grounded, reliable and valid. An initial survey (n = 359) employed an iterative process to an item pool, resulting in the six-item Suicidal Affect-Behavior-Cognition Scale (SABCS). Three additional studies tested the SABCS and a highly endorsed comparison measure. Studies included two online surveys (Ns = 1007, and 713), and one prospective clinical survey (n = 72; Time 2, n = 54). Factor analyses demonstrated SABCS construct validity through unidimensionality. Internal reliability was high (α = .86-.93, split-half = .90-.94)). The scale was predictive of future suicidal behaviors and suicidality (r = .68, .73, respectively), showed convergent validity, and the SABCS-4 demonstrated clinically relevant sensitivity to change. IRT analyses revealed the SABCS captured more information than the comparison measure, and better defined participants at low, moderate, and high risk. The SABCS is the first suicide risk measure to demonstrate no differential item functioning by sex, age, or ethnicity. In all comparisons, the SABCS showed incremental improvements over a highly endorsed scale through stronger predictive ability, reliability, and other properties. The SABCS is in the public domain, with this publication, and is suitable for clinical evaluations, public screening, and research. 相似文献
2.
3.
4.
Ghotas Evindar Sylvie G. Bernier Malcolm J. Kavarana Elisabeth Doyle Jeanine Lorusso Michael S. Kelley Keith Halley Amy Hutchings Albion D. Wright Ashis K. Saha Gerhard Hannig Barry A. Morgan William F. Westlin 《Bioorganic & medicinal chemistry letters》2009,19(2):369-372
In the design of potent and selective sphingosine-1-phosphate receptor agonists, we were able to identify two series of molecules based on phenylamide and phenylimidazole analogs of FTY-720. Several designed molecules in these scaffolds have demonstrated selectivity for S1P receptor subtype 1 versus 3 and excellent in vivo activity in mouse. Two molecules PPI-4621 (4b) and PPI-4691 (10a), demonstrated dose responsive lymphopenia, when administered orally. 相似文献
5.
Ruofan Wang Camille R. Simoneau Jessie Kulsuptrakul Mehdi Bouhaddou Katherine A. Travisano Jennifer M. Hayashi Jared Carlson-Stevermer James R. Zengel Christopher M. Richards Parinaz Fozouni Jennifer Oki Lauren Rodriguez Bastian Joehnk Keith Walcott Kevin Holden Anita Sil Jan E. Carette Nevan J. Krogan Andreas S. Puschnik 《Cell》2021,184(1):106-119.e14
6.
Elizabeth Storer Scholl Antonella Pirone Daniel H Cox R Keith Duncan Michele H Jacob 《Channels (Austin, Tex.)》2014,8(1):62-75
Small conductance Ca2+-sensitive potassium (SK2) channels are voltage-independent, Ca2+-activated ion channels that conduct potassium cations and thereby modulate the intrinsic excitability and synaptic transmission of neurons and sensory hair cells. In the cochlea, SK2 channels are functionally coupled to the highly Ca2+ permeant α9/10-nicotinic acetylcholine receptors (nAChRs) at olivocochlear postsynaptic sites. SK2 activation leads to outer hair cell hyperpolarization and frequency-selective suppression of afferent sound transmission. These inhibitory responses are essential for normal regulation of sound sensitivity, frequency selectivity, and suppression of background noise. However, little is known about the molecular interactions of these key functional channels. Here we show that SK2 channels co-precipitate with α9/10-nAChRs and with the actin-binding protein α-actinin-1. SK2 alternative splicing, resulting in a 3 amino acid insertion in the intracellular 3′ terminus, modulates these interactions. Further, relative abundance of the SK2 splice variants changes during developmental stages of synapse maturation in both the avian cochlea and the mammalian forebrain. Using heterologous cell expression to separately study the 2 distinct isoforms, we show that the variants differ in protein interactions and surface expression levels, and that Ca2+ and Ca2+-bound calmodulin differentially regulate their protein interactions. Our findings suggest that the SK2 isoforms may be distinctly modulated by activity-induced Ca2+ influx. Alternative splicing of SK2 may serve as a novel mechanism to differentially regulate the maturation and function of olivocochlear and neuronal synapses. 相似文献
7.
8.
9.
10.