全文获取类型
收费全文 | 2875篇 |
免费 | 275篇 |
出版年
2021年 | 47篇 |
2020年 | 23篇 |
2019年 | 40篇 |
2018年 | 49篇 |
2017年 | 33篇 |
2016年 | 69篇 |
2015年 | 122篇 |
2014年 | 131篇 |
2013年 | 175篇 |
2012年 | 176篇 |
2011年 | 209篇 |
2010年 | 130篇 |
2009年 | 109篇 |
2008年 | 149篇 |
2007年 | 210篇 |
2006年 | 181篇 |
2005年 | 168篇 |
2004年 | 134篇 |
2003年 | 144篇 |
2002年 | 163篇 |
2001年 | 34篇 |
2000年 | 24篇 |
1999年 | 35篇 |
1998年 | 34篇 |
1997年 | 28篇 |
1996年 | 24篇 |
1995年 | 28篇 |
1994年 | 21篇 |
1993年 | 32篇 |
1992年 | 22篇 |
1991年 | 23篇 |
1990年 | 21篇 |
1989年 | 23篇 |
1988年 | 27篇 |
1987年 | 26篇 |
1986年 | 28篇 |
1985年 | 24篇 |
1984年 | 18篇 |
1983年 | 8篇 |
1982年 | 13篇 |
1981年 | 17篇 |
1980年 | 23篇 |
1979年 | 15篇 |
1978年 | 15篇 |
1977年 | 10篇 |
1975年 | 14篇 |
1973年 | 13篇 |
1972年 | 10篇 |
1971年 | 12篇 |
1969年 | 8篇 |
排序方式: 共有3150条查询结果,搜索用时 46 毫秒
1.
2.
Carolyn Beebe Smith 《Neurochemical research》1991,16(9):1037-1046
Special issue dedicated to Dr. Louis Sokoloff. 相似文献
3.
Carolyn Jean Babula 《American anthropologist》1998,100(2):549-550
Clothing and Difference: Embodied Identities in Colonial and Post-Colonial Africa. Hildi Hendrickson. ed. Durham, NC: Duke University Press, 1996. 268 pp. 相似文献
4.
Studies on the ecology of microbial parasites and their hosts are predicated on understanding the assemblage of and relationship among the species present. Changes in organismal morphology and physiology can have profound effects on host–parasite interactions and associated microbial community structure. The marine rickettsial organism, “Candidatus Xenohaliotis californiensis” (WS-RLO), that causes withering syndrome of abalones has had a consistent morphology based on light and electron microscopy. However, a morphological variant of the WS-RLO has recently been observed infecting red abalone from California. We used light and electron microscopy, in situ hybridization and16S rDNA sequence analysis to compare the WS-RLO and the morphologically distinct RLO variant (RLOv). The WS-RLO forms oblong inclusions within the abalone posterior esophagus (PE) and digestive gland (DG) tissues that contain small rod-shaped bacteria; individual bacteria within the light purple inclusions upon hematoxylin and eosin staining cannot be discerned by light microscopy. Like the WS-RLO, the RLOv forms oblong inclusions in the PE and DG but contain large, pleomorphic bacteria that stain dark navy blue with hematoxylin and eosin. Transmission electron microscopy (TEM) examination revealed that the large pleomorphic bacteria within RLOv inclusions were infected with a spherical to icosahedral-shaped putative phage hyperparasite. TEM also revealed the presence of rod-shaped bacteria along the periphery of the RLOv inclusions that were morphologically indistinguishable from the WS-RLO. Binding of the WS-RLO-specific in situ hybridization probe to the RLOv inclusions demonstrated sequence similarity between these RLOs. In addition, sequence analysis revealed 98.9–99.4 % similarity between 16S rDNA sequences of the WS-RLO and RLOv. Collectively, these data suggest that both of these RLOs infecting California abalone are “Candidatus Xenohaliotis californiensis,” and that the novel variant is infected by a putative phage hyperparasite that induced morphological variation of its RLO host. 相似文献
5.
The preferred mechanisms of racemization for three tris chelate complexes, Co(acac)3, Fe(phen)3 3+ and Fe[S2CN(CH2)4]3, were investigated by molecular modeling. The transition states for both a Bailar twist and a Rây-Dutt twist were considered; semi-empirical calculations (PM3) yielded activation energies. The preferred mechanism was the Bailar twist for Co(acac)3 and Fe[S2CN(CH2)4]3 with activation energies of 83.2 and 7.3 kcal mol−1, respectively, and the Rây-Dutt twist for Fe(phen)3 3+ with an activation energy of 114.4 kcal mol−1. These results are compared with those of geometrical models. 相似文献
6.
7.
8.
9.
10.
Carolyn B. Yucha 《Applied psychophysiology and biofeedback》2002,27(1):113-114
The author replies to the comments of Drs Blanchard and McGrady, urging that researchers reinvigorate their research efforts in complementary and alternative treatments for hypertension. In subsequent research there is a need to assess treatment adherence, to use more rigorous outcome measures, and to develop new outcome measures that assess impact and improvement in quality of life. 相似文献