全文获取类型
收费全文 | 86941篇 |
免费 | 7681篇 |
国内免费 | 42篇 |
专业分类
94664篇 |
出版年
2023年 | 282篇 |
2022年 | 707篇 |
2021年 | 1553篇 |
2020年 | 883篇 |
2019年 | 1118篇 |
2018年 | 1444篇 |
2017年 | 1252篇 |
2016年 | 2148篇 |
2015年 | 3651篇 |
2014年 | 4073篇 |
2013年 | 4855篇 |
2012年 | 6574篇 |
2011年 | 6521篇 |
2010年 | 4200篇 |
2009年 | 3826篇 |
2008年 | 5469篇 |
2007年 | 5471篇 |
2006年 | 5264篇 |
2005年 | 5075篇 |
2004年 | 4932篇 |
2003年 | 4695篇 |
2002年 | 4439篇 |
2001年 | 895篇 |
2000年 | 653篇 |
1999年 | 992篇 |
1998年 | 1240篇 |
1997年 | 830篇 |
1996年 | 755篇 |
1995年 | 665篇 |
1994年 | 621篇 |
1993年 | 677篇 |
1992年 | 578篇 |
1991年 | 548篇 |
1990年 | 482篇 |
1989年 | 414篇 |
1988年 | 437篇 |
1987年 | 364篇 |
1986年 | 334篇 |
1985年 | 415篇 |
1984年 | 532篇 |
1983年 | 423篇 |
1982年 | 520篇 |
1981年 | 501篇 |
1980年 | 426篇 |
1979年 | 316篇 |
1978年 | 335篇 |
1977年 | 296篇 |
1976年 | 278篇 |
1975年 | 224篇 |
1974年 | 259篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
62.
63.
Michael S. Lipkowitz Edgar Leal-Pinto B. Eleazar Cohen Ruth G. Abramson 《Glycoconjugate journal》2002,19(7-9):491-498
UAT, also designated galectin 9, is a multifunctional protein that can function as a urate channel/transporter, a regulator of thymocyte-epithelial cell interactions, a tumor antigen, an eosinophil chemotactic factor, and a mediator of apoptosis. We review the evidence that UAT is a transmembrane protein that transports urate, describe our molecular model for this protein, and discuss the evidence from epitope tag and lipid bilayer studies that support this model of the transporter. The properties of recombinant UAT are compared with those of urate transport into membrane vesicles derived from proximal tubule cells in rat kidney cortex. In addition, we review channel functions predicted by our molecular model that resulted in the novel finding that the urate channel activity is regulated by sugars and adenosine. Finally, the presence and possible functions of at least 4 isoforms of UAT and a closely related gene hUAT2 are discussed. Published in 2004. 相似文献
64.
65.
66.
Krajana Tainchum Wanapa Ritthison Thipwara Chuaycharoensuk Michael J. Bangs Sylvie Manguin Theeraphap Chareonviriyaphap 《Journal of vector ecology》2014,39(2):424-436
We determined the species diversity, blood‐feeding behavior, and host preference of Anopheles mosquitoes in two malaria endemic areas of Tak (Mae Sot District) and Mae Hong Son (Sop Moei District) Provinces, located along the Thai border with Myanmar, during a consecutive two‐year period. Anopheline mosquitoes were collected using indoor and outdoor human‐landing captures and outdoor cow‐baited collections. Mosquitoes were initially identified using morphological characters, followed by the appropriate multiplex AS‐PCR assay for the identification of sibling species within Anopheles (Cellia) complexes and groups present. Real‐time PCR was performed for parasite‐specific detection in mosquitoes (Plasmodium spp. and Wuchereria bancrofti). A total of 7,129 Anopheles females were captured, 3,939 from Mae Sot and 3,190 from Sop Moei, with 58.6% and 37% of all anophelines identified as An. minimus, respectively. All three malaria vector complexes were detected in both areas. One species within the Minimus Complex (An. minimus) was present along with two related species in the Funestus Group, (An. aconitus, An. varuna), two species within the Dirus Complex (An. dirus, An. baimaii), and four species within the Maculatus Group (An. maculatus, An. sawadwongporni, An. pseudowillmori, and An. dravidicus). The trophic behavior of An. minimus, An. dirus, An. baimaii, An. maculatus, and An. sawadwongporni are described herein. The highest An. minimus densities were detected from February through April of both years. One specimen of An. minimus from Mae Sot was found positive for Plasmodium vivax. 相似文献
67.
Amy Chapman Gonzalo Gonzales Wayne R. Burrowes Paul Assanah Bernadette Iannone Michael K. Leung George B. Stefano 《Cellular and molecular neurobiology》1984,4(2):143-155
In Mytilus and Leucophaea the high-affinity binding site density is significantly lower in old animals than in young animals, whereas the low-affinity site density remains unchanged. In Mytilus the estimated met-enkephalin and met-enkephalin-Arg6-Phe7 levels are significantly higher in old than in young animals. In Leucophaea only the met-enkephalin level can be determined, and it is also higher in old animals. The decrease in the high-affinity binding site density and the corresponding increase in endogenous enkephalin levels suggest the existence of an opioid compensatory mechanism associated with the aging process. In Mytilus there is a demonstrated decrease with age in intraganglionic dopamine levels in response to applied opiates. In addition, the inhibition of dopamine-stimulated adenylate cyclase activity by opiates also decreases in older animals. In Leucophaea the sex difference in opioid binding densities diminishes with age. 相似文献
68.
Plasma choline concentrations were measured in humans, rats, and rabbits within the first few hours of life, before any food was ingested. Neonatal animals and humans had markedly elevated plasma choline levels compared to adult animals or humans. Possible mechanisms responsible for this elevation are discussed and possible consequences for brain function, lung function, and growth are presented. 相似文献
69.
70.