全文获取类型
收费全文 | 80428篇 |
免费 | 6658篇 |
国内免费 | 32篇 |
专业分类
87118篇 |
出版年
2022年 | 465篇 |
2021年 | 1012篇 |
2020年 | 653篇 |
2019年 | 768篇 |
2018年 | 1205篇 |
2017年 | 1163篇 |
2016年 | 1781篇 |
2015年 | 2787篇 |
2014年 | 3013篇 |
2013年 | 4104篇 |
2012年 | 5605篇 |
2011年 | 5699篇 |
2010年 | 3512篇 |
2009年 | 2946篇 |
2008年 | 4769篇 |
2007年 | 4812篇 |
2006年 | 4562篇 |
2005年 | 4449篇 |
2004年 | 4347篇 |
2003年 | 4105篇 |
2002年 | 4022篇 |
2001年 | 1550篇 |
2000年 | 1475篇 |
1999年 | 1177篇 |
1998年 | 1062篇 |
1997年 | 741篇 |
1996年 | 792篇 |
1995年 | 755篇 |
1994年 | 713篇 |
1993年 | 739篇 |
1992年 | 703篇 |
1991年 | 636篇 |
1990年 | 544篇 |
1989年 | 545篇 |
1988年 | 545篇 |
1987年 | 476篇 |
1986年 | 485篇 |
1985年 | 555篇 |
1984年 | 607篇 |
1983年 | 506篇 |
1982年 | 622篇 |
1981年 | 568篇 |
1980年 | 473篇 |
1979年 | 382篇 |
1978年 | 396篇 |
1977年 | 389篇 |
1976年 | 322篇 |
1975年 | 319篇 |
1974年 | 330篇 |
1973年 | 311篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
Sixin Jiang Brigitte Heller Vincent S. Tagliabracci Lanmin Zhai Jose M. Irimia Anna A. DePaoli-Roach Clark D. Wells Alexander V. Skurat Peter J. Roach 《The Journal of biological chemistry》2010,285(45):34960-34971
Stbd1 is a protein of previously unknown function that is most prevalent in liver and muscle, the major sites for storage of the energy reserve glycogen. The protein is predicted to contain a hydrophobic N terminus and a C-terminal CBM20 glycan binding domain. Here, we show that Stbd1 binds to glycogen in vitro and that endogenous Stbd1 locates to perinuclear compartments in cultured mouse FL83B or Rat1 cells. When overexpressed in COSM9 cells, Stbd1 concentrated at enlarged perinuclear structures, co-localized with glycogen, the late endosomal/lysosomal marker LAMP1 and the autophagy protein GABARAPL1. Mutant Stbd1 lacking the N-terminal hydrophobic segment had a diffuse distribution throughout the cell. Point mutations in the CBM20 domain did not change the perinuclear localization of Stbd1, but glycogen was no longer concentrated in this compartment. Stable overexpression of glycogen synthase in Rat1WT4 cells resulted in accumulation of glycogen as massive perinuclear deposits, where a large fraction of the detectable Stbd1 co-localized. Starvation of Rat1WT4 cells for glucose resulted in dissipation of the massive glycogen stores into numerous and much smaller glycogen deposits that retained Stbd1. In vitro, in cells, and in animal models, Stbd1 consistently tracked with glycogen. We conclude that Stbd1 is involved in glycogen metabolism by binding to glycogen and anchoring it to membranes, thereby affecting its cellular localization and its intracellular trafficking to lysosomes. 相似文献
82.
83.
H Härtel S Nikunen E Neuvonen R Tanskanen S-L Kivelä P Aho T Soveri H Saloniemi 《Acta veterinaria Scandinavica》2004,45(4):193-200
Pathogens causing bovine respiratory tract disease in Finland were investigated. Eighteen cattle herds with bovine respiratory
disease were included. Five diseased calves from each farm were chosen for closer examination and tracheobronchial lavage.
Blood samples were taken from the calves at the time of the investigation and from 86 calves 3–4 weeks later. In addition,
6–10 blood samples from animals of different ages were collected from each herd, resulting in 169 samples. Serum samples were
tested for antibodies to bovine parainfluenza virus-3 (PIV-3), bovine respiratory syncytial virus (BRSV), bovine coronavirus
(BCV), bovine adenovirus-3 (BAV-3) and bovine adenovirus-7 (BAV-7). About one third of the samples were also tested for antibodies
to bovine virus diarrhoea virus (BVDV) with negative results. Bacteria were cultured from lavage fluid and in vitro susceptibility
to selected antimicrobials was tested. According to serological findings, PIV-3, BAV-7, BAV-3, BCV and BRSV are common pathogens
in Finnish cattle with respiratory problems. A titre rise especially for BAV-7 and BAV-3, the dual growth of Mycoplasma dispar and Pasteurella multocida, were typical findings in diseased calves. Pasteurella sp. strains showed no resistance to tested antimicrobials. Mycoplasma bovis and Mannheimia haemolytica were not found. 相似文献
84.
85.
Peter J. Meloncelli 《Carbohydrate research》2010,345(16):2305-2322
The ABO histo-blood group system is one of the most clinically important antigen families. As part of our overall goal to prepare the entire set of the A, B and H type I-VI antigens for a range of biochemical investigations, we report herein the synthesis of the type I and II antigens with a 7-octen-1-yl aglycone. This linker was chosen to facilitate not only the future conjugation of the antigens to a protein or solid support but also the synthesis of the H type I and II octyl glycosides for enzyme kinetic studies. 相似文献
86.
87.
88.
Human migration is nonrandom. In small scale societies of the past, and in the modern world, people tend to move to wealthier, safer, and more just societies from poorer, more violent, less just societies. If immigrants are assimilated, such nonrandom migration can increase the occurrence of culturally transmitted beliefs, values, and institutions that cause societies to be attractive to immigrants. Here we describe and analyze a simple model of this process. This model suggests that long run outcomes depend on the relative strength of migration and local adaptation. When local adaption is strong enough to preserve cultural variation among groups, cultural variants that make societies attractive always predominate, but never drive alternative variants to extinction. When migration predominates, outcomes depend both on the relative attractiveness of alternative variants and on the initial sizes of societies that provide and receive immigrants. 相似文献
89.