全文获取类型
收费全文 | 559116篇 |
免费 | 61444篇 |
国内免费 | 2472篇 |
出版年
2021年 | 5089篇 |
2019年 | 4833篇 |
2018年 | 6585篇 |
2017年 | 6035篇 |
2016年 | 8314篇 |
2015年 | 10659篇 |
2014年 | 12767篇 |
2013年 | 17736篇 |
2012年 | 19641篇 |
2011年 | 19722篇 |
2010年 | 13096篇 |
2009年 | 12037篇 |
2008年 | 16642篇 |
2007年 | 17016篇 |
2006年 | 15731篇 |
2005年 | 14880篇 |
2004年 | 14599篇 |
2003年 | 13932篇 |
2002年 | 13283篇 |
2001年 | 28682篇 |
2000年 | 28506篇 |
1999年 | 22187篇 |
1998年 | 6776篇 |
1997年 | 7347篇 |
1996年 | 6749篇 |
1995年 | 6404篇 |
1994年 | 6187篇 |
1993年 | 6093篇 |
1992年 | 17200篇 |
1991年 | 16437篇 |
1990年 | 15791篇 |
1989年 | 15289篇 |
1988年 | 13988篇 |
1987年 | 12994篇 |
1986年 | 12067篇 |
1985年 | 11848篇 |
1984年 | 9677篇 |
1983年 | 8107篇 |
1982年 | 6006篇 |
1981年 | 5387篇 |
1980年 | 5100篇 |
1979年 | 8942篇 |
1978年 | 6807篇 |
1977年 | 6269篇 |
1976年 | 5643篇 |
1975年 | 6234篇 |
1974年 | 6757篇 |
1973年 | 6534篇 |
1972年 | 5974篇 |
1971年 | 5427篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
D L Williamson M P Godard D A Porter D L Costill S W Trappe 《Journal of applied physiology》2000,88(2):627-633
The purpose of this study was to examine myosin heavy chain (MHC) and myosin light chain (MLC) isoforms following 12 wk of progressive resistance training (PRT). A needle biopsy was taken from the vastus lateralis to determine fiber-type expression [ATPase (pH 4.54) and MHC/MLC] in seven healthy men (age = 74.0 +/- 1.8 yr). Subjects were also tested for 1-repetition maximum (1-RM), pre- and posttraining. The progressive knee extensor protocol consisted of three sets at 80% of 1-RM 3 days/wk for 12 wk. Freeze-dried, single muscle fibers were dissected for MHC and MLC analysis and then subjected to SDS-PAGE and silver staining, pre- and posttraining. MHC expression increased in the I (10.4%; P < 0.05) and decreased in I/IIa (9.0%; P < 0.05), I/IIa/x (0.9%; P < 0.05), and IIa/x (8.9%; P < 0.05) isoforms, with no change in the IIa and IIx isoforms, pre- vs. posttraining (total fibers = 3,059). The MLC(3f)-to-MLC(2) ratio did not change with the PRT in either the MHC I or MHC IIa isoforms (total fibers = 902), pre- to posttraining. ATPase fiber distribution did not significantly differ following training (I: 50. 4 +/- 6.7 vs. 51.9 +/- 7.9, IIa: 36.8 +/- 5.3 vs. 41.1 +/- 7.0, IIb: 12.8 +/- 5.6 vs. 7.0 +/- 4.0%; pre- vs. posttraining, respectively). 1-RM increased (51.9%; P < 0.05) from pre- to posttraining. The PRT provide a stimulus for alterations in MHC isoforms, which demonstrated a decrease in all hybrid isoforms and an increase in MHC I expression (not found in the ATPase results), unlike the MLC ratio (3:2), which was not altered with training. 相似文献
992.
993.
S E Moore 《Trends in cell biology》1999,9(11):441-446
N-glycans play important roles during the folding and secretion of glycoproteins. Surprisingly, during the N-glycosylation of glycoproteins, considerable amounts of unconjugated polymannose-type oligosaccharides ('free OS') are generated. Although free oligosaccharides have no known function in mammalian cells, a sophisticated cellular machinery enables them to be cleared from the endoplasmic reticulum (ER) into the cytosol and then re-enter the endomembrane system at the level of the lysosome. One possible function of this pathway is to stop free OS from interfering with the carbohydrate-dependent aspects of glycoprotein folding and transport along the secretory pathway. 相似文献
994.
995.
996.
997.
998.
999.
1000.