全文获取类型
收费全文 | 604725篇 |
免费 | 64038篇 |
国内免费 | 414篇 |
出版年
2018年 | 5625篇 |
2017年 | 5521篇 |
2016年 | 7461篇 |
2015年 | 9200篇 |
2014年 | 10996篇 |
2013年 | 16192篇 |
2012年 | 17949篇 |
2011年 | 18619篇 |
2010年 | 12556篇 |
2009年 | 11519篇 |
2008年 | 16672篇 |
2007年 | 17013篇 |
2006年 | 16267篇 |
2005年 | 15451篇 |
2004年 | 15220篇 |
2003年 | 14758篇 |
2002年 | 14448篇 |
2001年 | 28166篇 |
2000年 | 28281篇 |
1999年 | 22606篇 |
1998年 | 7529篇 |
1997年 | 7875篇 |
1996年 | 7637篇 |
1995年 | 6949篇 |
1994年 | 7048篇 |
1993年 | 6815篇 |
1992年 | 18612篇 |
1991年 | 17892篇 |
1990年 | 17830篇 |
1989年 | 17674篇 |
1988年 | 16311篇 |
1987年 | 15421篇 |
1986年 | 14129篇 |
1985年 | 14514篇 |
1984年 | 11611篇 |
1983年 | 10118篇 |
1982年 | 7491篇 |
1981年 | 6725篇 |
1980年 | 6426篇 |
1979年 | 11047篇 |
1978年 | 8533篇 |
1977年 | 7740篇 |
1976年 | 7429篇 |
1975年 | 8254篇 |
1974年 | 8744篇 |
1973年 | 8701篇 |
1972年 | 7781篇 |
1971年 | 7020篇 |
1970年 | 6219篇 |
1969年 | 5689篇 |
排序方式: 共有10000条查询结果,搜索用时 281 毫秒
931.
932.
A comparison of the respiratory chain in particles from Paracoccus denitrificans and bovine heart mitochondria by EPR spectroscopy 总被引:6,自引:0,他引:6
S P Albracht H W van Verseveld W R Hagen M L Kalkman 《Biochimica et biophysica acta》1980,593(2):173-186
A study is presented on the EPR characteristics of the paramagnetic groups in the respiratory chain present in membrane particles of Paracoccus denitrificans, the respiratory system of which is very similar to that in submitochondrial particles from beef heart. All paramagnetic prosthetic groups of the mitochondrial system are also found in the bacterial plasma membrane. Their properties suggest that the respiratory groups are embedded in very similar protein environments in the two systems. 相似文献
933.
934.
935.
936.
937.
V Gaponenko E Abusamhadneh M B Abbott N Finley G Gasmi-Seabrook R J Solaro M Rance P R Rosevear 《The Journal of biological chemistry》1999,274(24):16681-16684
Conformational exchange has been demonstrated within the regulatory domain of calcium-saturated cardiac troponin C when bound to the NH2-terminal domain of cardiac troponin I-(1-80), and cardiac troponin I-(1-80)DD, having serine residues 23 and 24 mutated to aspartate to mimic the phosphorylated form of the protein. Binding of cardiac troponin I-(1-80) decreases conformational exchange for residues 29, 32, and 34. Comparison of average transverse cross correlation rates show that both the NH2- and COOH-terminal domains of cardiac troponin C tumble with similar correlation times when bound to cardiac troponin I-(1-80). In contrast, the NH2- and COOH-terminal domains in free cardiac troponin C and cardiac troponin C bound cardiac troponin I-(1-80)DD tumble independently. These results suggest that the nonphosphorylated cardiac specific NH2 terminus of cardiac troponin I interacts with the NH2-terminal domain of cardiac troponin C. 相似文献
938.
In Saccharomyces cerevisiae, the unconventional myosin Myo2p is of fundamental importance in polarized growth. We explore the role of the neck region and its associated light chains in regulating Myo2p function. Surprisingly, we find that precise deletion of the six IQ sites in the neck region results in a myosin, Myo2-Δ6IQp, that can support the growth of a yeast strain at 90% the rate of a wild-type isogenic strain. We exploit this mutant in a characterization of the light chains of Myo2p. First, we demonstrate that the localization of calmodulin to sites of polarized growth largely depends on the IQ sites in the neck of Myo2p. Second, we demonstrate that a previously uncharacterized protein, Mlc1p, is a myosin light chain of Myo2p. MLC1 (YGL106w) is an essential gene that exhibits haploinsufficiency. Reduced levels of MYO2 overcome the haploinsufficiency of MLC1. The mutant MYO2-Δ6IQ is able to suppress haploinsufficiency but not deletion of MLC1. We used a modified gel overlay assay to demonstrate a direct interaction between Mlc1p and the neck of Myo2p. Overexpression of MYO2 is toxic, causing a severe decrease in growth rate. When MYO2 is overexpressed, Myo2p is fourfold less stable than in a wild-type strain. High copies of MLC1 completely overcome the growth defects and increase the stability of Myo2p. Our results suggest that Mlc1p is responsible for stabilizing this myosin by binding to the neck region. 相似文献
939.
940.