全文获取类型
收费全文 | 534337篇 |
免费 | 54043篇 |
国内免费 | 1081篇 |
专业分类
589461篇 |
出版年
2018年 | 16882篇 |
2017年 | 15862篇 |
2016年 | 13134篇 |
2015年 | 7523篇 |
2014年 | 8223篇 |
2013年 | 11693篇 |
2012年 | 17681篇 |
2011年 | 27798篇 |
2010年 | 22680篇 |
2009年 | 18297篇 |
2008年 | 23097篇 |
2007年 | 25614篇 |
2006年 | 11337篇 |
2005年 | 12137篇 |
2004年 | 11629篇 |
2003年 | 11766篇 |
2002年 | 11161篇 |
2001年 | 20087篇 |
2000年 | 20236篇 |
1999年 | 15855篇 |
1998年 | 5611篇 |
1997年 | 6106篇 |
1996年 | 5833篇 |
1995年 | 5417篇 |
1994年 | 5324篇 |
1993年 | 5484篇 |
1992年 | 13453篇 |
1991年 | 13287篇 |
1990年 | 12638篇 |
1989年 | 12424篇 |
1988年 | 11353篇 |
1987年 | 10989篇 |
1986年 | 10256篇 |
1985年 | 10203篇 |
1984年 | 8577篇 |
1983年 | 7406篇 |
1982年 | 5711篇 |
1981年 | 5087篇 |
1980年 | 4884篇 |
1979年 | 8037篇 |
1978年 | 6433篇 |
1977年 | 5859篇 |
1976年 | 5519篇 |
1975年 | 6060篇 |
1974年 | 6245篇 |
1973年 | 6168篇 |
1972年 | 6170篇 |
1971年 | 5696篇 |
1970年 | 4276篇 |
1969年 | 4108篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
R A Harkness G M McCreanor J Allsop D H Snow R C Harris P O Rossdale J C Ousey 《Comparative biochemistry and physiology. B, Comparative biochemistry》1990,97(3):591-596
1. Plasma hypoxanthine and xanthine concentrations are very low in the horse and low in rat, mouse and greyhound compared to concentrations in beagles, man, sheep and rabbit. 2. Activities in erythrocytes of the main enzyme metabolizing hypoxanthine, hypoxanthine phosphori-bosyltransferase, show a similar pattern (Tax et al., 1976, Comp. Biochem. Physiol. 54B, 209-212); thus low activities have been found where plasma concentrations were low. 3. Hypoxanthine phosphoribosyltransferase activities in horse tissue other than erythrocytes are similar to those in man and rabbit with high activities in brain; this enzyme may therefore be functionally important in equine brain. 相似文献
993.
Dry Heat Inactivation of Bacillus subtilis var. niger Spores as a Function of Relative Humidity 总被引:2,自引:2,他引:0 下载免费PDF全文
Dry heat sterilization of Bacillus subtilis var. niger spores at 105 C is enhanced in the relative humidity range 0.03 to 0.2%. D-values of 115 and 125 C are predicted by a kinetic model with parameters set from 105 C data. These predictions are compared to observations. 相似文献
994.
The differentiation of spermatids in the marmoset (Callithrix jacchus, n = 9) testis is described here at the light-microscopic level employing serial semithin sections. The definition of 8 different phases of spermiogenesis, i.e. the formation of spermatids, is based upon the changes in the development of nucleus, acrosome and flagellum. 相似文献
995.
996.
997.
998.
Andrew Leask 《Journal of cell communication and signaling》2010,4(1):73-74
Connective tissue growth factor (CTGF/CCN2) is overexpressed in diabetes. Diabetic rats possess myocardial and cardiomyocyte hypertrophy. In a recent report, Wang and colleagues (Am J Physiol Cell Physiol. 2009 Jul 22. [Epub ahead of print]) show that CCN2 directly mediates cardiomyocyte hypertrophy as well as that induced by high glucose and fatty acid. CCN2 acted via the TrkA receptor. These data are the subject of this commentary, and emphasize that CCN2 may be an excellent target for therapy in diabetes. 相似文献
999.
1000.
R D Gavriliaka N A Semina L I Fiks S V Shabalina N V Tsvetkova 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1985,(1):45-48
ELISA is used for detecting the soluble staphylococcal antigen in patients with purulent septic infections. The optimum conditions for the assay have been established: the dose of staphylococcal gamma globulin for plate sensitization should be 5.0-10.0 micrograms/ml, the pH of the buffer solution 9.6-10.0, the time and temperature of incubation 18-20 hours at 4 degrees C or 5 hours at 37 degrees C. The possibility of using plates manufactured in the USSR has been shown. The sensitivity of the above diagnostic test system is 0.005 microgram/ml. 相似文献