全文获取类型
收费全文 | 639027篇 |
免费 | 66396篇 |
国内免费 | 602篇 |
出版年
2018年 | 5657篇 |
2016年 | 7398篇 |
2015年 | 9153篇 |
2014年 | 10982篇 |
2013年 | 16167篇 |
2012年 | 18744篇 |
2011年 | 19770篇 |
2010年 | 12882篇 |
2009年 | 11460篇 |
2008年 | 17350篇 |
2007年 | 17949篇 |
2006年 | 17077篇 |
2005年 | 16297篇 |
2004年 | 16068篇 |
2003年 | 15421篇 |
2002年 | 15257篇 |
2001年 | 28470篇 |
2000年 | 29098篇 |
1999年 | 22531篇 |
1998年 | 7387篇 |
1997年 | 7632篇 |
1996年 | 7329篇 |
1995年 | 6908篇 |
1994年 | 6805篇 |
1993年 | 6711篇 |
1992年 | 18150篇 |
1991年 | 17636篇 |
1990年 | 17383篇 |
1989年 | 16855篇 |
1988年 | 15865篇 |
1987年 | 15089篇 |
1986年 | 14020篇 |
1985年 | 14512篇 |
1984年 | 11915篇 |
1983年 | 10243篇 |
1982年 | 7822篇 |
1981年 | 7306篇 |
1980年 | 6717篇 |
1979年 | 11377篇 |
1978年 | 9071篇 |
1977年 | 8336篇 |
1976年 | 8000篇 |
1975年 | 9063篇 |
1974年 | 9819篇 |
1973年 | 9826篇 |
1972年 | 8855篇 |
1971年 | 8100篇 |
1970年 | 7067篇 |
1969年 | 6787篇 |
1968年 | 6361篇 |
排序方式: 共有10000条查询结果,搜索用时 281 毫秒
981.
A serum- and glucocorticoid-regulated 4-kilobase mRNA encodes a cyclooxygenase-related protein. 总被引:21,自引:0,他引:21
M K O'Banion H B Sadowski V Winn D A Young 《The Journal of biological chemistry》1991,266(34):23261-23267
982.
983.
984.
T Barreca R Franceschini C Siani A Cataldi N Francaviglia C Silvestro E Rolandi 《Hormone research》1991,35(6):239-241
Arginine vasopressin (AVP) concentrations were determined in plasma and in cerebrospinal fluid (CSF) in 8 adult male patients suffering from hydrocephalus of various etiologies, before and after intravenous administration of 10 mg metoclopramide. Metoclopramide was able to increase the plasma (2.6 +/- 0.2 ng/l in basal conditions and 6.1 +/- 0.6 ng/l at 30 min) but not the CSF AVP levels. The results suggest that the neurons which secrete AVP into the CSF may be functionally different from those secreting into the peripheral circulation. 相似文献
985.
986.
987.
Georg Steinhauser Johannes H. Sterba Karin Poljanc Max Bichler Karl Buchtela 《Journal of trace elements in medicine and biology》2006,20(3):119-153
In this study, 18 partly commercially available samples of rock salt from Austria, Germany, Pakistan, Poland, Switzerland, and Ukraine were investigated with respect to their content of trace elements using instrumental neutron activation analysis. Elements detected were Al, Ba, Br, Ca, Ce, Cl, Co, Cr, Cs, Eu, Fe, Hf, La, Mn, Na, Rb, Sb, Sc, Sm, Sr, Ta, Tb, Th, and Zn, some of them only in individual cases. An estimation of the bioavailability of these trace elements was performed by dissolving an equivalent of the sodium chloride samples in diluted hydrochloric acid (simulating stomach acid), filtering off the insoluble components, and analyzing the evaporated filtrate. It could be shown that in most cases bioactive trace elements like Fe can be found in rock salt in the form of almost insoluble compounds and are therefore not significantly bioavailable, whereas thorium, for example, was partly bioavailable in two cases. A significant contribution to the recommended daily intake of metal trace elements by using rock salt for nutrition can be excluded. 相似文献
988.
989.
The epididymis of buffalo is differentiated into 6 regions. The head represents the first 3 regions, the body the 4th region and the tail the 5th and 6th region. At 3-30 weeks, the epithelium is simple high columnar with few basal cells in region I, simple low columnar with few basal cells in region II, pseudostratified low columnar in regions III, IV, V, and pseudostratified low columar in region VI. As age advances, the epithelium increases in height and shows a tendency toward advanced pseudostratification. The basal cells are greater in number in regions III, IV and V than in the other regions of the epididymis. The epithelial cells contain stereocilia in region I at 3 weeks and regions III, IV and V at 30 weeks, whereas they are absent in regions II and VI. The tubules in region I are the smallest in diameter while the tubules in region VI have the largest diameter. 相似文献
990.
A method for separation and visualization of the different apolipoprotein B species using 0.2% sodium dodecyl sulfate-1.5% agarose gel electrophoresis and immunoblotting is described. The method is capable of demonstrating the different forms of apolipoprotein B (apo B) in plasma volumes of 10-50 microliters without prior ultracentrifugation. After ultracentrifugation of samples, estimation of the ratio between apo B 48 and apo B 100 is possible by scanning of Coomassie-stained gels or immunoblots. 相似文献