全文获取类型
收费全文 | 10506篇 |
免费 | 1015篇 |
国内免费 | 19篇 |
出版年
2022年 | 78篇 |
2021年 | 198篇 |
2020年 | 88篇 |
2019年 | 112篇 |
2018年 | 153篇 |
2017年 | 111篇 |
2016年 | 229篇 |
2015年 | 495篇 |
2014年 | 516篇 |
2013年 | 659篇 |
2012年 | 829篇 |
2011年 | 786篇 |
2010年 | 473篇 |
2009年 | 371篇 |
2008年 | 593篇 |
2007年 | 592篇 |
2006年 | 542篇 |
2005年 | 462篇 |
2004年 | 461篇 |
2003年 | 409篇 |
2002年 | 393篇 |
2001年 | 197篇 |
2000年 | 143篇 |
1999年 | 114篇 |
1998年 | 127篇 |
1997年 | 89篇 |
1996年 | 92篇 |
1995年 | 65篇 |
1994年 | 94篇 |
1993年 | 74篇 |
1992年 | 102篇 |
1991年 | 81篇 |
1990年 | 100篇 |
1989年 | 96篇 |
1988年 | 71篇 |
1987年 | 71篇 |
1986年 | 61篇 |
1985年 | 83篇 |
1984年 | 75篇 |
1983年 | 73篇 |
1982年 | 90篇 |
1981年 | 58篇 |
1980年 | 53篇 |
1979年 | 65篇 |
1978年 | 52篇 |
1977年 | 58篇 |
1976年 | 66篇 |
1975年 | 69篇 |
1974年 | 64篇 |
1973年 | 67篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
33.
34.
35.
36.
Eric Hsu 《Curtis's Botanical Magazine》2005,22(4):200-204
Summary. Saruma henryi Oliver is described and illustrated. The distribution, ecology, taxonomy and cultural requirements of this unusual member of the Aristolochiaceae are discussed. 相似文献
37.
This study examined the flocculation behavior of two Saccharomyces cerevisiae strains expressing either Flo1 (LCC1209) genotype or NewFlo (LCC125) phenotype in a laminar flow field by measurement of the fundamental flocculation parameter, the orthokinetic capture coefficient. This orthokinetic capture coefficient was measured as a function of shear rate (5.95-223 s(-1)) and temperature (5-45 degrees C). The capture coefficients of these suspensions were directly proportional to the inverse of shear rate, and exhibited an increase as the temperature was increased to 45 degrees C. The capture coefficient of pronase-treated cells was also measured over similar shear rate and temperature range. A theory, which predicts capture coefficient values due to zymolectin interactions, was simplified from that developed by Long et al. [Biophys. J. 76: (1999) 1112]. This new modified theory uses estimates of: (1) cell wall densities of zymolectins and carbohydrate ligands; (2) cell wall collision contact area; and (3) the forward rate coefficient of binding to predict theoretical capture coefficients. A second model that involves both zymolectin interactions and DLVO forces was used to describe the phenomenon of yeast flocculation at intermediate shear ranges, to explain yeast flocculation in laminar flow. 相似文献
38.
Blastomycosis was fatal to a wild wolf in Minnesota, and serologic evidence of blastomycosis was found in a Wisconsin wolf. No unusual movements were detected in the Minnesota animal from October 1983 through October 1985. However, by early December 1985, this wolf was weak and debilitated, and it perished on 14 December after approaching a human residence. 相似文献
39.
40.
Yohimbine increases plasma insulin concentrations of dogs 总被引:1,自引:0,他引:1
W H Hsu D D Schaffer M H Pineda 《Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)》1987,184(3):345-349
Recent evidence suggests that catecholamines inhibit insulin release by stimulating alpha 2-adrenoreceptors in beta-cells of the pancreatic islets. In the present study, iv injections of 0.1 and 0.3 mg/kg of yohimbine, an alpha 2-adrenoreceptor antagonist, resulted in increased plasma insulin and decreased plasma glucose concentrations in the dog. The use of alpha 2-adrenoreceptor antagonists may be of value in non-insulin-dependent diabetic patients by counteracting the inhibitory influence of endogenous catecholamines. 相似文献