全文获取类型
收费全文 | 1922篇 |
免费 | 67篇 |
国内免费 | 53篇 |
出版年
2023年 | 18篇 |
2022年 | 23篇 |
2021年 | 20篇 |
2020年 | 31篇 |
2019年 | 44篇 |
2018年 | 39篇 |
2017年 | 29篇 |
2016年 | 31篇 |
2015年 | 29篇 |
2014年 | 67篇 |
2013年 | 125篇 |
2012年 | 51篇 |
2011年 | 108篇 |
2010年 | 64篇 |
2009年 | 79篇 |
2008年 | 66篇 |
2007年 | 90篇 |
2006年 | 66篇 |
2005年 | 70篇 |
2004年 | 46篇 |
2003年 | 58篇 |
2002年 | 33篇 |
2001年 | 38篇 |
2000年 | 21篇 |
1999年 | 31篇 |
1998年 | 20篇 |
1997年 | 21篇 |
1996年 | 18篇 |
1995年 | 17篇 |
1994年 | 22篇 |
1993年 | 14篇 |
1991年 | 15篇 |
1990年 | 13篇 |
1989年 | 22篇 |
1988年 | 10篇 |
1987年 | 12篇 |
1986年 | 11篇 |
1985年 | 40篇 |
1984年 | 57篇 |
1983年 | 39篇 |
1982年 | 44篇 |
1981年 | 42篇 |
1980年 | 42篇 |
1979年 | 44篇 |
1978年 | 49篇 |
1977年 | 38篇 |
1976年 | 27篇 |
1975年 | 42篇 |
1974年 | 50篇 |
1973年 | 30篇 |
排序方式: 共有2042条查询结果,搜索用时 343 毫秒
81.
82.
83.
84.
The metabolism of testosterone (T) was studied in normal adult male rats using a constant infusion of trace amounts of the 3H-steroid into a tail vein for 3 h in order to attain a state of equilibrium. Samples of plasma, liver, kidney, prostate, seminal vesicles and muscle were analysed for 3H-testosterone, 3H-5alpha-dihydrotestosterone (5alphaDHT) and 3H-5alpha-androstanediol (Adiol). When compared to the 3H-T level in plasma there were high levels of 3H-T in kidney and of 3H-5alphaDHT in prostate and seminal vesicles. Intraperitoneal estradiol valerate administration (100 mug/day) for 4 days decreased and 3H-5alphaDHT levels in the prostate and seminal vesicles. The estrogen administration increased the T metabolic clearance rate from 17.5 1/24 h/100 g body wt to 22.6 1/24 h/100 g body wt. 相似文献
85.
86.
A series of fatty acid ethyl esters ranging from C14 to C24 was isolated from a hexane extract of the liverwort Conocephalum conicum, these esters accounted for 77% of the extract. The ethyl esters consisting of even-numbered fatty acids were predominant and ethyl palmitate was the major constituent. 相似文献
87.
A radioimmunoassay for plasma estradiol-17β was developed using polyethylene glycol to separate free from antibody-bound hormone. Specificity for estradiol-17β was achieved by a modified celite microcolunm procedure in which estradiol was.separated from interfering estrogens, including estrone. Using trace 3H-estradiol to monitor procedural losses, the method was shown to be sensitive and accurate. Intra- and inter-assay coefficient of variation of the method was 8.7 and 10.6%, respectively. Polyethylene glycol used for antibody precipitation appears to be a generally applicable method for steroid hormone radioimmunoassays. The simplicity, precision and rapid analysis, coupled with its lack of time dependence and ease in automation, makes this a convenient and practical method. 相似文献
88.
89.
90.
Chemical investigation of Saussurea licentiana led to the isolation of ten compounds, and their structures were identified to be dia-aurantiamide acetate (1), (+)-pinoresinol 4-O-β-D-glucoside (2), encelin (3), apigenin (4), luteolin (5), jaceosidin (6), luteolin -7-O-β-D- glucopyranoside (7), α-amyrin (8), β-amyrin (9), taraxasterol (10) on the basis of mass and NMR spectra. This is the first report on the occurrence of compounds 1, and 2 in the genus Saussurea while 1 is reported for the first time from Asteraceae. This work also represents the first phytochemical work on the whole plants of S. licentiana. 相似文献