首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   192篇
  免费   10篇
  国内免费   1篇
林业   7篇
农学   10篇
基础科学   3篇
  29篇
综合类   30篇
农作物   11篇
水产渔业   7篇
畜牧兽医   83篇
植物保护   23篇
  2023年   2篇
  2022年   2篇
  2021年   2篇
  2020年   1篇
  2019年   2篇
  2018年   3篇
  2017年   3篇
  2016年   5篇
  2015年   4篇
  2014年   7篇
  2013年   10篇
  2012年   10篇
  2011年   18篇
  2010年   6篇
  2009年   6篇
  2008年   9篇
  2007年   11篇
  2006年   3篇
  2005年   5篇
  2004年   6篇
  2003年   8篇
  2002年   1篇
  2001年   4篇
  2000年   4篇
  1999年   4篇
  1998年   5篇
  1997年   6篇
  1996年   5篇
  1995年   5篇
  1993年   5篇
  1992年   4篇
  1991年   2篇
  1990年   7篇
  1989年   4篇
  1988年   3篇
  1987年   1篇
  1986年   3篇
  1985年   5篇
  1984年   3篇
  1983年   1篇
  1982年   1篇
  1979年   1篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1965年   1篇
  1963年   2篇
排序方式: 共有203条查询结果,搜索用时 8 毫秒
201.
Kao SY  Su JH  Hwang TL  Sheu JH  Wen ZH  Wu YC  Sung PJ 《Marine drugs》2011,9(9):1534-1542
Two new metabolites, including a lindenane-type sesquiterpenoid, menelloide C (1), and a germacrane-type sesquiterpenoid, menelloide D (2), were isolated from a Formosan gorgonian coral identified as Menella sp. The structures of 1 and 2 were established by spectroscopic methods and 2 displayed a weak inhibitory effect on the release of elastase by human neutrophils.  相似文献   
202.
Kao CY  Su JH  Lu MC  Hwang TL  Wang WH  Chen JJ  Sheu JH  Kuo YH  Weng CF  Fang LS  Wen ZH  Sung PJ 《Marine drugs》2011,9(8):1319-1331
Five new cembrane-type diterpenoids, lobocrassins A-E (1-5), were isolated from the soft coral Lobophytum crassum. The structures of cembranes 1-5 were established by spectroscopic and chemical methods and by comparison of the spectral data with those of known cembrane analogues. Lobocrassin A (1) is the first cembranoid possessing an α-chloromethyl-α-hydroxy-γ-lactone functionality and is the first chlorinated cembranoid from soft corals belonging to the genus Lobophytum. Lobocrassins B (2) and C (3) were found to be the stereoisomers of the known cembranes, 14-deoxycrassin (6) and pseudoplexaurol (7), respectively. Lobocrassin B (2) exhibited modest cytotoxicity toward K562, CCRF-CEM, Molt4, and HepG2 tumor cells and displayed significant inhibitory effects on the generation of superoxide anion and the release of elastase by human neutrophils.  相似文献   
203.
The aim of this study was to describe the changes in the resistance index (RI) and systolic/diastolic ratio ( S / D ) of the uterine arteries during mid-pregnancy abortion induction in the dog. Sixteen 30–35 day pregnant bitches were randomly assigned to either a pharmacological protocol to interrupt gestation (n = 8) or were used as untreated control group (n = 8). Doppler assessments of uterine arteries blood flow were carried out before the initiation of the protocol and then every other day up to abortion (treated group) or parturition (control group). All treated bitches aborted 6 ± 1.2 days after initiation of the treatment (while none of the non-treated bitches aborted). Pre-treatment RI and S / D did not differ between groups (p > 0.2) while average post-treatment indexes were (mean ± SD): 0.62 ± 0.1 vs 0.53 ± 0.1 (p < 0.01) and 2.96 ± 0.9 vs 2.23 ± 0.3 (p = 0.01), for the treated and non-treated group respectively. Correlations between days to abortion and RI or S / D were 0.75 (p < 0.01) and 0.79 (p < 0.01) and, −0.78 (p < 0.01) and −0.73 (p < 0.01) for the treated and non-treated groups respectively. In the treated group, correlations between serum progesterone (P4) concentrations and RI and S / D were −0.76 (p < 0.01) and −0.59 (p < 0.01) respectively. It is concluded that, during induction of abortion, RI and S / D of uterine arteries progressively increased while P4 decreased.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号