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   333篇
  免费   30篇
  2023年   3篇
  2022年   3篇
  2021年   6篇
  2020年   5篇
  2019年   5篇
  2018年   12篇
  2017年   8篇
  2016年   8篇
  2015年   15篇
  2014年   13篇
  2013年   20篇
  2012年   23篇
  2011年   24篇
  2010年   19篇
  2009年   11篇
  2008年   16篇
  2007年   12篇
  2006年   17篇
  2005年   22篇
  2004年   15篇
  2003年   11篇
  2002年   12篇
  2001年   7篇
  2000年   6篇
  1999年   13篇
  1998年   2篇
  1997年   6篇
  1996年   5篇
  1995年   3篇
  1994年   1篇
  1993年   2篇
  1992年   2篇
  1991年   5篇
  1990年   2篇
  1989年   2篇
  1988年   3篇
  1987年   2篇
  1986年   1篇
  1985年   1篇
  1984年   3篇
  1983年   1篇
  1980年   1篇
  1978年   3篇
  1977年   3篇
  1976年   1篇
  1974年   2篇
  1973年   1篇
  1972年   1篇
  1968年   3篇
  1964年   1篇
排序方式: 共有363条查询结果,搜索用时 0 毫秒
361.
The effect of thyroid hormone therapy (L-T4 or L-T3) on plasma immunoreactive insulin-like growth factor I (somatomedin C, Sm-C) concentrations was studied in 8 normal controls, 14 primary hypothyroid subjects and in 7 patients with endemic cretinism. In normals basal levels of Sm-C (1.56 +/- 0.77 U/ml) increased to (2.46 +/- 1.0 U/ml; L-T4) and to (2.9 +/- 0.95 U/ml; L-T3). Plasma Sm-C basal levels were significantly lower in primary hypothyroid subjects (0.81 +/- 0.48 U/ml) and increased to 2.54 +/- 1.43 U/ml (L-T4) and to 2.16 +/- 0.83 U/ml (L-T3). A significant and positive correlation (r = 0.56) was found between Sm-C and serum T4 and T3 concentrations. Plasma Sm-C concentrations in endemic cretinism were initially normal in 4 patients, but low in the remaining 3 (mean +/- SD: 1.18 +/- 0.63 U/ml) and did not increase after 12 months (1.34 +/- 0.61 U/ml) or 18 months (1.01 +/- 0.43 U/ml) of L-T4 and L-T3 therapy. Plasma T4 levels and free T4 increased considerably in EC after therapy with a significant decrease in the previously elevated plasma TSH concentrations. The subnormal response of plasma Sm-C during effective thyroid thyroid hormone therapy could be an additional factor involved in growth failure of endemic cretins.  相似文献   
362.
The effect of papaverine at the time of starting a post-ischemic acute renal failure in rats has been studied. Papaverine administration increases diuresis and reduces serum urea and creatinine levels. The primary role of hemodynamic disorders as responsible for the diminished glomerular filtration rate is supported by the reduced severity of acute renal failure when this vasodilator agent is administered.  相似文献   
363.
The complex geological history of the western Mediterranean region conceals the interpretation of the evolutionary history of its current fauna, as similar distribution patterns may have very different temporal and geographic origins. Particularly intriguing are some subterranean species in islands, which origin is usually difficult to interpret as their strongly modified morphologies obscure their relationships. We studied subterranean taxa and their likely relatives of two groups of ground beetles in the western Mediterranean: the Duvalius lineage (“isotopic” Trechini) and Molopina (Pterostichini). We included specimens from the islands of Mallorca, Sardinia and Sicily, plus mainland Europe and North Africa. Phylogenetic relationships were reconstructed with a combination of mitochondrial and nuclear data, and divergence dates were estimated with Bayesian methods using the same a priori molecular evolutionary rates for the same gene fragments in the two groups. In the Duvalius lineage, the subgenus Trechopsis, including all the highly modified cave or nivicolous species, was found to be polyphyletic: the species from Mallorca was found to be of Pleistocene origin and sister to the less modified species of subgenus Duvalius from the same island, whereas the Algerian species of Trechopsis were, on the contrary, related to the Sicilian Duvalius, indicating a northern colonisation route during the late Pliocene. Molopina was divided into three main lineages: the genera Abax, Percus, and the Molops groups of genera. The basal diversification of the latter was dated within a temporal window (35–25 Ma) fully congruent with the tectonic opening of the western Mediterranean basin and included six main lineages with uncertain relationships among them: the epigean genera (a) Molops and (b) Tanythrix; and the subterranean (c) Typhlochoromus (Eastern Alps), (d) Speomolops (Sardinia), (e) Henrotius (Mallorca) and (f) a strongly supported clade including the Pyrenean genera Zariquieya, Oscadytes and Molopidius. Despite the similar distribution of some of their subterranean taxa, the two studied groups show a strongly contrasting origin and mode of diversification. While the Duvalius lineage had a recent origin, with complex colonisation patterns and widespread morphological convergence among the subterranean species, the subterranean Molopina had an ancient vicariant origin resulting from the tectonic opening of the western Mediterranean basin.  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