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   426篇
  免费   25篇
  2022年   9篇
  2021年   10篇
  2020年   7篇
  2019年   12篇
  2018年   12篇
  2017年   7篇
  2016年   14篇
  2015年   24篇
  2014年   21篇
  2013年   31篇
  2012年   26篇
  2011年   36篇
  2010年   25篇
  2009年   18篇
  2008年   24篇
  2007年   24篇
  2006年   12篇
  2005年   10篇
  2004年   14篇
  2003年   10篇
  2002年   13篇
  2001年   5篇
  2000年   2篇
  1999年   4篇
  1998年   6篇
  1997年   5篇
  1996年   3篇
  1995年   1篇
  1994年   5篇
  1993年   3篇
  1991年   5篇
  1990年   1篇
  1989年   3篇
  1988年   3篇
  1987年   2篇
  1986年   4篇
  1985年   5篇
  1984年   3篇
  1983年   3篇
  1982年   2篇
  1980年   3篇
  1979年   3篇
  1977年   4篇
  1976年   3篇
  1975年   4篇
  1974年   3篇
  1973年   3篇
  1971年   1篇
  1968年   1篇
  1967年   1篇
排序方式: 共有451条查询结果,搜索用时 203 毫秒
1.

Background  

Anthropogenic habitat modifications have led to the extinction of many species and have favoured the expansion of others. Nonetheless, the possible role of humans as a diversifying force in vertebrate evolution has rarely been considered, especially for species with long generation times. We examine the influence that humans have had on the colonization and phenotypic and genetic differentiation of an insular population of a long-lived raptor species, the Egyptian vulture (Neophron percnopterus).  相似文献   
2.
The effectiveness and acceptability of Alfaprostol (an analog of PGF2 alpha) in inducing labor were assessed in 20 pregnant women at term. All subjects had no spontaneous uterine activity before treatment and the mean (M +/- SE) Bishop score was 2.45 +/- 0.21. The drug was administered by vaginal route at the dose of 10 mg every 3 hours. Regular uterine contractions appeared in all patients and delivery occurred in 85% of the patients after a mean time of 9h50min +/- 0h55min following the start of treatment. The mean dose of Alfaprostol utilized to achieve delivery was 29.4 +/- 2.0 mg. No major side effects were noted in the mothers and their fetuses at any time during treatment. Two patients exhibited vomiting. The Apgar score of all newborns at birth was 8 or more. These results suggest the usefulness of Alfaprostol to induce labor in pregnant women at term, as it has oxytocic activity without adverse effects on either the mother or the fetus.  相似文献   
3.
4.
5.
Summary In the testis of Esox lucius at the time of spermiation, activity of cyclic adenosine 3,5-monophosphate (cAMP) was immunocytochemically localized at the level of the Sertoli cells. In these cells adenylate cyclase activity was also ultracytochemically demonstrated by using adenylyl imidodiphosphate as a substrate. Reaction products of adenylate cyclase were primarily detectable on the basal and adluminal plasma membranes and on the surface of protrusions of the cell body into the lumen.  相似文献   
6.
7.
8.
The conformational properties of spantide [(D-Arg, D-Trp, Leu) substance P] have been studied by fluorescence, CD, and nmr techniques. The fluorescence, CD, and nmr parameters in different solvents and in a micellar environment (SDS) are compared with the data collected for bombesin. A preliminary investigation on [D-Pro] spantide is also reported.  相似文献   
9.
Plant and Soil - The ecological study of root systems lags behind the understanding of the aboveground components of plant communities, mainly due to methodological challenges. As ecological root...  相似文献   
10.
Abstract

Total Hip Arthroplasty requires pre-surgical evaluation between un-cemented and cemented prostheses. A Patient with intra-operative periprosthetic fracture and another with a successful outcome were recruited, and their finite element models were constructed by processing CT data, assuming elastic-plastic behavior of the bone as function of the local density. To resemble the insertion of the prosthesis into the femur, a fictitious thermal dilatation is applied to the broach volume. Strain-based fracture risk factor is estimated, depicting results in terms of the total mechanical strain expressed using a simple “traffic lights” color code to provide immediate, concise, and intelligible pre-operative information to surgeons.  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