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   84篇
  免费   16篇
  2015年   1篇
  2014年   1篇
  2013年   5篇
  2012年   2篇
  2011年   4篇
  2010年   3篇
  2009年   4篇
  2008年   1篇
  2007年   5篇
  2006年   3篇
  2004年   1篇
  2003年   1篇
  2002年   3篇
  2001年   5篇
  1999年   1篇
  1998年   2篇
  1996年   3篇
  1995年   1篇
  1994年   2篇
  1993年   1篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1980年   1篇
  1978年   1篇
  1975年   1篇
  1974年   3篇
  1973年   1篇
  1972年   3篇
  1971年   2篇
  1970年   1篇
  1967年   1篇
  1966年   1篇
  1964年   1篇
  1958年   1篇
  1957年   2篇
  1956年   1篇
  1954年   1篇
  1952年   1篇
  1951年   4篇
  1950年   3篇
  1947年   2篇
  1945年   2篇
  1943年   1篇
  1942年   4篇
  1941年   1篇
  1940年   3篇
  1939年   1篇
  1938年   2篇
  1936年   1篇
排序方式: 共有100条查询结果,搜索用时 31 毫秒
1.
2.
Thirty one families with Alport syndrome including 3 families with associated syndromes were studied. The location of the COL4A5 gene, responsible for the Alport syndrome, was determined by linkage analysis with eight probes of the Xq arm and by a radiation hybrid panel. Concordant data indicated the localization of the Alport gene between DXS17 and DXS11. Four deletions and one single base mutation of the COL4A5 gene were detected. Homogeneity tests failed to show any evidence of genetic heterogeneity superimposed on clinical heterogeneity for ophthalmic signs and end-stage renal disease age.  相似文献   
3.
Mitotic and meiotic chromosomes of the Antarctic lysianassoid amphipod Waldeckia obesa are described. The modal chromosome number is n = 25 and 2n = 50. The potential applications of cytogenetical studies in this group are discussed.  相似文献   
4.
5.
Joël Broyer 《Bird Study》2013,60(2):141-150
Capsule Mowing postponement in 25% of a meadow system may lead to improved but instable population dynamics in meadow birds.

Aim To monitor the long‐term effects of mowing postponement on the abundance and territory density of meadow passerines in 25% of a 3000‐ha hay‐meadow area in the Saône Valley (eastern France).

Methods From 1993 to 2009, passerine abundance was measured annually in 78 plots using point counts and territory density was assessed in two study areas by Territory Mapping.

Results The programme of mowing postponement led to substantially increased passerine abundance and territory density, with the highest increase detected in Whinchats Saxicola rubetra. No positive trend was observed in Corn Buntings Emberiza calandra. Immediately after the increase in abundance, bird distribution within the study area was not influenced by the timing of mowing. The hatching success, assessed by the systematic observation of food carrying, was negatively influenced by early mowing (<40% recorded when >60% of the meadow area was already harvested on 1 July) or, in late mown areas, by high meadow passerine territory density (<40% when territory density was >10 per 10 ha). Hatching rate was usually higher in Whinchats than in Corn Buntings.

Conclusion By improving meadow passerine breeding outputs and density, mowing postponement led to instable population dynamics with dominance of certain species and density‐dependent breeding success.  相似文献   
6.

Background  

Peripheral tissue inflammation initiates hyperalgesia accompanied by tissue acidosis, nociceptor activation, and inflammation mediators. Recent studies have suggested a significantly increased expression of acid-sensing ion channel 3 (ASIC3) in both carrageenan- and complete Freund's adjuvant (CFA)-induced inflammation. This study tested the hypothesis that acupuncture is curative for mechanical hyperalgesia induced by peripheral inflammation.  相似文献   
7.
A number of native and exotic animal species show dramatic population increases in terms of both numbers and geographic range. Understanding the habitat selection processes behind such increases is crucial to implement adequate management measures. Mute swan (Cygnus olor) populations have experienced a tremendous demographic and geographic expansion in Western Europe during the twentieth century, colonizing a wide variety of aquatic habitats. We aimed at assessing how swans select nesting sites during the pre-laying and laying periods on medium to large fishponds (from 10 to 50 ha) in Eastern France, while accounting for detectability biases and testing for the effects of fishpond spatial configuration, vegetation resources, human disturbance and habitat management. Our results demonstrate that the mute swan is a non-selective species regarding its nesting habitat among such fishponds, using these independently from the parameters considered although fishpond characteristics varied. Although mute swan is one of the least cryptic Anatidae, owing to its white colour and large size, detection of breeding pairs remained imperfect for each over several sampling occasions. However, because we repeated the sampling sessions, detection of swan pairs by the end of the monitoring period was as high as 0.94. These results are consistent with previous assertions that the mute swan is a species of high ecological plasticity, which may partly explain its recent colonization rates. Given that even swan breeding events were imperfectly detected on each occasion, we highlight the fact that most studies of breeding ducks (which are more cryptic) would be considerably improved by better considering detection biases.  相似文献   
8.

Background  

Owing to rapid expansion of protein structure databases in recent years, methods of structure comparison are becoming increasingly effective and important in revealing novel information on functional properties of proteins and their roles in the grand scheme of evolutionary biology. Currently, the structural similarity between two proteins is measured by the root-mean-square-deviation (RMSD) in their best-superimposed atomic coordinates. RMSD is the golden rule of measuring structural similarity when the structures are nearly identical; it, however, fails to detect the higher order topological similarities in proteins evolved into different shapes. We propose new algorithms for extracting geometrical invariants of proteins that can be effectively used to identify homologous protein structures or topologies in order to quantify both close and remote structural similarities.  相似文献   
9.
10.
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