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   322篇
  免费   11篇
  2013年   11篇
  2012年   3篇
  2011年   4篇
  2010年   3篇
  2009年   6篇
  2008年   3篇
  2007年   5篇
  2006年   6篇
  2005年   6篇
  2004年   4篇
  1998年   6篇
  1997年   5篇
  1996年   8篇
  1995年   3篇
  1994年   4篇
  1993年   5篇
  1992年   4篇
  1991年   6篇
  1990年   5篇
  1989年   6篇
  1988年   6篇
  1987年   6篇
  1986年   3篇
  1985年   4篇
  1984年   10篇
  1983年   4篇
  1982年   3篇
  1980年   5篇
  1979年   8篇
  1978年   6篇
  1977年   7篇
  1975年   11篇
  1974年   3篇
  1973年   8篇
  1972年   12篇
  1971年   12篇
  1970年   4篇
  1969年   3篇
  1968年   5篇
  1965年   4篇
  1958年   9篇
  1957年   12篇
  1956年   10篇
  1955年   6篇
  1953年   11篇
  1952年   8篇
  1951年   5篇
  1950年   3篇
  1948年   3篇
  1909年   2篇
排序方式: 共有333条查询结果,搜索用时 62 毫秒
331.
THE author has already, in a brief communication (Journ. Linn. Soc. no. 67, vol. xiii. p. 115), given a preliminary notice of two new species of Lepidoptera from Malacca, and mentioned the donor and circumstances which have enabled him to draw up an extended list, with annexed remarks on geographical distribution. It is only necessary to add that the paper, with figures of the new and more remarkable forms, will subsequently appear in the Society's ‘Transactions’  相似文献   
332.
Leaf reflectance responses to increased ozone and precipitationacidity were determined at visible (400–720 nm) and infra-red(720–2500 nm) wavelengths for field-grown seedlings ofloblolly pine (Pinus taeda L.). Treatments were maintained continuouslyfrom 3 April to 3 November. In a relatively ozone-sensitivevariety of pine, increased ozone decreased visible and infra-redreflectance by late May. By late August, continued exposureto ozone increased visible and infra-red reflectance. As oflate November, ozone at 17ambient or greater concentrationshad increased visible reflectance substantially in an ozone-insensitiveas well as the ozone-sensitive variety. Acidic precipitationdecreased visible and infra-red reflectances in both varietiesin May and decreased infra-red reflectances in the ozone-sensitivevariety in August, but did not produce significant reflectanceresponses in November. Visible reflectance responses to ozoneand acidic precipitation, particularly those near 700 nm, werespectrally similar to reflectance responses reported previouslyfor other deleterious environmental influences. Key words: Pinus taeda, reflectance, ozone, acidic precipitation  相似文献   
333.
There is increasing interest among evolutionary biologists in developmental plasticity. Previously ignored by many as being irrelevant to evolution because a plastic response to an environmental change is not inherited, the current, more positive, view of plasticity focuses on the fact that, although any individual plastic response is nonheritable, the overall pattern of developmental response to environmental variation (i.e. the developmental reaction norm) is heritable and may vary among genotypes within a population. Characters subject to plastic variation, like those that are entirely genetically determined, may vary in continuous, meristic or discrete ways. Of these, the least work has been carried out on meristic variation. In the present study, we contribute to the rectification of this imbalance by examining the plastic response of the number of tentacles in the lophophore of a species of bryozoan, Membranipora membranacea, to three environmental variables: temperature, salinity and food concentration. Because the approach taken was an experimental one, unlike the majority of studies of bryozoan tentacles to date, we are able to make statements about the causality of variation in tentacle number. The main conclusions of the present study are: (1) that plastic responses occur to all three environmental variables; (2) that these are part of a more generalized plastic response in the overall development of the zooids rather than being lophophore‐specific; and (3) that the issue of whether the relevant developmental reaction norms are adaptive or not is an open (and interesting) question. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 104 , 541–551.  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