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   6711篇
  免费   607篇
  国内免费   3篇
  2023年   30篇
  2022年   63篇
  2021年   159篇
  2020年   72篇
  2019年   123篇
  2018年   139篇
  2017年   113篇
  2016年   198篇
  2015年   341篇
  2014年   438篇
  2013年   534篇
  2012年   579篇
  2011年   572篇
  2010年   365篇
  2009年   342篇
  2008年   444篇
  2007年   428篇
  2006年   417篇
  2005年   387篇
  2004年   342篇
  2003年   318篇
  2002年   307篇
  2001年   49篇
  2000年   50篇
  1999年   71篇
  1998年   63篇
  1997年   42篇
  1996年   35篇
  1995年   36篇
  1994年   31篇
  1993年   30篇
  1992年   26篇
  1991年   14篇
  1990年   15篇
  1989年   17篇
  1988年   9篇
  1987年   18篇
  1986年   16篇
  1985年   9篇
  1983年   12篇
  1981年   3篇
  1980年   13篇
  1979年   7篇
  1978年   8篇
  1977年   9篇
  1975年   5篇
  1974年   4篇
  1972年   2篇
  1970年   2篇
  1965年   2篇
排序方式: 共有7321条查询结果,搜索用时 15 毫秒
71.
Detection of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is a crucial tool for fighting the COVID‐19 pandemic. This dataset brief presents the exploration of a shotgun proteomics dataset acquired on SARS‐CoV‐2 infected Vero cells. Proteins from inactivated virus samples were extracted, digested with trypsin, and the resulting peptides were identified by data‐dependent acquisition tandem mass spectrometry. The 101 peptides reporting for six viral proteins were specifically analyzed in terms of their analytical characteristics, species specificity and conservation, and their proneness to structural modifications. Based on these results, a shortlist of 14 peptides from the N, S, and M main structural proteins that could be used for targeted mass‐spectrometry method development and diagnostic of the new SARS‐CoV‐2 is proposed and the best candidates are commented.  相似文献   
72.
73.
Self‐incompatibility (SI) is the main mechanism that favors outcrossing in plants. By limiting compatible matings, SI interferes in fruit production and breeding of new cultivars. In the Oleeae tribe (Oleaceae), an unusual diallelic SI system (DSI) has been proposed for three distantly related species including the olive (Olea europaea), but empirical evidence has remained controversial for this latter. The olive domestication is a complex process with multiple origins. As a consequence, the mixing of S‐alleles from two distinct taxa, the possible artificial selection of self‐compatible mutants and the large phenological variation of blooming may constitute obstacles for deciphering SI in olive. Here, we investigate cross‐genotype compatibilities in the Saharan wild olive (O. e. subsp. laperrinei). As this taxon was geographically isolated for thousands of years, SI should not be affected by human selection. A population of 37 mature individuals maintained in a collection was investigated. Several embryos per mother were genotyped with microsatellites in order to identify compatible fathers that contributed to fertilization. While the pollination was limited by distance inside the collection, our results strongly support the DSI hypothesis, and all individuals were assigned to two incompatibility groups (G1 and G2). No self‐fertilization was observed in our conditions. In contrast, crosses between full or half siblings were frequent (ca. 45%), which is likely due to a nonrandom assortment of related trees in the collection. Finally, implications of our results for orchard management and the conservation of olive genetic resources are discussed.  相似文献   
74.
75.
According to theories on cave adaptation, cave organisms are expected to develop a lower metabolic rate compared to surface organisms as an adaptation to food scarcity in the subterranean environments. To test this hypothesis, we compared the oxygen consumption rates of the surface and subterranean populations of a surface‐dwelling species, the newt Calotriton asper, occasionally found in caves. In this study, we designed a new experimental setup in which animals with free movement were monitored for several days in a respirometer. First, we measured the metabolic rates of individuals from the surface and subterranean populations, both maintained for eight years in captivity in a natural cave. We then tested individuals from these populations immediately after they were caught and one year later while being maintained in the cave. We found that the surface individuals that acclimated to the cave significantly reduced their oxygen consumption, whereas individuals from the subterranean population maintained in the cave under a light/dark cycle did not significantly modify their metabolic rates. Second, we compared these metabolic rates to those of an obligate subterranean salamander (Proteus anguinus), a surface aquatic Urodel (Ambystoma mexicanum), and a fish species (Gobio occitaniae) as references for surface organisms from different phyla. As predicted, we found differences between the subterranean and surface species, and the metabolic rates of surface and subterranean C. asper populations were between those of the obligate subterranean and surface species. These results suggest that the plasticity of the metabolism observed in surface C. asper was neither directly due to food availability in our experiments nor the light/dark conditions, but due to static temperatures. Moreover, we suggest that this adjustment of the metabolic level at a temperature close to the thermal optimum may further allow individual species to cope with the food limitations of the subterranean environment.  相似文献   
76.
77.
Journal of Applied Phycology - In recent years diatoms have emerged as a major algal source for the production of bioactive compounds. Marine diatoms grow quickly and can store high amount of...  相似文献   
78.
79.
80.
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