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   108773篇
  免费   9881篇
  国内免费   59篇
  2022年   753篇
  2021年   1792篇
  2020年   1046篇
  2019年   1301篇
  2018年   1681篇
  2017年   1495篇
  2016年   2511篇
  2015年   4245篇
  2014年   4709篇
  2013年   5754篇
  2012年   7567篇
  2011年   7550篇
  2010年   4983篇
  2009年   4441篇
  2008年   6243篇
  2007年   6274篇
  2006年   6035篇
  2005年   5837篇
  2004年   5799篇
  2003年   5496篇
  2002年   5176篇
  2001年   1548篇
  2000年   1308篇
  1999年   1601篇
  1998年   1561篇
  1997年   1165篇
  1996年   1085篇
  1995年   957篇
  1994年   867篇
  1993年   944篇
  1992年   1151篇
  1991年   1010篇
  1990年   993篇
  1989年   925篇
  1988年   850篇
  1987年   773篇
  1986年   693篇
  1985年   778篇
  1984年   921篇
  1983年   713篇
  1982年   784篇
  1981年   760篇
  1980年   657篇
  1979年   621篇
  1978年   586篇
  1977年   561篇
  1976年   474篇
  1975年   438篇
  1974年   481篇
  1973年   364篇
排序方式: 共有10000条查询结果,搜索用时 796 毫秒
101.
102.
103.
We determined the species diversity, blood‐feeding behavior, and host preference of Anopheles mosquitoes in two malaria endemic areas of Tak (Mae Sot District) and Mae Hong Son (Sop Moei District) Provinces, located along the Thai border with Myanmar, during a consecutive two‐year period. Anopheline mosquitoes were collected using indoor and outdoor human‐landing captures and outdoor cow‐baited collections. Mosquitoes were initially identified using morphological characters, followed by the appropriate multiplex AS‐PCR assay for the identification of sibling species within Anopheles (Cellia) complexes and groups present. Real‐time PCR was performed for parasite‐specific detection in mosquitoes (Plasmodium spp. and Wuchereria bancrofti). A total of 7,129 Anopheles females were captured, 3,939 from Mae Sot and 3,190 from Sop Moei, with 58.6% and 37% of all anophelines identified as An. minimus, respectively. All three malaria vector complexes were detected in both areas. One species within the Minimus Complex (An. minimus) was present along with two related species in the Funestus Group, (An. aconitus, An. varuna), two species within the Dirus Complex (An. dirus, An. baimaii), and four species within the Maculatus Group (An. maculatus, An. sawadwongporni, An. pseudowillmori, and An. dravidicus). The trophic behavior of An. minimus, An. dirus, An. baimaii, An. maculatus, and An. sawadwongporni are described herein. The highest An. minimus densities were detected from February through April of both years. One specimen of An. minimus from Mae Sot was found positive for Plasmodium vivax.  相似文献   
104.
In Mytilus and Leucophaea the high-affinity binding site density is significantly lower in old animals than in young animals, whereas the low-affinity site density remains unchanged. In Mytilus the estimated met-enkephalin and met-enkephalin-Arg6-Phe7 levels are significantly higher in old than in young animals. In Leucophaea only the met-enkephalin level can be determined, and it is also higher in old animals. The decrease in the high-affinity binding site density and the corresponding increase in endogenous enkephalin levels suggest the existence of an opioid compensatory mechanism associated with the aging process. In Mytilus there is a demonstrated decrease with age in intraganglionic dopamine levels in response to applied opiates. In addition, the inhibition of dopamine-stimulated adenylate cyclase activity by opiates also decreases in older animals. In Leucophaea the sex difference in opioid binding densities diminishes with age.  相似文献   
105.
Plasma choline concentrations were measured in humans, rats, and rabbits within the first few hours of life, before any food was ingested. Neonatal animals and humans had markedly elevated plasma choline levels compared to adult animals or humans. Possible mechanisms responsible for this elevation are discussed and possible consequences for brain function, lung function, and growth are presented.  相似文献   
106.
107.
108.
109.
The mapping of genetic loci within organisms has been accelerated by the advent of Radiation Hybrid (RH) panels. These panels are available for humans and non-humans including mice, baboon, rat, and canine. This article contains a general protocol for the use of the Genebridge 4 whole genome RH panel to map a human locus. This protocol may also be adjusted to suit the other RH panels currently available.  相似文献   
110.
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