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   605篇
  免费   67篇
  国内免费   32篇
  2022年   6篇
  2021年   10篇
  2020年   9篇
  2019年   7篇
  2018年   13篇
  2017年   10篇
  2016年   14篇
  2015年   15篇
  2014年   21篇
  2013年   33篇
  2012年   46篇
  2011年   45篇
  2010年   24篇
  2009年   22篇
  2008年   37篇
  2007年   18篇
  2006年   36篇
  2005年   16篇
  2004年   16篇
  2003年   20篇
  2002年   11篇
  2001年   12篇
  2000年   8篇
  1999年   9篇
  1998年   15篇
  1997年   12篇
  1996年   6篇
  1995年   9篇
  1994年   7篇
  1993年   7篇
  1992年   12篇
  1990年   9篇
  1989年   6篇
  1988年   9篇
  1987年   8篇
  1984年   4篇
  1983年   7篇
  1981年   11篇
  1980年   6篇
  1979年   8篇
  1978年   6篇
  1977年   9篇
  1976年   5篇
  1975年   8篇
  1974年   8篇
  1973年   4篇
  1972年   7篇
  1971年   4篇
  1970年   5篇
  1949年   5篇
排序方式: 共有704条查询结果,搜索用时 15 毫秒
81.
构建博尔纳病病毒pEGFP-p24基因重组表达质粒。通过PCR方法扩增获得博尔纳病痛毒p24基因的完整序列,将此片段定向克隆到pEGFP-N1载体多克隆位点区,筛选重组阳性菌株,提取重组质粒,利用PCR方法和核酸序列测定验证重组质粒构建的正确性。PCR及核酸序列测定证明博尔纳病病毒pEGFP-p24基因重组表达质粒构建成功。构建的重组质粒将为研究博尔纳病病毒p24基因在真核细胞中的功能和作用提供实验依据。  相似文献   
82.
83.
The horn fly, Haematobia irritans (L.) (Diptera: Muscidae), is a cosmopolitan livestock pest that has caused a great negative impact on the animal production sector throughout the world. Here, we describe 10 polymorphic microsatellite loci isolated from H. irritans. The number of alleles found ranged from two to eight per locus and the expected heterozygosity from 0.1421 to 0.7702. These loci are potentially useful for the fine-scale genetic characterization of horn fly populations and provide fundamental information for pest management and planning of control programs.  相似文献   
84.
Our study focused on colony dynamics of the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), in relation to the standard practice of planting rye grass (i.e., plowing) in the fall in Louisiana. Microsatellite molecular markers were used to determine genotypes of individuals from red imported fire ant colonies. These markers allowed us to monitor treatment effect by detecting changes in number and location of colonies in response to disking of pasture plots. Previous research on mound disturbance as a form of cultural control in pastures has produced mixed results. We found that the majority of colonies persisted on plots after plowing. Mound density and mound area, 5 mo after plowing, were not significantly different among treatments. In contrast, April measurements of mound volume were significantly smaller on plowed plots compared with control plots. A closer look at the rebuilding of mounds on plowed plots, during the 5 mo, showed that mound heights stayed below pretreatment measurements and they were significantly smaller than those of undisturbed mounds. Whether plowing has potential for use as a cultural control technique in reducing the impact of red imported fire ant mounds on agricultural practices in pastures remains to be seen. Conceivably, the best application of this technique will be in combination with other control measures in an integrated pest management approach to control red imported fire ants in pastures.  相似文献   
85.
INTRODUCTIONEstrogen has been known to exert extensive effects via estrogen receptor (ER) on diverse physio-logical and develoPmental functions of the brain[1,2]. It has been observed that the distribution ofthe classical ER subtype-a (ERa) and the recentlycharacterized novel ER subtype--fi (ERg), and theirexpression patterns (ERcr/ERfi) vary greatly amongvarious brain regions[1, 3]. These evidences suggestthat each ER subtype may play a different role inestrogen's effects on the br…  相似文献   
86.
87.
88.
89.
90.
Infectious and inflammatory diseases in the intestine remain a serious threat for patients world-wide. Reprogramming of the intestinal epithelium towards a protective effector state is important to manage inflammation and immunity and can be therapeutically targeted. The role of epigenetic regulatory enzymes within these processes is not yet defined. Here, we use a mouse model that has an intestinal-epithelial specific deletion of the histone demethylase Lsd1 (cKO mice), which maintains the epithelium in a fixed reparative state. Challenge of cKO mice with bacteria-induced colitis or a helminth infection model both resulted in increased pathogenesis. Mechanistically, we discovered that LSD1 is important for goblet cell maturation and goblet-cell effector molecules such as RELMß. We propose that this may be in part mediated by directly controlling genes that facilitate cytoskeletal organization, which is important in goblet cell biology. This study therefore identifies intestinal-epithelial epigenetic regulation by LSD1 as a critical element in host protection from infection.  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