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   454篇
  免费   16篇
林业   1篇
基础科学   1篇
  16篇
综合类   114篇
农作物   5篇
水产渔业   8篇
畜牧兽医   315篇
园艺   4篇
植物保护   6篇
  2017年   6篇
  2014年   9篇
  2013年   12篇
  2012年   9篇
  2011年   16篇
  2010年   11篇
  2009年   10篇
  2008年   17篇
  2007年   26篇
  2006年   11篇
  2005年   16篇
  2004年   19篇
  2003年   16篇
  2002年   10篇
  2001年   15篇
  2000年   21篇
  1999年   11篇
  1998年   19篇
  1997年   6篇
  1996年   8篇
  1995年   8篇
  1994年   3篇
  1993年   5篇
  1992年   9篇
  1991年   11篇
  1990年   11篇
  1989年   14篇
  1988年   14篇
  1987年   13篇
  1986年   9篇
  1985年   4篇
  1984年   4篇
  1983年   4篇
  1982年   3篇
  1979年   8篇
  1976年   5篇
  1974年   4篇
  1973年   4篇
  1972年   8篇
  1971年   4篇
  1960年   2篇
  1959年   2篇
  1955年   2篇
  1948年   2篇
  1947年   4篇
  1940年   2篇
  1939年   2篇
  1937年   3篇
  1935年   2篇
  1884年   3篇
排序方式: 共有470条查询结果,搜索用时 31 毫秒
371.
372.
miRNAs are small non‐coding regulatory RNAs that play key roles in diverse biological processes. In this study, we used the Solexa sequencing technique to profile miRNAs in breeder cock testes to illustrate their functions. A total of 663 co‐expressed miRNAs and 3,180 co‐expressed piRNAs were detected in three libraries. Based on Mir‐X? miRNA qRT‐PCR, three miRNAs representing low, medium and high expression levels according to the sequencing results were selected randomly to validate the miRNAs' expression profiles. Results suggested that the miRNA expression profiles data could represent actual miRNA expression levels. Moreover, target genes prediction of the co‐expressed miRNAs and further Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were performed, which revealed that some candidate miRNAs were involved in the regulation of the spermatogenesis process, spermatozoa function and testicular metabolism. In conclusion, we provided a useful resource for further elucidation of the miRNAs' regulatory role in spermatogenesis, contributing to a preliminary database for functional and molecular mechanistic studies in testicular metabolism, spermatogenesis and other testes functions.  相似文献   
373.
374.
Glucocorticoid deficiency was diagnosed as the cause of severe postanesthetic hypoglycemia in 2 dogs. Prior signs of systemic illness were not described in either dog; however, preoperative hematologic findings were consistent with glucocorticoid deficiency. Fasting hypoglycemia is a possible complication of chronic adrenal insufficiency primarily because of impaired gluconeogenesis.  相似文献   
375.
Bluetongue virus (BTV) exists around the world in a broad band covering much of the Americas, Africa, southern Asia and northern Australia. Historically, it also occasionally occurred in the southern fringes of Europe. It is considered to be one of the most important diseases of domestic livestock. Recently BTV has extended its range northwards into areas of Europe never before affected and has persisted in many of these locations causing the greatest epizootic of bluetongue (BT), the disease caused by BTV, on record. Indeed, the most recent outbreaks of BT in Europe are further north than this virus has ever previously occurred anywhere in the world. The reasons for this dramatic change in BT epidemiology are complex but are linked to recent extensions in the distribution of its major vector, Culicoides imicola, to the involvement of novel Culicoides vector(s) and to on-going climate-change. This paper investigates these recent outbreaks in the European theatre, up to the beginning of 2006, highlights prospects for the future and sets the scene for the following papers in this special issue.  相似文献   
376.
Endogenous estrogens are known to affect the activity of monoamine neurotransmitters in vertebrate animals, but the effects of exogenous estrogens on neurotransmitters are relatively poorly understood. We exposed sexually mature male fighting fish Betta splendens to environmentally relevant and pharmacological doses of three phytoestrogens that are potential endocrine disruptors in wild fish populations: genistein, equol, and β-sitosterol. We also exposed fish to two doses of the endogenous estrogen 17β-estradiol, which we selected as a positive control because phytoestrogens are putative estrogen mimics. Our results were variable, but the effects were generally modest. Genistein increased dopamine levels in the forebrains of B. splendens at both environmentally relevant and pharmacological doses. The environmentally relevant dose of equol increased dopamine levels in B. splendens forebrains, and the pharmacological dose decreased norepinephrine (forebrain), dopamine (hindbrain), and serotonin (forebrain) levels. The environmentally relevant dose of β-sitosterol decreased norepinephrine and dopamine in the forebrain and hindbrain, respectively. Our results suggest that sources of environmental phytoestrogens, such as runoff or effluent from agricultural fields, wood pulp mills, and sewage treatment plants, have the potential to modulate neurotransmitter activity in free-living fishes in a way that could interfere with normal behavioral processes.  相似文献   
377.
378.
379.
To assess some characteristics in chickpea (Cicer arietinum) global germplasm, a genetically diverse subset from the USDA global chickpea core collection was assayed. The greenhouse experiment evaluated 39 global accessions and commercial cultivar UC-5, inoculated with Mesorhizobium ciceri. The design was carried out at greenhouse of Washington State University in complete block design with 6 replications in 2011. Flower number, biomass and ratio shoot to root (shoot/root) were determined. The results showed that cultivar had significant effect on flower number and biomass. The maximum flower number and biomass obtained ACNO 360456 from Iran and ACNO 339223 from Turkey respectively. The biomass had a positive, significant correlation with number of flower. ACNO = Accession number  相似文献   
380.
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