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   2504篇
  免费   232篇
  国内免费   2篇
  2023年   24篇
  2022年   36篇
  2021年   96篇
  2020年   43篇
  2019年   49篇
  2018年   78篇
  2017年   66篇
  2016年   76篇
  2015年   107篇
  2014年   122篇
  2013年   181篇
  2012年   199篇
  2011年   143篇
  2010年   102篇
  2009年   78篇
  2008年   102篇
  2007年   80篇
  2006年   98篇
  2005年   83篇
  2004年   61篇
  2003年   68篇
  2002年   59篇
  2001年   46篇
  2000年   29篇
  1999年   37篇
  1998年   18篇
  1997年   21篇
  1996年   19篇
  1995年   13篇
  1994年   15篇
  1993年   21篇
  1992年   42篇
  1991年   35篇
  1990年   37篇
  1989年   36篇
  1988年   25篇
  1987年   28篇
  1986年   38篇
  1985年   32篇
  1984年   32篇
  1983年   19篇
  1982年   20篇
  1981年   20篇
  1980年   15篇
  1979年   25篇
  1978年   17篇
  1977年   20篇
  1976年   20篇
  1975年   24篇
  1974年   24篇
排序方式: 共有2738条查询结果,搜索用时 15 毫秒
101.
102.
103.
Studies were conducted to determine the effect of iodine infusion on the luteal function of goats, as evident by blood progesterone concentration, and on plasma PGF2a levels. Ten cycling mixed breed goats were synchronized for estrus by PGF2a (5 mg) and given a single intrauterine iodine infusion on day 5 and on day 15 of the estrous cycle. Iodine infusion on day 5 (group II) resulted in shorter estrous length (8.2 days) and a 7-fold increase in plasma PGF2a concentration as compared to control animals (group I) given distilled water infusion. Similar infusion on day 15 (group III), on the other hand, failed to alter the estrous cycle length but induced a moderate increase in PGF2a concentration which lasted only for a brief period. The progesterone levels declined concomitantly as PGF2a levels rose after iodine infusion in group II animals but failed to decline until after 24 hours in group III animals. The studies indicate that the endometrium reacts to the chemical stimuli and releases PGF2a which, in turn, alters the luteal function.  相似文献   
104.
Pathogenesis of diabetes mellitus involves scores of different factors, out of which Glucagon like factor-1 (GLP-1) plays a foremost role. GLP-1 is a pepti  相似文献   
105.
106.
In Vitro Cellular & Developmental Biology - Plant - An efficient in vitro propagation and synthetic seed production protocol was established for the conservation of Decalepis salicifolia (Bedd....  相似文献   
107.
Abstract

Myceliophthora thermophila encodes for large number of carbohydrate-active enzymes (CAZymes) involved in lignocellulosic biomass degradation. The mould was grown on rice straw in solid state fermentation at pH 5.0 and 45?°C that produced high levels of cellulolytic and xylanolytic enzymes i.e. 2218.12, 515.23, 478.23, 13.34?U/g DMR for xylanase, CMCase, FPase and β-glucosidase, respectively. The secretome analysis of M. thermophila BJAMDU5 by mass spectroscopy, described 124 different proteins with majority of CAZymes consisting of glycosyl hydrolases (GH), lytic polysaccharide mono-oxygenases (LPMO), carbohydrate esterases (CE) and polysaccharide lyases (PL). Furthermore, the enzyme cocktail of the mould was evaluated for hydrolysis of steam treated rice straw that produced 184.59?mg/g substrate reducing sugars after 24?h, which was used for production of bioethanol by using fast fermenting yeast Saccharomyces cerevisiae resulting in high production of bioethanol.  相似文献   
108.
Certain species of the marine diatom genus Pseudo‐nitzschia are responsible for the production of the domoic acid (DA), a neurotoxin that can bioaccumulate in the food chain and cause amnesic shellfish poisoning (ASP) in animals and humans. This study extends our knowledge by reporting on the first observation of the potentially toxic species Pseudo‐nitzschia simulans from this region. One clonal strain of P. simulans was isolated from the East Australian Current and characterized using light and transmission electron microscopy, and phylogenetic analyses based on regions of the internal transcribed spacer (ITS) and the D1–D3 region of the large subunit (LSU) of the nuclear‐encoded ribosomal deoxyribonucleic acid (rDNA), as well as examined for DA production as measured by liquid chromatography–mass spectrometry. Although this strain was non‐toxic under the defined growth conditions, the results unambiguously confirmed that this isolate is the potentially toxic species P. simulans – the first report of this species from the Southern Hemisphere.  相似文献   
109.
Plant Molecular Biology - Cross-talk between light and ABA signaling is mediated by physical interaction between HY5 and ABI5 Arabidopsis. Plants undergo numerous transitions during their...  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