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   281篇
  免费   15篇
  2022年   6篇
  2021年   5篇
  2020年   2篇
  2019年   7篇
  2018年   5篇
  2017年   11篇
  2016年   14篇
  2015年   15篇
  2014年   21篇
  2013年   34篇
  2012年   23篇
  2011年   28篇
  2010年   12篇
  2009年   9篇
  2008年   12篇
  2007年   14篇
  2006年   10篇
  2005年   13篇
  2004年   3篇
  2003年   22篇
  2002年   8篇
  2001年   4篇
  2000年   2篇
  1999年   1篇
  1998年   1篇
  1997年   2篇
  1996年   1篇
  1994年   1篇
  1993年   1篇
  1992年   1篇
  1990年   2篇
  1989年   3篇
  1988年   2篇
  1985年   1篇
排序方式: 共有296条查询结果,搜索用时 15 毫秒
291.
The tissue distribution of activin receptor-like kinase 7 (Alk7) expression, the signaling ability of Alk7 variants, and Alk7 expression in response to β3-adrenergic receptor activation were examined. Expression levels of Alk7 varied greatly among tissues but were highest in white adipose tissue and brown adipose tissue. In addition to full-length Alk7 (Alk7-v1), Alk7-v3, an Alk7 variant, was expressed in adipose tissues, brain, and ovary. Nodal transmits signals via Alk7 in cooperation with its coreceptor, Cripto. Evaluation of the ability of Alk7 variants to confer Nodal signaling using luciferase-based reporter assays showed that Alk7-v3 does not transmit Nodal-Cripto-mediated signals. Expression of Alk7 was down-regulated in brown but not in white adipose tissue treated with CL316,243, a β3-adrenergic receptor agonist. These results suggest involvement of Alk7 in modulation of metabolism in the adipose tissues in response to β3-adrenergic receptor activation.  相似文献   
292.
To determine the wild host plants of four major spider mite species infesting fruit crops grown in the subtropical Asian region, we collected and identified mites from non-crop plants throughout the islands of Okinawa, southwestern Japan. Although the two mango pests, Oligonychus coffeae and O. biharensis, are polyphagous, they did not share any wild host species in the field, indicating that their source plants are completely separate in Okinawa. Several major wild hosts were determined for Eutetranychus africanus, a pest of papaya and citrus. Its host range partially overlapped with that of O. biharensis. The citrus red mite, Panonychus citri, was very rare on non-crop plants in Okinawa, suggesting that it maintains its population mainly on the citrus trees in the area. These results are of great significance when considering vegetation control as part of the integrated management of these pest mites. During our survey, two non-pest species, Panonychus caglei (new to Japan) and Oligonychus gotohi (new to Okinawa), were also found.  相似文献   
293.
We used quantitative nuclear magnetic resonance analyses to measure the contents of major constituents of Acorus rhizome materials used as herbal drugs. The inhibitory effects of crude n-hexane extracts and their individual constituents on in vitro acetylcholine esterase activity were evaluated. The crude extracts had unexpectedly weak inhibitory effects (46–64% inhibition at 1.0 mg/mL), despite the high content (46–64%) of β-asarone, which independently had a potent effect (IC50 2.9 µM [0.61 µg/mL]). Further investigation revealed participation of eudesmin A, a lignan constituent, in the suppression of the inhibitory effect of β-asarone.  相似文献   
294.
Ichthyological Research - Despite its potential use for population control, the winter ecology of nonnative fishes is still poorly understood due to the difficulty of conducting field surveys. In...  相似文献   
295.
A new riffle beetle species Optioservus gapyeongensis n. sp. is described from the adult and larval stages. Heterlimnius hasegawai (Nomura), previously misidentified in Korea as Optioservus (Cyclolimnius) kubotai Nomura or Optioservus variabilis Nomura, is redescribed. The adults and larvae of both species inhabit attached mosses on substrates of clean mountain streams, headwaters or springs. Photographs of dorsal adults and habitats and line drawings of diagnostic characters are provided.  相似文献   
296.
Microbial production of 1,5-diaminopentane (DAP) from renewable feedstock is a promising and sustainable approach for the production of polyamides. In this study, we constructed a β-glucosidase (BGL)-secreting Corynebacterium glutamicum and successfully used this strain to produce DAP from cellobiose and glucose. First, C. glutamicum was metabolically engineered to produce l -lysine (a direct precursor of DAP), followed by the coexpression of l -lysine decarboxylase and BGL derived from Escherichia coli and Thermobifida fusca YX (Tfu0937), respectively. This new engineered C. glutamicum strain produced 27 g/L of DAP from cellobiose in CGXII minimal medium using fed-batch cultivation. The yield of DAP was 0.43 g/g glucose (1 g of cellobiose corresponds to 1.1 g of glucose), which is the highest yield reported to date. These results demonstrate the feasibility of DAP production from cellobiose or cellooligosaccharides using an engineered C. glutamicum strain.  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