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   962篇
  免费   56篇
  国内免费   1篇
  2024年   1篇
  2023年   11篇
  2022年   35篇
  2021年   46篇
  2020年   57篇
  2019年   103篇
  2018年   66篇
  2017年   57篇
  2016年   52篇
  2015年   53篇
  2014年   49篇
  2013年   89篇
  2012年   79篇
  2011年   55篇
  2010年   44篇
  2009年   39篇
  2008年   40篇
  2007年   41篇
  2006年   22篇
  2005年   23篇
  2004年   27篇
  2003年   11篇
  2002年   13篇
  2000年   2篇
  1999年   1篇
  1998年   1篇
  1997年   1篇
  1996年   1篇
排序方式: 共有1019条查询结果,搜索用时 297 毫秒
991.
Allothrombium pulvinum Ewing is a common natural enemy of aphids and other arthropods in Iran. It is univoltine in Iran. The eggs hatch in spring, nymphs emerge in early summer and adults appear in autumn. Larvae are ectoparasites of aphids whereas deutonymphs and adults are free-living predators of aphids and spider mites. Adults hibernate in the soil and in cracks of tree trunks during winter. When spring comes, females lay eggs in the soil, on the soil surface and on weeds. Phytoseius plumifer (Phytoseiidae) was observed to be phoretic on deutonymphs of A. pulvinum on nettle trees (Celtis australis). In the laboratory, development from the egg to adult stage takes at least 107 days at 25±1°C. Soil is not essential for female oviposition. High humidity is the most important factor for oviposition and development in A. pulvinum.  相似文献   
992.
Taking account of heat shock factor A4A (HSFA4A) as a hydrogen peroxide sensor, anti-apoptosis agent, and crosslink component with critical signaling cascades, the current study was carried out to monitor possible changes in expression of this gene as well as some other important characteristics in wheat plants exposed to selenium nano-particle (nSe). Wheat seedlings were treated with nSe (0, 5, 10, and 50 mgl?1). In germinating stage, plant fresh weights were reduced in nSe-treated seedlings, among which the nSe of 50 provoked roots turned brown. The nSe triggered the increases in the expressions of HSFA4A, in the plate. In the pot condition, shoot fresh weights in nSe-supplemented seedlings were decreased by approximately 22%. The nSe of 5 and 10 mgl?1, respectively induced the expression of HSFA4A by 3.4- and 9.15-folds, contrasted with nSe50. Increasing times of sprays caused the dramatic reductions of the expression of HSFA4A in the nSe-supplemented groups. Moreover, the treatment of nSe stimulated expression of high molecular weight glutenin subunit 1Bx (Glu-1Bx) by fourfold, over the control. While the dramatic decrease in the expression of Glu-1Bx was recorded with increasing times of spray. Nitrate reductase activities were significantly improved by approximately 47% in nSe-fortified seedlings. Also, the foliar supplementation of nSe of 5 mgl?1 provoked the significant inductions in peroxidase activity by 8%, whereas two other nSe treatments declined it. It may be stated that the nSe may modify the expression of HSFA4A, thereby triggering specific signaling and altering metabolism.  相似文献   
993.
Bioprocess and Biosystems Engineering - In this study, NiO nanosheets have been manufactured using a co-precipitation approach that involved the usage of nickel nitrate (Ni (NO3)2.6H2O) as the raw...  相似文献   
994.
Plasmonics - In this paper, some biological sensors based on surface plasmon resonance are proposed at visible and near-infrared wavelengths and their performance is improved. The structure of...  相似文献   
995.
Molecular Biology Reports - Genome-wide association studies have revealed that some single nucleotide polymorphisms at 8q24, such as rs6983267, might be effective in susceptibility to various...  相似文献   
996.
Cytotoxicity of umbelliprenin has been found in various cancer cell lines such as, prostate, breast, CLL, and skin. Encapsulating chemotherapeutic agents with nanoliposomes have been resulted in improved cytotoxicity effects than their free forms. However, whether nanoliposomal form of umbelliprenin could have higher cytotoxic effect than free umbelliprenin is not clarified yet. After synthesizing umbelliprenin, different concentrations (3, 6, 12, 25, 50, 100, 200 μg/ml) applied on the mouse mammary carcinoma cell line (4T1) for 24, 48, and 72 h at 37°C. Afterwards, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was performed to analyze cytotoxicity. MTT assay results showed that IC50 of umbelliprenin in dimethyl sulfoxide (DMSO) (30.92, 30.64, and 62.23 for 24, 48, 72 h incubation, respectively) decreased (5.8, 5.0, 3.5 for 24, 48, 72 h incubation, respectively) when encapsulated with nanoliposomes. Nanoliposomal umbelliprenin cytotoxicity affected cell viability in concentration and time-dependent manner. Our study recommended nanoliposomal umbelliprenin as the most effective chemotherapeutic agent against the mouse mammary carcinoma cell line viability. Future in vivo studies and clinical trials are needed.  相似文献   
997.
998.
999.
1000.
Premature termination codons (PTC) cause over 10% of genetic disease cases. Some aminoglycosides that bind to the ribosome decoding center can induce PTC readthrough and restore low levels of full-length functional proteins. However, concomitant inhibition of protein synthesis limits the extent of PTC readthrough that can be achieved by aminoglycosides like G418. Using a cell-based screen, we identified a small molecule, the phenylpyrazoleanilide Y-320, that potently enhances TP53, DMD, and COL17A1 PTC readthrough by G418. Unexpectedly, Y-320 increased cellular protein levels and protein synthesis, measured by SYPRO Ruby protein staining and puromycin labeling, as well as ribosome biogenesis measured using antibodies to rRNA and ribosomal protein S6. Y-320 did not increase the rate of translation elongation and it exerted its effects independently of mTOR signaling. At the single cell level, exposure to Y-320 and G418 increased ribosome content and protein synthesis which correlated strongly with PTC readthrough. As a single agent, Y-320 did not affect translation fidelity measured using a luciferase reporter gene but it enhanced misincorporation by G418. RNA-seq data showed that Y-320 up-regulated the expression of CXC chemokines CXCL10, CXCL8, CXCL2, CXCL11, CXCL3, CXCL1, and CXCL16. Several of these chemokines exert their cellular effects through the receptor CXCR2 and the CXCR2 antagonist SB225002 reduced cellular protein levels and PTC readthrough in cells exposed to Y-320 and G418. These data show that the self-limiting nature of PTC readthrough by G418 can be compensated by Y-320, a potent enhancer of PTC readthrough that increases ribosome biogenesis and protein synthesis. They also support a model whereby increased PTC readthrough is enabled by increased protein synthesis mediated by an autocrine chemokine signaling pathway. The findings also raise the possibility that inflammatory processes affect cellular propensity to readthrough agents and that immunomodulatory drugs like Y-320 might find application in PTC readthrough therapy.

A cell-based screen identifies a small molecule, Y-320, that potently enhances readthrough of premature termination codons by the aminoglycoside G418. Y-320 increases cellular protein levels and protein synthesis, and appears to act via an autocrine chemokine signaling pathway.  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