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   182篇
  免费   4篇
  国内免费   2篇
系统科学   4篇
现状及发展   109篇
研究方法   15篇
综合类   60篇
  2018年   5篇
  2017年   2篇
  2016年   4篇
  2015年   2篇
  2014年   2篇
  2012年   7篇
  2011年   13篇
  2010年   2篇
  2008年   7篇
  2007年   4篇
  2006年   10篇
  2005年   7篇
  2004年   3篇
  2003年   2篇
  2002年   2篇
  2001年   2篇
  2000年   4篇
  1999年   2篇
  1997年   1篇
  1996年   2篇
  1994年   1篇
  1993年   2篇
  1992年   3篇
  1991年   1篇
  1990年   2篇
  1987年   2篇
  1985年   8篇
  1984年   5篇
  1982年   4篇
  1981年   1篇
  1980年   4篇
  1979年   5篇
  1978年   10篇
  1977年   6篇
  1976年   6篇
  1975年   12篇
  1974年   3篇
  1973年   5篇
  1972年   2篇
  1971年   2篇
  1970年   1篇
  1969年   1篇
  1968年   4篇
  1967年   3篇
  1966年   5篇
  1965年   1篇
  1963年   1篇
  1962年   1篇
  1961年   2篇
  1957年   1篇
排序方式: 共有188条查询结果,搜索用时 31 毫秒
61.
62.
63.
Choanoflagellates are the closest known relatives of metazoans. To discover potential molecular mechanisms underlying the evolution of metazoan multicellularity, we sequenced and analysed the genome of the unicellular choanoflagellate Monosiga brevicollis. The genome contains approximately 9,200 intron-rich genes, including a number that encode cell adhesion and signalling protein domains that are otherwise restricted to metazoans. Here we show that the physical linkages among protein domains often differ between M. brevicollis and metazoans, suggesting that abundant domain shuffling followed the separation of the choanoflagellate and metazoan lineages. The completion of the M. brevicollis genome allows us to reconstruct with increasing resolution the genomic changes that accompanied the origin of metazoans.  相似文献   
64.
More than 1,000 susceptibility loci have been identified through genome-wide association studies (GWAS) of common variants; however, the specific genes and full allelic spectrum of causal variants underlying these findings have not yet been defined. Here we used pooled next-generation sequencing to study 56 genes from regions associated with Crohn's disease in 350 cases and 350 controls. Through follow-up genotyping of 70 rare and low-frequency protein-altering variants in nine independent case-control series (16,054 Crohn's disease cases, 12,153 ulcerative colitis cases and 17,575 healthy controls), we identified four additional independent risk factors in NOD2, two additional protective variants in IL23R, a highly significant association with a protective splice variant in CARD9 (P < 1 × 10(-16), odds ratio ≈ 0.29) and additional associations with coding variants in IL18RAP, CUL2, C1orf106, PTPN22 and MUC19. We extend the results of successful GWAS by identifying new, rare and probably functional variants that could aid functional experiments and predictive models.  相似文献   
65.
This paper obtains sufficient optimality conditions for a nonlinear nondifferentiable multiobjective semi-infinite programming problem involving generalized(C,α,ρ,d)-convex functions.The authors formulate Mond-Weir-type dual model for the nonlinear nondifferentiable multiobjective semiinfinite programming problem and establish weak,strong and strict converse duality theorems relating the primal and the dual problems.  相似文献   
66.
67.
Protein misfolding under stressful environmental conditions cause several cellular problems owing to the disturbed cellular protein homeostasis, which may further lead to neurological disorders like Parkinson’s disease (PD), Alzheimer’s disease (AD), Amyloid lateral sclerosis and Huntington disease (HD). The presence of cellular defense mechanisms like molecular chaperones and proteasomal degradation systems prevent protein misfolding and aggregation. Molecular chaperones plays primary role in preventing protein misfolding by mediating proper native folding, unfolding and refolding of the polypeptides along with vast number of cellular functions. In past few years, the understanding of molecular chaperone mechanisms has been expanded enormously although implementation to prevent protein aggregation diseases is still deficient. We in this review evaluated major classes of molecular chaperones and their mechanisms relevant for preventing protein aggregation, specific case of α-synuclein aggregation. We also evaluate the molecular chaperone function as a novel therapeutic approach and the chaperone inhibitors or activators as small molecular drug targets.  相似文献   
68.
Summary The structure of koenigicine as 8,9-dimethoxy-3,3,5-trimethyl-3, 11-dihydropyrano-[3,2-a] carbazole (1) has been confirmed by synthesis.  相似文献   
69.
Quality is the hallmark of a competitive product. It is necessary to use inspection stations to check product quality and process performance. In this paper, we are concerned with the problem of location of inspection stations in a manufacturing system. A simulated annealing approach is developed to determine the location of inspection centers resulting in a minimum expected total cost in a multistage serial production system. The total cost includes inspection, processing, and scrapping costs at each stage of the production process. A penalty cost is also included in it to account for a defective item which is not detected by the inspection scheme. A set of test examples is solved using a simulated annealing algorithm.  相似文献   
70.
Electrophoretic pattern of esterases from larvae ofTribolium castaneum fed on a diet which included hormetic concentrations of azadirachtin (viz. 0.001, 0.01 and 0.1 ppm) for 10 d were studied. The results showed a dose-dependent variation in the multiple molecular forms of the esterases. The variations, however, were not limited to the synthesis of new isoforms or the deletion of existing ones; there was also variation in their relative abundance.  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