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   426篇
  免费   38篇
  2024年   1篇
  2023年   3篇
  2022年   13篇
  2021年   18篇
  2020年   13篇
  2019年   8篇
  2018年   13篇
  2017年   12篇
  2016年   21篇
  2015年   27篇
  2014年   27篇
  2013年   29篇
  2012年   33篇
  2011年   32篇
  2010年   19篇
  2009年   22篇
  2008年   17篇
  2007年   22篇
  2006年   22篇
  2005年   10篇
  2004年   8篇
  2003年   9篇
  2002年   9篇
  2001年   8篇
  2000年   14篇
  1999年   10篇
  1998年   4篇
  1997年   2篇
  1996年   1篇
  1994年   1篇
  1993年   1篇
  1992年   1篇
  1991年   3篇
  1990年   7篇
  1989年   3篇
  1988年   2篇
  1987年   2篇
  1986年   2篇
  1985年   3篇
  1984年   1篇
  1977年   1篇
  1975年   1篇
  1974年   1篇
  1973年   3篇
  1972年   1篇
  1971年   1篇
  1969年   1篇
  1966年   1篇
  1962年   1篇
排序方式: 共有464条查询结果,搜索用时 31 毫秒
1.
A preliminary survey of the few units of the small-scale glass bangle industry in Firozabad, Agra District, Uttar Pradesh, indicated that the workers were exposed to severe degrees of heat stress during various operations in the manufacturing processes. A more detailed study in eight glass bangle units was therefore undertaken to make quantitative estimates of heat stress on exposed workers in the summer season. The thermal data collected confirmed that the heat stress on the workers was severe but measurement of certain physiological indicators revealed relatively low levels of strain amongst the exposed workers. The findings could be attributable to high degrees of acclimatization, but further observations in the field supplemented by studies on simulated exposures of volunteers in a climatic chamber seem to be warranted.  相似文献   
2.
Human fibrinogen exposed to protease III from Crotalus atrox venom is cleaved near the NH2 terminus of the B beta chain yielding a species of Mr 325,000 (Fg325) with impaired thrombin clottability. The derivative was compared with intact fibrinogen in a number of ways to determine whether the functional defect resulted from a conformational change or from the loss of a polymerization site. NH2-terminal amino acid sequencing of isolated A alpha, B beta, and gamma chains showed that Fg325 contained intact A alpha and gamma chains, but differed from fibrinogen by the absence of the first 42 residues of the B beta chain. Fibrinopeptide A was present and was cleaved at the same rate in both fibrinogen and Fg325. The rate and extent of A alpha and gamma cross-linking by factor XIIIa was also indistinguishable. In contrast, the thrombin-catalyzed coagulation of Fg325 was 46% less in extent and 180-fold slower than observed for intact fibrinogen. A conformational comparison of Fg325 and fibrinogen was made using immunochemical and spectroscopic approaches. Antisera specific for different regions of the fibrinogen molecule were used to characterize the epitopes in Fg325. The only significant differences were found in the NH2-terminal region of the B beta chain, probed with antiserum to B beta 1-118. The conformational similarity of Fg325 and fibrinogen was confirmed by the identity of both near and far UV CD spectra of the two proteins. Structural, functional, and immunochemical results imply that cleavage of 42 NH2-terminal residues from the B beta chain is not accompanied by a measurable conformational change. The residues of this B beta chain segment, which are evidently located on the surface of the molecule, in conjunction with the NH2-terminal part of the A alpha chain appear to play an important role in the expression of a fibrin polymerization site.  相似文献   
3.
DNA haplotype analyses of patients with hyperphenylalaninemia.   总被引:1,自引:1,他引:0       下载免费PDF全文
Linkage analysis of phenylketonurics has shown a strong association between the DNA haplotype at the phenylalanine hydroxylase (PAH) locus and phenylketonuria (PKU). Similarly, a genetic linkage between less severe forms of hyperphenylalaninemia (HPA) and the PAH locus has been suggested. In the present study we analyzed this linkage in more detail. Haplotypes at the PAH locus were determined for 19 individuals with moderately elevated plasma phenylalanine and normal urinary neopterin/biopterin ratios. Fourteen of these individuals had plasma phenylalanine levels of 4-10 mg/dl (mild HPA), and the other five had plasma phenylalanine levels of 10-19 mg/dl (atypical PKU). Thirteen of the 15 HPA families consisted of an affected child and at least one other sibling. Elevated plasma phenylalanine was seen to genetically segregate with specific PAH alleles in each family. Summation of the LOD scores for both categories of moderate plasma phenylalanine elevation gave a maximum value of 3.556 at theta = 0. At theta = 0 this gives a probability of linkage between the PAH locus and the locus for moderate phenylalanine elevations that is approximately 3,600:1. None of the alleles segregating with either mild HPA or atypical PKU were of haplotype 2 or 3, and 13/20 were of types 1 or 4. This is in agreement with the most deleterious mutations being on haplotypes 2 and 3 and with the less severe mutations being on haplotypes 1 and 4. chi 2 Analyses indicated no statistically significant correlation between HPA and a particular haplotype or restriction-enzyme site.  相似文献   
4.
5.
6.
7.
Mughees  Mohd  Chugh  Himanshu  Wajid  Saima 《Protoplasma》2020,257(2):345-352
Protoplasma - Vesicular trafficking between endoplasmic reticulum and Golgi plays a major role in the growth and proliferation of breast cancer cells. Various proteins regulate this ER-Golgi...  相似文献   
8.
Molecular Biology Reports - Introns experience lesser selection pressure, thus are liable for higher polymorphism. Intron Length Polymorphic (ILP) markers designed from exon-flanking introns...  相似文献   
9.
Sharma  Himanshu  Kumar  Pankaj  Singh  Abhishek  Aggarwal  Kanika  Roy  Joy  Sharma  Vikas  Rawat  Sandeep 《Molecular biology reports》2020,47(4):2447-2457
Molecular Biology Reports - The genus Rhododendron, known for large impressive flowers is widely distributed throughout the world. Rhododendrons have limited genetic information, despite of...  相似文献   
10.
The molecular pathogenesis of avian influenza infection varies greatly with individual bird species and virus strain. The molecular pathogenesis of the highly pathogenic avian influenza virus (HPAIV) or the low pathogenic avian influenza virus (LPAIV) infection in avian species remains poorly understood. Thus, global immune response of chickens infected with HPAI H5N1 (A/duck/India/02CA10/2011) and LPAI H9N2 (A/duck/India/249800/2010) viruses was studied using microarray to identify crucial host genetic components responsive to these infection. HPAI H5N1 virus induced excessive expression of type I IFNs (IFNA and IFNG), cytokines (IL1B, IL18, IL22, IL13, and IL12B), chemokines (CCL4, CCL19, CCL10, and CX3CL1) and IFN stimulated genes (OASL, MX1, RSAD2, IFITM5, IFIT5, GBP 1, and EIF2AK) in lung tissues. This dysregulation of host innate immune genes may be the critical determinant of the severity and the outcome of the influenza infection in chickens. In contrast, the expression levels of most of these genes was not induced in the lungs of LPAI H9N2 virus infected chickens. This study indicated the relationship between host immune genes and their roles in pathogenesis of HPAIV infection in chickens.  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