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   162篇
  免费   20篇
  2022年   6篇
  2021年   6篇
  2020年   5篇
  2018年   5篇
  2017年   3篇
  2016年   4篇
  2015年   8篇
  2014年   5篇
  2013年   15篇
  2012年   7篇
  2011年   6篇
  2010年   13篇
  2009年   6篇
  2008年   4篇
  2007年   3篇
  2004年   5篇
  2003年   2篇
  2001年   3篇
  1999年   4篇
  1998年   4篇
  1997年   5篇
  1996年   4篇
  1995年   3篇
  1993年   2篇
  1992年   2篇
  1991年   3篇
  1990年   2篇
  1988年   2篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1983年   1篇
  1982年   2篇
  1980年   1篇
  1978年   1篇
  1977年   1篇
  1975年   4篇
  1974年   2篇
  1973年   1篇
  1970年   1篇
  1968年   2篇
  1958年   5篇
  1957年   1篇
  1956年   2篇
  1955年   2篇
  1954年   2篇
  1953年   4篇
  1952年   4篇
  1951年   2篇
  1949年   1篇
排序方式: 共有182条查询结果,搜索用时 328 毫秒
161.
ABSTRACT. We demonstrated here the presence of proteins antigenically related to human erythroid spectrin in the parasitic protozoan Toxoplasma gondii . A high molecular weight doublet (M, 245-240,000), present in equimolar ratio, and low molecular weight polypeptides (M, 75,000) were reacted with monoclonal and polyclonal anti-human erythroid spectrin antibodies on electroblotted nitrocellulose sheets. Indirect immunofluorescence assay clearly showed that these proteins were localized in the anterior pole of the organism. Immunogold staining further revealed specific labeling of conoid, rhoptries, micronemes, and dense granules of the apical complex. The presence of the M, 245–240,000 doublet and the M, 75,000 spectrin-like proteins in the anterior pole of T. gondii may probably be consistent with a structural stabilizer function in its organciles which are suspected to be involved in the process of host cell invasion.  相似文献   
162.
Abstract. The overall prevalence of Theileria species, mainly, if not exclusively, T.annulata, in 901 Hyalomma detritum detritum collected from cattle in the Doukkala region of Morocco over a period of 2 years was 21.5%. The quantity of infection (number of sporoblasts per infected tick) followed the negative binomial distribution with between one and 250 sporoblasts per infected tick. Infected ticks were found in eight of fourteen areas examined whilst T.annulata was present in all fourteen. There were significant differences in both the prevalence and the quantity of infection between ticks collected from different farms, and between nymphs collected in the autumn from these farms, and moulted in the laboratory, and adults collected in the following summer. The prevalence, but not the quantity, of infection was higher in female than in male ticks. No correlations were established between infection of engorged nymphs and the breed, sex and Theileria piroplasm parasitaemia of the host animal. However, calves infected a greater proportion of nymphs than adult cattle and the heavier the infestation of nymphs on an animal, up to a plateau, the higher the prevalence of infection in those nymphs. There were no differences in infection between ticks moulted at 24oC and 37oC, after the engorged nymphs had been stored at 18oC to simulate over-wintering.  相似文献   
163.
Totally 39% out of 8371 feed and their component samples were contaminated by aflatoxin B1. Mean contamination was 36μg/kg with maximum yield 10100 μg/kg. Contamination of samples by total count of organisms, mean contamination and maximum yield, respectively was: 1) bacteria 99%, 2.2×106, 2.4×108; 2) proteolytic bacteria 94%, 1.2×105, 3.0×106;3) moulds 98%, 1.3×105, 9.0×106; 4) yeasts 44 %, 3.3×104, 3.6×106. The samples were contaminated in 92 % byAspergillus spp, in 71% byAspergillus flavus, in 83% byPenicillium spp, and in 20% byFusarium spp with mean contamination 8.3×104, 1.1×103, 4.2×104, 5.0×103 , and maximum yield 6.8×106, 1.0×105, 5.0×106, 1.5×106, respectively. Totally 8.5% of strains were aflatoxinogenic and 4.4% of the strains were isolated from feed and 21 % of the strains from grain/nut.  相似文献   
164.
165.
Naproxen and cromolyn were investigated as new inhibitors of glycogen synthase kinase‐3β (GSK‐3β) in an attempt to explain their hypoglycemic properties. Study included simulated docking experiments, in vitro enzyme inhibition assay, and in vivo validations. Both drugs not only were optimally fitted within a GSK‐3β binding pocket via several attractive interactions with key amino acids but also exhibited potent in vitro enzymatic inhibitory activities of IC50 1.5 and 2.0 µM for naproxen and cromolyn, respectively. In vivo experiments illustrated that both drugs significantly reduced serum glucose and increased hepatic glycogen‐ and serum insulin levels in normal and type II diabetic Balb/c mice models. In obese animal model, both drugs exhibited significant reduction in mice weights, serum glucose, and resistin levels along with significant elevation in serum insulin, C‐peptide, and adiponectin values. It can be concluded that naproxen and cromolyn are novel GSK‐3β inhibitors and can help in management of diabetes and obesity. © 2013 Wiley Periodicals, Inc. J BiochemMol Toxicol 27:425–436, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/jbt.21503  相似文献   
166.
Throughout east–central United States, Lexington/Trenton limestones are largely Late Ordovician (Chatfieldian; mid-Caradoc), argillaceous, skeletal calcarenites, which are transgressive upward into Late Ordovician (late Chatfieldian–Edenian; mid-late Caradoc) shales and interbedded micrograined limestones. In central Kentucky, however, the same sequence is partially truncated by an unconformity and passes upward into a thicker, younger (Edenian; late Caradoc), regressive shoal complex of coarse calcarenites and calcirudites that is not generally typical of the Lexington/Trenton sequence elsewhere. The shoal complex is interpreted to have been a carbonate buildup and is partially bound by extant faults with basement precursors. Comparison of isopachous maps for pre- and postunconformity buildup units with basement structural lineaments suggests that the buildup is related to reactivation—and in one prominent case, inversion—of the basement structures. The coincidence of structural reactivation, inversion, and buildup development with other major regional, cratonic changes may reflect a reorganization of cratonic, far-field forces accompanying a nearly coeval reversal in the polarity of Taconic subduction.  相似文献   
167.
168.
169.
170.
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