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   585篇
  免费   7篇
  592篇
  2015年   4篇
  2014年   6篇
  2013年   13篇
  2012年   11篇
  2011年   24篇
  2010年   37篇
  2009年   26篇
  2008年   21篇
  2007年   32篇
  2006年   12篇
  2005年   20篇
  2004年   4篇
  2003年   4篇
  2001年   4篇
  2000年   6篇
  1998年   14篇
  1997年   12篇
  1996年   15篇
  1995年   8篇
  1994年   14篇
  1993年   15篇
  1992年   13篇
  1991年   15篇
  1990年   10篇
  1989年   15篇
  1988年   8篇
  1986年   6篇
  1985年   6篇
  1984年   8篇
  1983年   7篇
  1982年   8篇
  1981年   10篇
  1980年   7篇
  1979年   15篇
  1978年   8篇
  1977年   9篇
  1976年   10篇
  1975年   14篇
  1974年   6篇
  1973年   7篇
  1972年   22篇
  1971年   14篇
  1970年   5篇
  1969年   4篇
  1967年   4篇
  1959年   4篇
  1958年   4篇
  1957年   4篇
  1952年   3篇
  1948年   3篇
排序方式: 共有592条查询结果,搜索用时 15 毫秒
51.
Seven monoclonal antibodies specific for mammalian β-tubulin demonstrate the microtubule cytoskeleton of Toxoplasma gondii and Leishmania donovani by indirect immunofluorescence microscopy. Immunoblots of T. gondii and L. donovani proteins separated by SDS polyacrylamide gel electrophoresis confirm the specificity of the monoclonal antibodies for tubulin. Differential staining of flagellar and subpellicular microtubule populations was not seen in L. donovani with these antibodies. All seven antibodies also detected the subpellicular microtubules of T. gondii, but the polar ring and conoid of this organism was not visualized by any of them. This technique provides a rapid and specific way to assess microtubular organization in whole organisms.  相似文献   
52.
Industrial microbiology of solar salt production   总被引:3,自引:0,他引:3  
Solar salterns can be modeled as giant outdoor chemostats, much like a series of dams on a slow-moving river. Microorganisms and their products play an essential, but sometimes uncharacterized, role in salt production in these ponds, from seawater salinity up through NaCl saturation. They may physically affect the evaporation process and their by-products may chemically modify or bind with dissolved ions. Many solar salt facilities engage microbiologists to establish monitoring programs for analyses of nutrients, standing crop and associated biological variables in the ponds. Other solar salt companies engage microbiologists only when there are “crises” in the ponds that interfere with salt production. Journal of Industrial Microbiology & Biotechnology (2002) 28, 42–47 DOI: 10.1038/sj/jim/7000173 Received 20 May 2001/ Accepted in revised form 13 June 2001  相似文献   
53.
The radiated tortoise (Geochelone radiata) is an endangered endemic species from Madagascar that inhabits the semiarid spiny forest of the southern part of the island. Habitat destruction and illegal harvesting greatly threaten this species, as attested by the significant reduction of its distribution area in the past 30 years. In order to undertake appropriate conservation actions, it is essential to acquire a better knowledge of its genetic structure. For this study, 145 blood samples were collected from three populations of radiated tortoises in southwestern Madagascar. Eight microsatellite loci were found to be polymorphic, and allelic diversity and observed heterozygosity were high for all markers.  相似文献   
54.
55.
SYNOPSIS. DNA synthesis of Toxoplasma gondii differs from that of other obligate intracellular parasites in that the parasite can synthesize DNA independently of the host cell and can incorporate preformed pyrimidines as well as pyrimidine precursors. However, pyrimidine precursors such as orotic acid are preferentially utilized over preformed pyrimidines such as thymidine. There is little apparent utilization of purine precursors.  相似文献   
56.
57.
Female Ascetics in Hinduism. Lynn Teskey Denton. Albany: State University of New York Press, 2004. 218 pp.
The Graceful Guru: Hindu Female Gurus in India and the United States. Karen Pechilis, ed. Oxford: Oxford University Press, 2004. 260 pp.
Offering Flowers, Feeding Skulls: Popular Goddess Worship in West Bengal. June McDaniel. Oxford and New York: Oxford University Press, 2004. 356 pp.  相似文献   
58.
We describe primers and polymerase chain reaction (PCR) conditions to amplify 18 tetranucleotide microsatellite DNA loci in eastern bluebirds (Sialia sialis). The primers were tested using individuals from two study sites in Georgia and South Carolina. Among individuals from the Georgia population (n = 23), the primer pairs developed in this study yielded an average of 6.6 alleles per locus (range 2–12), an average observed heterozygosity of 0.56 (range 0.24–0.96) and an average polymorphic information content of 0.65 (range 0.3–0.86). Among individuals from the South Carolina population (n = 19), the primer pairs yielded an average of 5.8 alleles per locus (range 2–9), an average observed heterozygosity of 0.56 (range 0.05–0.86) and an average polymorphic information content of 0.63 (range 0.29–0.83).  相似文献   
59.
Melanophores, xanthophores, and iridophores are fundamentallydistinct chromatophores in their appearance, composition, andfunction. All migrate from their neural crest site of originto populate the integument. Their respective pigments, melanins,ptendines, and purines are found in organelles designated respectivelyas melanosomes, pterinosomes and reflecting platelets. Theseorganelles are all derived from an endoplasmic reticular vesicle.This is in keeping with a hypothesis about the common originof pigment cells from a stem cell containing a primordial organellewith the potential of becoming any of the circumscribed pigmentaryorganelles. It is believed that chromatoblasts may not be specificallydetermined until they reach a final destination where they willdifferentiate in accordance with a pattern already specifiedin the integument. In leopard frogs, it appears that the initialinduction of pattern in the skin is general, but later it becomeshighly specific.  相似文献   
60.
There is a need for safe medications that can effectively support recovery by treating symptoms of protracted abstinence that may precipitate relapse in alcoholics, e.g. craving and disturbances in sleep and mood. This proof-of-concept study reports on the effectiveness of gabapentin 1200 mg for attenuating these symptoms in a non-treatment-seeking sample of cue-reactive, alcohol-dependent individuals. Subjects were 33 paid volunteers with current Diagnostic and Statistical Manual of Mental Disorders-IV alcohol dependence and a strength of craving rating 1 SD or greater for alcohol than water cues. Subjects were randomly assigned to gabapentin or placebo for 1 week and then participated in a within-subjects trial where each was exposed to standardized sets of pleasant, neutral and unpleasant visual stimuli followed by alcohol or water cues. Gabapentin was associated with significantly greater reductions than placebo on several measures of subjective craving for alcohol as well as for affectively evoked craving. Gabapentin was also associated with significant improvement on several measures of sleep quality. Side effects were minimal, and gabapentin effects were not found to resemble any major classes of abused drugs. Results suggest that gabapentin may be effective for treating the protracted abstinence phase in alcohol dependence and that a randomized clinical trial would be an appropriate next step. The study also suggests the value of cue-reactivity studies as proof-of-concept screens for potential antirelapse drugs.  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