全文获取类型
收费全文 | 118篇 |
免费 | 22篇 |
国内免费 | 1篇 |
出版年
2019年 | 1篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2015年 | 4篇 |
2014年 | 1篇 |
2013年 | 4篇 |
2012年 | 3篇 |
2011年 | 4篇 |
2010年 | 6篇 |
2009年 | 5篇 |
2008年 | 2篇 |
2006年 | 4篇 |
2005年 | 6篇 |
2004年 | 1篇 |
2002年 | 1篇 |
1999年 | 3篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 4篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1972年 | 2篇 |
1959年 | 3篇 |
1958年 | 10篇 |
1957年 | 3篇 |
1956年 | 6篇 |
1955年 | 9篇 |
1954年 | 3篇 |
1953年 | 1篇 |
1952年 | 2篇 |
1951年 | 3篇 |
1950年 | 5篇 |
1949年 | 1篇 |
排序方式: 共有141条查询结果,搜索用时 31 毫秒
21.
CAROLYN M. OATES J. F. BISSENDEN R. N. MAINI L. N. PAYNE D. C. DUMONDE 《Nature: New biology》1972,239(92):137-139
AMONG the soluble products generated during activation of rodent or human lymphocytes1, lymphocyte-stimulating (‘mitogenic’) factors are detected by their ability to accelerate DNA metabolism of freshly cultured allogeneic or syngeneic lymphocytes2–8. If such lymphocyte activation products function as mediators of cellular immunity1,9–11, their activities will be generated independently of the antibody-forming system. In the chicken, antigen-stimulation of sensitized lymphocytes in vitro involves both thymus (T-) and bursa-(B-)-dependent cells12–14. If antigen-induced lymphocyte transformations are generally mediated by lymphocyte mitogenic factors, both T-cells and B-cells should produce lymphocyte mitogenic factors when stimulated by specific antigen. We have therefore determined whether antigen-stimulated chicken lymphocytes generate a lymphocyte mitogenic factor and whether this response is affected by neonatal thymectomy or bursectomy. 相似文献
22.
Retrotransposon BARE-1 and Its Role in Genome Evolution in the Genus Hordeum. 总被引:11,自引:0,他引:11
下载免费PDF全文
![点击此处可从《The Plant cell》网站下载免费的PDF全文](/ch/ext_images/free.gif)
CM Vicient A Suoniemi K Anamthawat-Jnsson J Tanskanen A Beharav E Nevo AH Schulman 《The Plant cell》1999,11(9):1769-1784
23.
24.
Physiological functions of beneficial elements 总被引:3,自引:0,他引:3
25.
Gordon W Slysz Charles AH Baker Benjamin M Bozsa Anthony Dang Andrew J Percy Melissa Bennett David C Schriemer 《BMC bioinformatics》2009,10(1):162
Background
Hydrogen/deuterium exchange mass spectrometry (H/DX-MS) experiments implemented to characterize protein interaction and protein folding generate large quantities of data. Organizing, processing and visualizing data requires an automated solution, particularly when accommodating new tandem mass spectrometry modes for H/DX measurement. We sought to develop software that offers flexibility in defining workflows so as to support exploratory treatments of H/DX-MS data, with a particular focus on the analysis of very large protein systems and the mining of tandem mass spectrometry data. 相似文献26.
27.
The liver is a target for toxic chemicals such as cadmium (Cd). When the liver is damaged, hepatic stellate cells (HSC) are activated and transformed into myofibroblast-like cells, which are responsible for liver fibrosis. Curcuma longa has been reported to exert a hepato-protective effect under various pathological conditions. We investigated the effects of C. longa administration on HSC activation in response to Cd induced hepatotoxicity. Forty adult male albino rats were divided into: group 1 (control), group 2 (Cd treated), group 3 (C. longa treated) and group 4 (Cd and C. longa treated). After 6 weeks, liver specimens were prepared for light and electron microscopy examination of histological changes and immunohistochemical localization of alpha smooth muscle actin (αSMA) as a specific marker for activated HSC. Activated HSC with a positive αSMA immune reaction were not detected in groups 1 and 3. Large numbers of activated HSC with αSMA immune reactions were observed in group 2 in addition to Cd induced hepatotoxic changes including excess collagen deposition in thickened portal triads, interlobular septa with hepatic lobulation, inflammatory cell infiltration, a significant increase in Kupffer cells and degenerated hepatocytes. In group 4, we observed a significant decrease in HSC that expressed αSMA with amelioration of the hepatotoxic changes. C. longa administration decreased HSC activation and ameliorated hepatotoxic changes caused by Cd in adult rats. 相似文献
28.
An experimental design and procedures for testing putative controls against naturally-occurring take-all in the field 总被引:1,自引:0,他引:1
D. HORNBY G. L. BATEMAN R. W. PAYNE M. E. BROWN D. R. HENDEN 《The Annals of applied biology》1989,115(2):195-208
In experiments during 1983–86 take-all was more severe and eyespot and sharp eyespot less frequent in 2nd-4th crops of winter wheat at Woburn (Beds.) than at Rothamsted (Herts.). Third crops had most take-all and yielded least grain. Against this background, small plots, 37 cm × 31 cm, in which all plants were sampled, were tried as a means of increasing experimental precision. They were arranged in fours in incomplete blocks and blocks with complementary treatments (putative controls of take-all) were paired. Thirty of these block-pairs were distributed throughout each experimental site in each year to provide one replicate of the design for each of three sampling times: April, June and August. Unattributed variation in disease and plant growth for plots within blocks was compared to that in other strata (block-pairs and blocks within block-pairs) of the experiment. The variability amongst block-pairs scattered throughout the site was nearly always greater than that for blocks within block-pairs (98% of take-all assessments, 71% of soil infectivity estimates, 94% of eyespot and sharp eyespot assessments and 86% of all plant measurements). The variability of blocks within block-pairs exceeded that of plots much less frequently (56% and 69% of take-all assessments, 33% and 25% of soil infectivity measurements, 63% and 56% of eyespot and sharp eyespot assessments and 50% and 63% of plant measurements; Rothamsted and Woburn, respectively). Small plots were judged mostly on this last comparison, where a variance ratio in excess of 1 indicated that the small plots had decreased variability and increased precision. Variance ratios for different assessments of take-all indicates that small plots: i) most consistently decreased disease variability during the years of maximum disease, ii) were slightly less effective at Rothamsted than at Woburn, and iii) were usually less effective in fourth crops than in previous crops. Soil infectivity was most uniform after crops with most disease and blocks were rarely more variable than plots. hxcept when disease was severe, soil infectivity in August tended to be positively associated with the yield of the crop just harvested. These findings reveal changes in the scale of disease patterns, both during the crop sequence and within individual crops, and suggest more than one scale of pattern in take-all-infested fields. This is discussed in relation to field experimentation and take-all decline. 相似文献
29.
Phytoremediation of selenium using transgenic plants 总被引:1,自引:0,他引:1
30.
D. RYAN GEORGIANNA † NATALIE D. FEDOROVA JAMES L. BURROUGHS REA L. DOLEZAL JIN WOO BOK SIGAL HOROWITZ-BROWN CHARLES P. WOLOSHUK JIUJIANG YU NANCY P. KELLER GARY A. PAYNE 《Molecular Plant Pathology》2010,11(2):213-226
Species of Aspergillus produce a diverse array of secondary metabolites, and recent genomic analysis has predicted that these species have the capacity to synthesize many more compounds. It has been possible to infer the presence of 55 gene clusters associated with secondary metabolism in Aspergillus flavus ; however, only three metabolic pathways—aflatoxin, cyclopiazonic acid (CPA) and aflatrem—have been assigned to these clusters. To gain an insight into the regulation of and to infer the ecological significance of the 55 secondary metabolite gene clusters predicted in A. flavus, we examined their expression over 28 diverse conditions. Variables included culture medium and temperature, fungal development, colonization of developing maize seeds and misexpression of laeA , a global regulator of secondary metabolism. Hierarchical clustering analysis of expression profiles allowed us to categorize the gene clusters into four distinct clades. Gene clusters for the production of aflatoxins, CPA and seven other unknown compound(s) were identified as belonging to one clade. To further explore the relationships found by gene expression analysis, aflatoxin and CPA production were quantified under five different cell culture environments known to be conducive or nonconducive for aflatoxin biosynthesis and during the colonization of developing maize seeds. Results from these studies showed that secondary metabolism gene clusters have distinctive gene expression profiles. Aflatoxin and CPA were found to have unique regulation, but are sufficiently similar that they would be expected to co-occur in substrates colonized with A. flavus . 相似文献