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   69篇
  免费   4篇
  73篇
  2022年   1篇
  2021年   2篇
  2019年   1篇
  2018年   4篇
  2017年   1篇
  2015年   5篇
  2014年   3篇
  2013年   5篇
  2012年   7篇
  2011年   4篇
  2008年   2篇
  2007年   2篇
  2006年   3篇
  2005年   2篇
  2004年   3篇
  2003年   4篇
  2002年   2篇
  2001年   1篇
  2000年   1篇
  1999年   2篇
  1998年   1篇
  1997年   1篇
  1996年   3篇
  1990年   1篇
  1989年   2篇
  1982年   1篇
  1980年   1篇
  1979年   1篇
  1978年   1篇
  1976年   1篇
  1971年   1篇
  1952年   2篇
  1951年   1篇
  1950年   1篇
排序方式: 共有73条查询结果,搜索用时 15 毫秒
1.
Summary Twelve different chemical extraction procedures for extracting soil manganese were used. Soil test values determined for fourteen representative soil samples of Rajasthan State with manganese uptake by six crop species have shown that of the extractants used, 3N ammonium dihydrogen orthophosphate can be best used for estimating plant available soil manganese.  相似文献   
2.
Recombinant production of complex eukaryotic proteins for structural analyses typically requires a profound screening process to identify suitable constructs for the expression of ample amounts of properly folded protein. Furthermore, the evaluation of an optimal expression host has a major impact on protein yield and quality as well as on actual cost of the production process. Here we present a novel fast expression system for multiple hosts based on a single donor vector termed pFlp-Bac-to-Mam. The range of applications of pFlp-Bac-to-Mam comprises highly efficient transient transfection of HEK293-6E in serum-free suspension culture and subsequent large-scale production of challenging proteins expressing in mg per Liter level using either the baculoviral expression vector system or stable CHO production cell lines generated by Flp-mediated cassette exchange. The success of the multi-host expression vector to identify the optimal expression strategy for efficient production of high quality protein is demonstrated in a comparative expression study of three model proteins representing different protein classes: intracellular expression using a fluorescent protein, secretion of a single-chain-Fv-hIgG1Fc fusion construct and production of a large amount of highly homogeneous protein sample of the extracellular domain of a Toll-like receptor. The evaluation of the production efficiency shows that the pFlp-Bac-to-Mam system allows a fast and individual optimization of the expression strategy for each protein class.  相似文献   
3.
To evaluate clinical and molecular predictors of the risk of mortality in people with neurofibromatosis 2 (NF2), we analyzed the mortality experience of 368 patients from 261 families in the United Kingdom NF2 registry, using the Cox proportional-hazards model and the jackknife method. Age at diagnosis, intracranial meningiomas, and type of treatment center were informative predictors of the risk of mortality. In Cox models, the relative risk of mortality increased 1.13-fold per year decrease in age at diagnosis (95% confidence interval [CI] 1.08-1.18) and was 2.51-fold greater in people with meningiomas compared with those without meningiomas (95% CI 1.38-4.57). The relative risk of mortality in patients treated at specialty centers was 0.34 compared with those treated at nonspecialty centers (95% CI 0.12-0.98). In a separate model, the relative risk of mortality in people with constitutional NF2 missense mutations was very low compared with those with other types of mutations (nonsense or frameshift mutations, splice-site mutations, and large deletions), but the CI could not be well quantified because there was only one death among people with missense mutations. We conclude that age at diagnosis, the strongest single predictor of the risk of mortality, is a useful index for patient counseling and clinical management (as are intracranial meningiomas). To ensure optimal care, we recommend that people with NF2 be referred to specialty treatment centers.  相似文献   
4.
From the underground parts of Thalictrum orientale Boiss., a new phenolic compound 1 was isolated in addition to one known cyanoglycoside, lithospermoside (2). For the structure elucidation of all compounds, 1D- and 2D-NMR techniques (DEPT, COSY, HMBC, HSQC) and MS (HR-MALDI) were used. The structure of the new compound was established as 2-(4'-hydroxyphenyl)-nitroethane-4'-O-[beta-xylopyranosyl-(1 --> 6)-beta-glucopyranoside] (1).  相似文献   
5.
6.
Effects of carvacrol upon the liver of rats undergoing partial hepatectomy   总被引:1,自引:0,他引:1  
The present study aims to investigate the possible effects of carvacrol obtained from origanum oil upon the regenerative feature of the liver subsequent to partial hepatectomy in rats.Male Wistar Albino rats, weighing 230±30 g, were divided into three experiment groups. Group I (n=8) were used as sham operation group. Group II (n=8) were applied saline solution and hepatectomy. Carvacrol and hepatectomy (73 mg/kg) were applied to Group III (n=8). One dose of test material was injected 1 h before 68% partial hepatectomy. At the end of the experiments, blood and organs were removed. The liver regeneration rate of the rats was calculated measuring the weights of their liver before and after the hepatectomy. Hematoxylin and eosin, interleukin-6 (IL-6) and proliferating cell nuclear antigen (PCNA) treatments were applied to liver sections. Aspartate transaminase (AST), alanine transaminase (ALT), tumor necrosis factor-alpha (TNF-α) and IL-6 levels were determined in serum samples.The liver regeneration, mitotic index and PCNA index increased significantly in rats of Group III over the Group II at the 72nd hour after partial hepatectomy. Histological evaluations were also similar with these results of PCNA and mitotic indexes. In AST, ALT, TNF-α and IL-6 levels, there was no statistically significant difference.According to these results, it is concluded that carvacrol increases the liver regeneration rate.  相似文献   
7.

Background  

Very often genome-wide data analysis requires the interoperation of multiple databases and analytic tools. A large number of genome databases and bioinformatics applications are available through the web, but it is difficult to automate interoperation because: 1) the platforms on which the applications run are heterogeneous, 2) their web interface is not machine-friendly, 3) they use a non-standard format for data input and output, 4) they do not exploit standards to define application interface and message exchange, and 5) existing protocols for remote messaging are often not firewall-friendly. To overcome these issues, web services have emerged as a standard XML-based model for message exchange between heterogeneous applications. Web services engines have been developed to manage the configuration and execution of a web services workflow.  相似文献   
8.

Introduction  

The vast difference in the abundance of different proteins in biological samples limits the determination of the complete proteome of a cell type, requiring fractionation of proteins and peptides before MS analysis.  相似文献   
9.
10.
Since 2008, Drosophila suzukii, the spotted wing drosophila, has colonized most of the American and European continents, being able to adapt to very different climates. In Italy, this pest has been captured from northern Alpine to southern Mediterranean regions where it can infest a broad range of fruits, including wine grapes. Studies have shown that oviposition levels and developmental rates of D. suzukii on wine grapes are lower than on other berries, although recent observations indicate that grapes may become a suitable host plant in particular conditions. Here, we report, for the first time, the results of a series of no‐choice oviposition experiments using berries of five table grape varieties sampled in the provinces of Taranto and Bari (Apulia region, south‐eastern Italy) during 2013 from both organic and conventional farming systems. The sugar content (SC) and skin hardness of each sample were analysed to assess the influence of these physiological parameters on the susceptibility of table grapes to D. suzukii infestation. A negative correlation was found between the number of eggs laid and berry skin penetration force, whereas there was a positive one between the number of eggs and Brix values, as well as sampling date. In organic grapes, SC and skin hardness of two varieties (“Crimson” and “Scarlotta”) were measured, respectively, higher and lower than in conventional grapes, thus making them more susceptible to pest infestation. The study hence shows that in laboratory conditions D. suzukii is able to heavily infest and develop on table grapes and that susceptibility to its infestation significantly depends on both variety and farming system.  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