全文获取类型
收费全文 | 152篇 |
免费 | 5篇 |
专业分类
157篇 |
出版年
2023年 | 1篇 |
2021年 | 2篇 |
2020年 | 3篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 4篇 |
2014年 | 5篇 |
2013年 | 5篇 |
2012年 | 7篇 |
2011年 | 8篇 |
2010年 | 4篇 |
2009年 | 7篇 |
2008年 | 6篇 |
2007年 | 7篇 |
2006年 | 6篇 |
2005年 | 7篇 |
2004年 | 4篇 |
2003年 | 7篇 |
2002年 | 3篇 |
2001年 | 5篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1998年 | 9篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 6篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1986年 | 2篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有157条查询结果,搜索用时 0 毫秒
61.
GMDD: a database of GMO detection methods 总被引:1,自引:0,他引:1
Wei Dong Litao Yang Kailin Shen Banghyun Kim Gijs A Kleter Hans JP Marvin Rong Guo Wanqi Liang Dabing Zhang 《BMC bioinformatics》2008,9(1):260
Background
Since more than one hundred events of genetically modified organisms (GMOs) have been developed and approved for commercialization in global area, the GMO analysis methods are essential for the enforcement of GMO labelling regulations. Protein and nucleic acid-based detection techniques have been developed and utilized for GMOs identification and quantification. However, the information for harmonization and standardization of GMO analysis methods at global level is needed. 相似文献62.
Bakker BM Overkamp KM van Maris AJ Kötter P Luttik MA van Dijken JP Pronk JT 《FEMS microbiology reviews》2001,25(1):15-37
In Saccharomyces cerevisiae, reduction of NAD(+) to NADH occurs in dissimilatory as well as in assimilatory reactions. This review discusses mechanisms for reoxidation of NADH in this yeast, with special emphasis on the metabolic compartmentation that occurs as a consequence of the impermeability of the mitochondrial inner membrane for NADH and NAD(+). At least five mechanisms of NADH reoxidation exist in S. cerevisiae. These are: (1) alcoholic fermentation; (2) glycerol production; (3) respiration of cytosolic NADH via external mitochondrial NADH dehydrogenases; (4) respiration of cytosolic NADH via the glycerol-3-phosphate shuttle; and (5) oxidation of intramitochondrial NADH via a mitochondrial 'internal' NADH dehydrogenase. Furthermore, in vivo evidence indicates that NADH redox equivalents can be shuttled across the mitochondrial inner membrane by an ethanol-acetaldehyde shuttle. Several other redox-shuttle mechanisms might occur in S. cerevisiae, including a malate-oxaloacetate shuttle, a malate-aspartate shuttle and a malate-pyruvate shuttle. Although key enzymes and transporters for these shuttles are present, there is as yet no consistent evidence for their in vivo activity. Activity of several other shuttles, including the malate-citrate and fatty acid shuttles, can be ruled out based on the absence of key enzymes or transporters. Quantitative physiological analysis of defined mutants has been important in identifying several parallel pathways for reoxidation of cytosolic and intramitochondrial NADH. The major challenge that lies ahead is to elucidate the physiological function of parallel pathways for NADH oxidation in wild-type cells, both under steady-state and transient-state conditions. This requires the development of techniques for accurate measurement of intracellular metabolite concentrations in separate metabolic compartments. 相似文献
63.
Three experiments were carried out to examine the consequences of concurrent infections with Ascaridia galli and Escherichia coli in chickens raised for table egg production. Characteristic pathological lesions including airsacculitis, peritonitis and/or polyserositis were seen in all groups infected with E. coli. Furthermore, a trend for increased mortality rates was observed in groups infected with both organisms which, however, could not be confirmed statistically. The mean worm burden was significantly lower in combined infection groups compared to groups infected only with A. galli. It was also shown that combined infections of E. coli and A. galli had an added significant negative impact on weight gain. 相似文献
64.
65.
Castagnone-Sereno P; Semblat JP; Leroy F; Abad P 《Molecular biology and evolution》1998,15(9):1115-1122
A highly abundant satellite DNA comprising 20% of the Meloidogyne fallax
(Nematoda, Tylenchida) genome was cloned and sequenced. The satellite
monomer is 173 bp long and has a high A + T content of 72.3%, with frequent
runs of A's and T's. The sequence variability of the monomers is 2.7%,
mainly due to random distribution of single-point mutations. A search for
evidence of internal repeated subunits in the monomer sequence revealed a
6-bp motif (AAATTT) for which five degenerated repeats, differing by just a
single base pair, could be identified. Pairwise comparison of the M. fallax
satellite with those from the sympatric species Meloidogyne chitwoodi and
Meloidogyne hapla revealed a high sequence similarity (68.39%) with one
satellite DNA subfamily in M. chitwoodi, which indicated an unexpected
close relationship between them. Given the high copy number and the extreme
sequence homogeneity among monomeric units, it may be assumed that the
satellite DNA of M. fallax could have evolved through some recent and
extensive amplification burst in the nematode genome. In this case, its
relatively short life would not yet have allowed the accumulation of random
mutations in independent amplified repeats. Considering the morphological
resemblance between the two species and their ability to produce
interspecific fertile hybrids under controlled conditions, these results
indicate that M. fallax may share a common ancestor with M. chitwoodi, from
which it could have diverged recently. All these data suggest that M.
fallax could be the result of a recent speciation process and show that
Meloidogyne satellite DNAs may be of interest to resolve phylogenetic
relationships among closely related species from this genus.
相似文献
66.
K. Mazzocco P. Scaruffi C. Gambini F. Negri G. P. Tonini 《Apoptosis : an international journal on programmed cell death》1996,1(1):63-68
We studied apoptosis in 36 neuroblastomas by DNA ladder assay. Expression of bcl2- and mRNA isoforms and protein were detected by RT-PCR and by immunohistochemistry, respectively. Internucleosomal DNA fragmentation was found in 20/36 (56%) tumor tissues collected both at onset and relapse of disease. Bcl-2 and mRNAs and protein were found in almost all examined tumors irrespective of DNA ladder, thus showing lack of correlation with the clinical stage. BCL-2 protein was observed to be expressed at various levels in undifferentiated and in more differentiated neuroblasts, while the stroma and the fibrovascular tissue were negative. Our results show that apoptosis is present in neuroblastoma at all stages and that bcl-2 gene is widely expressed in tumor tissue. In our series of neuroblastomas, bcl-2 expression is not correlated with unfavorable prognosis. 相似文献
67.
68.
Tim?Lu Christine?M?Costello Peter?JP?Croucher Robert?H?sler Günther?Deuschl Stefan?SchreiberEmail author 《BMC bioinformatics》2005,6(1):37
Background
Normalization is the process of removing non-biological sources of variation between array experiments. Recent investigations of data in gene expression databases for varying organisms and tissues have shown that the majority of expressed genes exhibit a power-law distribution with an exponent close to -1 (i.e. obey Zipf's law). Based on the observation that our single channel and two channel microarray data sets also followed a power-law distribution, we were motivated to develop a normalization method based on this law, and examine how it compares with existing published techniques. A computationally simple and intuitively appealing technique based on this observation is presented. 相似文献69.
70.