全文获取类型
收费全文 | 3259篇 |
免费 | 211篇 |
国内免费 | 3篇 |
出版年
2023年 | 18篇 |
2022年 | 35篇 |
2021年 | 99篇 |
2020年 | 42篇 |
2019年 | 78篇 |
2018年 | 58篇 |
2017年 | 62篇 |
2016年 | 91篇 |
2015年 | 144篇 |
2014年 | 158篇 |
2013年 | 242篇 |
2012年 | 284篇 |
2011年 | 233篇 |
2010年 | 154篇 |
2009年 | 156篇 |
2008年 | 175篇 |
2007年 | 220篇 |
2006年 | 170篇 |
2005年 | 168篇 |
2004年 | 135篇 |
2003年 | 120篇 |
2002年 | 101篇 |
2001年 | 35篇 |
2000年 | 32篇 |
1999年 | 20篇 |
1998年 | 25篇 |
1997年 | 17篇 |
1996年 | 23篇 |
1995年 | 15篇 |
1994年 | 18篇 |
1993年 | 9篇 |
1992年 | 21篇 |
1991年 | 21篇 |
1990年 | 10篇 |
1989年 | 15篇 |
1988年 | 8篇 |
1987年 | 14篇 |
1986年 | 11篇 |
1985年 | 8篇 |
1984年 | 12篇 |
1981年 | 14篇 |
1980年 | 13篇 |
1979年 | 18篇 |
1978年 | 8篇 |
1976年 | 7篇 |
1974年 | 6篇 |
1973年 | 6篇 |
1970年 | 7篇 |
1962年 | 7篇 |
1961年 | 9篇 |
排序方式: 共有3473条查询结果,搜索用时 15 毫秒
1.
Background
Spidroins are a unique family of large, structural proteins that make up the bulk of spider silk fibers. Due to the highly variable nature of their repetitive sequences, spidroin evolutionary relationships have principally been determined from their non-repetitive carboxy (C)-terminal domains, though they offer limited character data. The few known spidroin amino (N)-terminal domains have been difficult to obtain, but potentially contain critical phylogenetic information for reconstructing the diversification of spider silks. Here we used silk gland expression data (ESTs) from highly divergent species to evaluate the functional significance and phylogenetic utility of spidroin N-terminal domains. 相似文献2.
3.
Victoria Levterova Stefan Panaiotov Nadia Brankova Kristin Tankova 《Molecular biotechnology》2010,45(1):34-38
Identification of genetic markers involved in stress response to physical factors or chemical substances in organisms is a
challenging task. Typing of upregulated gene expression due to selective antibacterial pressure is a promising approach in
the search of molecular mechanisms responsible for development of resistance. cDNA-Fluorescent Amplified Fragment Length Polymorphism
(cDNA-FAFLP) strategy was developed and applied in the search of antimycotic drug resistance marker(s) in medically important
fungi as an alternative method to microarray analysis. We compared differential gene expression of two sensitive Candida albicans reference strains (ATCC 10231 and ATCC 60133) and two of their paired resistant to fluconazole and itraconazole mutants.
Resistant mutants Candida albicans
FLC-R, resistant to fluconazole (MIC > 128 μg/ml) and Candida albicans ICZ-R, resistant to itraconazole (MIC > 4 μg/ml) were obtained in subcultures with gradual increase of the antifungal in the culture
medium. cDNA-AFLP profile in both itraconazole resistant mutants showed specific spectrophotometric peaks with 5–6-fold RNA
overexpression product of 500 bp length compared to the sensitive strains. Fluconazole mutants do not reveal RNA level changes
under tested by us typing conditions. These results indicate that the cDNA-FAFLP strategy is a relatively rapid, simple, and
reliable method for simultaneous typing of both constitutive and induced differences in expression of host genes providing
insight into the biological processes involved in response to drugs in bacteria and fungi. Moreover, this methodology could
be tested for typing of the genome response of any organism to physical or chemical stress factors. 相似文献
4.
The red-striped soft scale insect Pulvinaria tenuivalvata (Newstead) (Hemiptera: Coccidae) started to infest sugarcane plants (Saccharum officinarum L.) in different districts in Egypt during the last decade. The percentage of infestation was recorded in El-Wakf area, Qena Governorate (Naghhamadi mill zone) Upper Egypt in some fields. There are three levels of infestation, low, intermediate and high. From these fields, samples were selected for physical and chemical studies. The results obtained show that the stalks of infested plants decreased in weight, the sugar content (glucose and sucrose) drastically reduced and as the percentage of infestation increased the percentage of glucose and sucrose content significantly decreased. The primary and secondary humidity and the cellulose content also increased in the healthy plants compared to the infested ones. All the physical character of the infested plants was significantly affected in comparison with the healthy ones. 相似文献
5.
6.
7.
8.
Synopsis A sensitive method is presented for measurement of changes in the permeability of mitchondria in cultured cells. Rat heart endothelioid cells were used to determine the penetration rate of nitroblue tetrazolium (NitroBT) or other reactants into mitochondriain situ. Nitroblue formazan, produced as a consequence of succinate dehydrogenase activity in the mitochondria, was eluted and measured with a spectrophotometer. Prior injury of cells with hypo-osmolar solutions increased the rate of formazan production. Several methods are described or suggested for the statistical analysis of the data. 相似文献
9.
10.