全文获取类型
收费全文 | 774篇 |
免费 | 49篇 |
国内免费 | 1篇 |
专业分类
824篇 |
出版年
2024年 | 2篇 |
2023年 | 9篇 |
2022年 | 27篇 |
2021年 | 41篇 |
2020年 | 18篇 |
2019年 | 22篇 |
2018年 | 41篇 |
2017年 | 40篇 |
2016年 | 39篇 |
2015年 | 44篇 |
2014年 | 56篇 |
2013年 | 79篇 |
2012年 | 65篇 |
2011年 | 90篇 |
2010年 | 42篇 |
2009年 | 34篇 |
2008年 | 36篇 |
2007年 | 35篇 |
2006年 | 31篇 |
2005年 | 23篇 |
2004年 | 25篇 |
2003年 | 9篇 |
2002年 | 9篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1996年 | 2篇 |
排序方式: 共有824条查询结果,搜索用时 15 毫秒
151.
Himalayan soils undergo dramatic temporal changes in their microclimatic properties. The soil habitats in the high altitude
cold habitats of Himalayas are little explored with respect to bacterial diversity and metabolic potentials of the bacterial
species. Soil habitat in Western Himalayas is dominated by the genera of Pseudomonas, Arthrobacter, Bacillus, and Flavobacterium. Strains were found to be diverse in their metabolic potentials to utilize different carbon sources by growing them on media
containing 114 different sole carbon sources. Bacillus sp. STL9 was supported by the lowest number (12.3%) of the carbon sources while growth was observed in 73.7% of the carbon
sources tested for the Pseudomonas sp. SPS2. Carbohydrates appeared to be preferred carbon sources for these Himalayan isolates followed by amino acids and
proteins. These microbes also produced various extra-cellular hydrolytic enzymes having biotechnological potentials, lipase
being the one secreted by most strains (85.7%) followed by β-galactosidase (42.8%). Antibiotic resistance profiling for 85
different antibiotics has also been described. 相似文献
152.
153.
154.
155.
The genus Psorotheciopsis Rehm recorded by Cunningham from Calcutta in 1879 has been rediscovered for India after a gap of 135 years. The taxonomic characters of Psorotheciopsis patellarioides (Rehm) Rolf Santesson are provided to facilitate the identification of the species. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
156.
REP- and ERIC-PCR genotyping were used to assess genetic heterogeneity among 81 strains of Yersinia enterocolitica biotype 1A isolated from India, Germany, France and the USA. Although both gave comparable results, ERIC fingerprints discriminated the strains better. The rep- (REP and ERIC) PCR genotyping showed that strains having different serotypes produced identical rep-profiles indicating their limited genetic diversity. The concatenated dendrogram of REP- and ERIC-PCR fingerprints clustered the biotype 1A strains into two major groups. In each group, majority of the Indian, European and American strains exhibited similarities ranging from 85% to >95%. Similarity of rep-PCR fingerprints amongst strains isolated from widely separated geographical regions revealed existence of a limited number of clonal groups of Y. enterocolitica biotype 1A. The present study failed to reveal unequivocal relationships between rep-PCR genotypes and the source of isolation. However, the clinical serotype O:6,30-6,31 strains formed a tight cluster and the aquatic O:6,30-6,31 strains formed a yet another tight cluster. 相似文献
157.
S Ramachandran Y Sridhar S Kishore Gnana Sam M Saravanan J Thomas Leonard N Anbalagan S K Sridhar 《Phytomedicine》2004,11(2-3):165-168
In the present study, the aphrodisiac activity of Butea frondonsa Koen. ex Roxb (Papillionaceae) bark extract was investigated. The extract (400 mg/kg body wt./day) was administered orally by gavage for 28 days. Mount latency (ML), intromission latency (IL), ejaculation latency (EL), mounting frequency (MF), intromission frequency (IF), ejaculation frequency (EF) and post-ejaculatory interval (PEI) were the parameters observed before and during the sexual behavior study at day 0, 7, 10, 14, 21, and 28. The extract reduced significantly ML, IL, EL and PEI (p < 0.05). The extract also increased significantly MF, IF and EF (p < 0.05). These effects were observed in sexually active and inactive male rats. 相似文献
158.
Jordan Woodrick Suhani Gupta Pooja Khatkar Sanchita Sarangi Ganga Narasimhan Akriti Trehan Sanjay Adhikari Rabindra Roy 《Nucleic acids research》2014,42(14):9033-9046
Repair of oxidative stress- and inflammation-induced DNA lesions by the base excision repair (BER) pathway prevents mutation, a form of genomic instability which is often observed in cancer as ‘mutation hotspots’. This suggests that some sequences have inherent mutability, possibly due to sequence-related differences in repair. This study has explored intrinsic mutability as a consequence of sequence-specific repair of lipid peroxidation-induced DNA adduct, 1, N6-ethenoadenine (εA). For the first time, we observed significant delay in repair of ϵA at mutation hotspots in the tumor suppressor gene p53 compared to non-hotspots in live human hepatocytes and endothelial cells using an in-cell real time PCR-based method. In-cell and in vitro mechanism studies revealed that this delay in repair was due to inefficient turnover of N-methylpurine-DNA glycosylase (MPG), which initiates BER of εA. We determined that the product dissociation rate of MPG at the hotspot codons was ≈5–12-fold lower than the non-hotspots, suggesting a previously unknown mechanism for slower repair at mutation hotspots and implicating sequence-related variability of DNA repair efficiency to be responsible for mutation hotspot signatures. 相似文献
159.
Saravanan Thavamanikumar Luke J. McManus Peter K. Ades Gerd Bossinger Desmond J. Stackpole Richard Kerr Sara Hadjigol Jules S. Freeman René E. Vaillancourt Peng Zhu Josquin F. G. Tibbits 《Tree Genetics & Genomes》2014,10(6):1661-1678
The moderate to high levels of nucleotide diversity and low linkage disequilibrium found in many forest tree species make them ideal candidates for association mapping. Here, we report candidate gene-based association mapping results for complex wood quality and growth traits in Eucalyptus globulus Labill. ssp. globulus, the most widely grown eucalypt in temperate regions of the world. Ninety-eight single nucleotide polymorphisms (SNPs) from 20 wood quality candidate genes were assayed in a discovery population consisting of 385 trees sourced from a provenance-progeny trial. Twenty-five selected SNPs with significant associations (P?0.05) in the discovery population were assayed for validation in 296 trees sourced from an independent second-generation breeding trial. To account for background genetic structure, mixed models were used in the association analyses. Two associations identified in the discovery population were independently supported in the validation testing. However, combining the discovery and validation results in a combined analysis, we discovered nine stable marker-trait associations for seven traits. These associations link underlying complex wood and growth phenotypes to earlier putative selection signatures opening new avenues to accelerate the dissection of these traits. 相似文献
160.