全文获取类型
收费全文 | 285篇 |
免费 | 25篇 |
出版年
2023年 | 1篇 |
2022年 | 3篇 |
2021年 | 8篇 |
2020年 | 2篇 |
2019年 | 6篇 |
2018年 | 2篇 |
2017年 | 7篇 |
2016年 | 7篇 |
2015年 | 9篇 |
2014年 | 8篇 |
2013年 | 20篇 |
2012年 | 12篇 |
2011年 | 21篇 |
2010年 | 13篇 |
2009年 | 11篇 |
2008年 | 10篇 |
2007年 | 13篇 |
2006年 | 16篇 |
2005年 | 18篇 |
2004年 | 12篇 |
2003年 | 12篇 |
2002年 | 17篇 |
2001年 | 11篇 |
2000年 | 6篇 |
1999年 | 10篇 |
1998年 | 2篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1975年 | 3篇 |
1974年 | 1篇 |
1973年 | 5篇 |
1972年 | 2篇 |
排序方式: 共有310条查询结果,搜索用时 453 毫秒
31.
32.
Leão SC Bernardelli A Cataldi A Zumarraga M Robledo J Realpe T Mejía GI da Silva Telles MA Chimara E Velazco M Fernandez J Rodrigues PA Guerrero MI León CI Porras TB Rastogi N Goh KS Suffys P da Silva Rocha A dos Santos Netto D Ritacco V López B Barrera L Palomino JC Martin A Portaels F 《Journal of microbiological methods》2005,61(2):193-199
The identification of mycobacterial species in clinical isolates is essential for making patient care decisions. Polymerase chain reaction (PCR) restriction enzyme analysis (PRA) is a simple and rapid identification method, based on amplification of 441 bp of the hsp65 gene and restriction with BstEII and HaeIII. As a contribution to the validation of PRA, a multicenter study was performed in eight laboratories located in Argentina, Brazil, Colombia, Chile, and Guadeloupe. Each laboratory received 18 coded isolates from the collection of the Institute of Tropical Medicine (Antwerp, Belgium), representing duplicates of nine laboratory strains: Mycobacterium terrae CIPT 140320001, Mycobacterium scrofulaceum CIPT 140220031, Mycobacterium flavescens ATCC 14474, Mycobacterium triviale ATCC 23292, Mycobacterium nonchromogenicum ATCC 19530, Mycobacterium chitae ATCC 19627, Mycobacterium abscessus ATCC 19977, Mycobacterium kansasii ATCC 12478, and Mycobacterium peregrinum ATCC 14467. A detailed protocol including amplification, enzymatic digestion, and gel preparation was provided to each laboratory. Two laboratories identified correctly all 18 (100%) isolates, one identified correctly 17 (94.5%), two identified 14 (77.7%), one identified 11 (61%), and two identified 8 (44.4%) isolates. Errors detected in laboratories with more than 77% accuracy were associated with electrophoresis running conditions and an unspecific amplicon produced by a single strain. Lower accuracy was mainly related to inappropriate use of DNA markers and insufficient training in interpretation of patterns. In conclusion, the PRA method was readily implemented in some Latin American and Caribbean laboratories of mycobacteria, but improvements in critical points, as gel running conditions and training in interpretiation of patterns, are needed in order to improve accuracy. In others, improvement in critical points is still necessary. 相似文献
33.
Gamma carbonic anhydrases in plant mitochondria 总被引:1,自引:0,他引:1
Clifton R Lister R Parker KL Sappl PG Elhafez D Millar AH Day DA Whelan J 《Plant molecular biology》2005,58(2):193-212
Plant mitochondria contain non-phosphorylating bypasses of the respiratory chain, catalysed by the alternative oxidase (AOX) and alternative NADH dehydrogenases (NDH), as well as uncoupling (UCP) protein. Each of these components either circumvents or short-circuits proton translocation pathways, and each is encoded by a small gene family in Arabidopsis. Whole genome microarray experiments were performed with suspension cell cultures to examine the effects of various 3 h treatments designed to induce abiotic stress. The expression of over 60 genes encoding components of the classical, phosphorylating respiratory chain and tricarboxylic acid cycle remained largely constant when cells were subjected to a broad range of abiotic stresses, but expression of the alternative components responded differentially to the various treatments. In detailed time-course quantitative PCR analysis, specific members of both AOX and NDH gene families displayed coordinated responses to treatments. In particular, the co-expression of AOX1a and NDB2 observed under a number of treatments suggested co-regulation that may be directed by common sequence elements arranged hierarchically in the upstream promoter regions of these genes. A series of treatment sets were identified, representing the response of specific AOX and NDH genes to mitochondrial inhibition, plastid inhibition and abiotic stresses. These treatment sets emphasise the multiplicity of pathways affecting alternative electron transport components in plants.Supplementary material to this paper is available in electronic form at
http://dx.doi.org/10.1007/s11103-005-5514-7 相似文献
34.
35.
Background and aims
Species in plant communities segregate along fine-scale hydrological gradients. Although this phenomenon is not unique to fynbos, this community regenerates after fire and therefore provides an opportunity to study the ecological genesis of hydrological niche segregation.Methods
Following wildfires at two field sites where we had previously mapped the vegetation and monitored the hydrology, seeds were moved experimentally in >2500 intact soil cores up and down soil-moisture gradients to test the hypothesis that hydrological niche segregation is established during the seedling phase of the life cycle. Seedling numbers and growth were then monitored and they were identified using DNA bar-coding, the first use of this technology for an experiment of this kind.Key Results
At the site where niche segregation among Restionaceae had previously been found, the size of seedlings was significantly greater, the wetter the location into which they were moved, regardless of the soil moisture status of their location of origin, or of the species. Seedling weight was also significantly greater in a competition treatment where the roots of other species were excluded. No such effects were detected at the control site where niche segregation among Restionaceae was previously found to be absent.Conclusions
The finding that seedling growth on hydrological gradients in the field is affected by soil moisture status and by root competition shows that hydrological niche segregation could potentially originate in the seedling stage. The methodology, applied at a larger scale and followed-through for a longer period, could be used to determine whether species are differently affected by soil moisture. 相似文献36.
Araya Chochai Ilia J. Leitch fls Martin J. Ingrouille Michael F. Fay fls 《Botanical journal of the Linnean Society. Linnean Society of London》2012,170(2):176-196
Phylogenetic relationships in the genus Paphiopedilum were studied using nuclear ribosomal internal transcribed spacer (ITS) and plastid sequence data. The results confirm that the genus Paphiopedilum is monophyletic, and the division of the genus into three subgenera Parvisepalum, Brachypetalum and Paphiopedilum is well supported. Four sections of subgenus Paphiopedilum (Pardalopetalum, Cochlopetalum, Paphiopedilum and Barbata) are recovered as in a recent infrageneric treatment, with strong support. Section Coryopedilum is also recovered, with low bootstrap but high posterior probability values for support of monophyly. Relationships in section Barbata remain unresolved, and short branch lengths and the narrow geographical distribution of many species in the section suggest that it possibly underwent rapid radiation. Mapping chromosome and genome size data (including some new genome size measurements) onto the phylogenetic framework shows that there is no clear trend in increase in chromosome number in the genus. However, the diploid chromosome number of 2n = 26 in subgenera Parvisepalum and Brachypetalum suggests that this is the ancestral condition, and higher chromosome numbers in sections Cochlopetalum and Barbata suggest that centric fission has possibly occurred in parallel in these sections. The trend for genome size evolution is also unclear, although species in section Barbata have larger genome sizes than those in other sections. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 170 , 176–196. 相似文献
37.
38.
Zahida Iqbal Syuntaro Hiradate Hiroshi Araya Yoshiharu Fujii 《Plant Growth Regulation》2004,43(3):245-250
Allelopathic potential of Ophiopogon japonicus was investigated. The methanolic extract of O. japonicus roots strongly inhibited root and hypocotyls growth of lettuce. Sequential partitioning of the methanol extract with organic solvents showed that the diethyl ether and n-butanol extract possess strong plant growth inhibitory activities. The allelopathic constituents of the diethyl ether extract were isolated and identified as salicylic acid and p-hydroxybenzoic acid by NMR spectroscopy. Both of these phenolic acids were found in the aqueous extracts of leaves as well. The concentration of salicylic acid in roots and leaves were estimated as 0.011 and 0.02%, respectively, and it inhibited the root and shoot of tested plants by 50% even at less than 3 ppm. The p-hydroxybenzoic acid on the other hand was in less abundance (0.005%) and inhibited the plant growth to a lesser extent. The biological activity of commercially available O-methyl derivatives of these phenolic acids was also determined to establish structure–activity relationship. Among these, salicylic acid was found to be the most active one. These results suggest that Ophiopogon japonicus produces plant growth inhibitors, which are responsible for its potential allelopathic activity. 相似文献
39.
40.
Cecilia Koenig Claudia Araya Cetna Skorin Claudio Valencia Andrés Toro Federico Leighton Manuel J Santos 《The journal of histochemistry and cytochemistry》2002,50(3):405-414
We demonstrated a neutral Mg-ATPase activity in human peroxisomal membranes. To establish the precise experimental conditions for detection of this ATPase, both cytochemical and biochemical characterizations were first carried out in liver peroxisomes from control and cipofibrate-treated rats. The results demonstrated an Mg-ATPase reaction in both normal and proliferated peroxisomes. The nucleotidase activity, with marked preference for ATP, was sensitive to the inhibitors N-ethylmaleimide and 7-chloro-4-nitro-benzo-2-oxadiazole (NBDCl). An ultrastructural cytochemical analysis was developed to evaluate the peroxisomal localization, which localized the reaction product to the peroxisomal membrane. These characteristics can help to differentiate the peroxisomal ATPase from the activity found in mitochondria and endoplasmic reticulum. The conditions established for detecting the rat peroxisomal ATPase were then applied to human peroxisomes isolated from liver and skin fibroblasts in culture. A similar Mg-ATPase activity was readily shown, both cytochemically and biochemically, in the membranes of human peroxisomes. These results, together with previous evidence, strongly support the presence of a specific ATPase in the human peroxisomal membrane. This ATPase may play a crucial role in peroxisome biogenesis. 相似文献