全文获取类型
收费全文 | 134篇 |
免费 | 18篇 |
国内免费 | 32篇 |
出版年
2023年 | 3篇 |
2022年 | 6篇 |
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 5篇 |
2018年 | 1篇 |
2017年 | 4篇 |
2016年 | 3篇 |
2015年 | 6篇 |
2014年 | 6篇 |
2013年 | 4篇 |
2012年 | 14篇 |
2011年 | 17篇 |
2010年 | 13篇 |
2009年 | 8篇 |
2008年 | 10篇 |
2007年 | 8篇 |
2006年 | 6篇 |
2005年 | 9篇 |
2004年 | 7篇 |
2003年 | 3篇 |
2002年 | 7篇 |
2000年 | 4篇 |
1999年 | 8篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1986年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1978年 | 1篇 |
1971年 | 1篇 |
1879年 | 1篇 |
排序方式: 共有184条查询结果,搜索用时 182 毫秒
1.
2.
Acetate,methanol and carbon dioxide as substrates for growth of Methanosarcina barkeri 总被引:10,自引:0,他引:10
T. J. Hutten H. C. M. Bongaerts C. van der Drift G. D. Vogels 《Antonie van Leeuwenhoek》1980,46(6):601-610
Methanosarcina barkeri grows in defined media with acetate, methanol or carbon dioxide as carbon sources. Methanol is used for methanogenesis at a 5 times higher rate as compared with the other substrates. M. barkeri can use the substrates simultaneously, but due to acidification or alkalification of the medium during growth on methanol or acetate, respectively, growth and methanogenesis may stop before the substrates are exhausted. Growth and methanogenesis on methanol or acetate are inhibited by the presence of an excess of H2; the inhibition is abolished by the addition of carbon dioxide, which probably serves as an essential source of cell carbon, in the absence of which methano-genesis ceases. 相似文献
3.
4.
Larson Boundenga Boris Makanga Benjamin Ollomo Aude Gilabert Virginie Rougeron Bertrand Mve-Ondo Céline Arnathau Patrick Durand Nancy Diamella Moukodoum Alain-Prince Okouga Lucresse Delicat-Loembet Lauriane Yacka-Mouele Nil Rahola Eric Leroy Cheikh Tidiane BA Francois Renaud Franck Prugnolle Christophe Paupy 《PloS one》2016,11(2)
Re-examination, using molecular tools, of the diversity of haemosporidian parasites (among which the agents of human malaria are the best known) has generally led to rearrangements of traditional classifications. In this study, we explored the diversity of haemosporidian parasites infecting vertebrate species (particularly mammals, birds and reptiles) living in the forests of Gabon (Central Africa), by analyzing a collection of 492 bushmeat samples. We found that samples from five mammalian species (four duiker and one pangolin species), one bird and one turtle species were infected by haemosporidian parasites. In duikers (from which most of the infected specimens were obtained), we demonstrated the existence of at least two distinct parasite lineages related to Polychromophilus species (i.e., bat haemosporidian parasites) and to sauropsid Plasmodium (from birds and lizards). Molecular screening of sylvatic mosquitoes captured during a longitudinal survey revealed the presence of these haemosporidian parasite lineages also in several Anopheles species, suggesting a potential role in their transmission. Our results show that, differently from what was previously thought, several independent clades of haemosporidian parasites (family Plasmodiidae) infect mammals and are transmitted by anopheline mosquitoes. 相似文献
5.
Claire E Naylor Claire Bagnéris Paul G DeCaen Altin Sula Antonella Scaglione David E Clapham BA Wallace 《The EMBO journal》2016,35(8):820-830
Voltage‐gated sodium channels are essential for electrical signalling across cell membranes. They exhibit strong selectivities for sodium ions over other cations, enabling the finely tuned cascade of events associated with action potentials. This paper describes the ion permeability characteristics and the crystal structure of a prokaryotic sodium channel, showing for the first time the detailed locations of sodium ions in the selectivity filter of a sodium channel. Electrostatic calculations based on the structure are consistent with the relative cation permeability ratios (Na+ ≈ Li+ ≫ K+, Ca2+, Mg2+) measured for these channels. In an E178D selectivity filter mutant constructed to have altered ion selectivities, the sodium ion binding site nearest the extracellular side is missing. Unlike potassium ions in potassium channels, the sodium ions in these channels appear to be hydrated and are associated with side chains of the selectivity filter residues, rather than polypeptide backbones. 相似文献
6.
van der Veen BA Uitdehaag JC Dijkstra BW Dijkhuizen L 《Biochimica et biophysica acta》2000,1543(2):336-360
7.
Claudia G Petersen Fabiana C Massaro Ana L Mauri Joao BA Oliveira Ricardo LR Baruffi Jose G FrancoJr 《Reproductive biology and endocrinology : RB&E》2010,8(1):149
Background
The present study aimed to evaluate the efficacy of the hyaluronic acid (HA) binding assay in the selection of motile spermatozoa with normal morphology at high magnification (8400x). 相似文献8.
van der Steeg WA Hovingh GK Klerkx AH Hutten BA Nootenboom IC Levels JH van Tol A Dallinga-Thie GM Zwinderman AH Kastelein JJ Kuivenhoven JA 《Journal of lipid research》2007,48(3):674-682
It is unclear whether cholesteryl ester transfer protein (CETP) contributes to high density lipoprotein cholesterol (HDL-C) levels in hyperalphalipoproteinemia (HALP) in Caucasians. Moreover, even less is known about the effects of hereditary CETP deficiency in non-Japanese. We studied 95 unrelated Caucasian individuals with HALP. No correlations between CETP concentration or activity and HDL-C were identified. Screening for CETP gene defects led to the identification of heterozygosity for a novel splice site mutation in one individual. Twenty-five heterozygotes for this mutation showed reduced CETP concentration (-40%) and activity (-50%) and a 35% increase of HDL-C compared with family controls. The heterozygotes presented with an isolated high HDL-C, whereas the remaining subjects exhibited a typical high HDL-C/low-triglyceride phenotype. The increase of HDL-C in the CETP-deficient heterozygotes was primarily attributable to increased high density lipoprotein containing apolipoprotein A-I and A-II (LpAI:AII) levels, contrasting with an increase in both high density lipoprotein containing apolipoprotein A-I only and LpAI:AII in the other group. This study suggests the absence of a relationship between CETP and HDL-C levels in Caucasians with HALP. The data furthermore indicate that genetic CETP deficiency is rare among Caucasians and that this disorder presents with a phenotype that is different from that of subjects with HALP who have no mutation in the CETP gene. 相似文献
9.
CRM1 (chromosome region maintenance 1; also referred to as exportin1 or Xpo1) is a member of the importin beta superfamily of nuclear transport receptors, recognizing proteins bearing a leucine-rich nuclear export sequence. CRM1 is the major receptor for the export of proteins out of the nucleus and is also required for transport of many RNAs. Besides its established role in nuclear export, CRM1 is also implicated in various steps during mitosis, widening its functional spectrum within the cell. 相似文献
10.
辽宁是东北林蛙Rana dybowskii主要分布地之一,种群数量巨大,其群体遗传多样性有待评估.本研究应用ISSR标记技术对东北林蛙4个种群105个样本进行研究,5个引物共获得44条清晰谱带,4个种群的多态位点率均大于75%,Nei's基因多样性为0.2851,Shannon信息指数为0.4476,显示了较高的遗传多样性.对遗传分化系数、Nei's遗传距离、AMOVA分子变异巢式方差分析和F-统计量等遗传参数的统计结果表明,辽宁东北林蛙种群间已经出现一定程度的遗传分化,分析认为,自然屏障(高山和平原等)以及栖息地片段化是其遗传分化形成的主要因素. 相似文献