全文获取类型
收费全文 | 2622篇 |
免费 | 248篇 |
国内免费 | 1篇 |
专业分类
2871篇 |
出版年
2023年 | 16篇 |
2022年 | 34篇 |
2021年 | 104篇 |
2020年 | 47篇 |
2019年 | 66篇 |
2018年 | 67篇 |
2017年 | 57篇 |
2016年 | 88篇 |
2015年 | 143篇 |
2014年 | 173篇 |
2013年 | 210篇 |
2012年 | 238篇 |
2011年 | 224篇 |
2010年 | 125篇 |
2009年 | 135篇 |
2008年 | 166篇 |
2007年 | 151篇 |
2006年 | 125篇 |
2005年 | 114篇 |
2004年 | 66篇 |
2003年 | 77篇 |
2002年 | 71篇 |
2001年 | 38篇 |
2000年 | 30篇 |
1999年 | 29篇 |
1998年 | 19篇 |
1997年 | 15篇 |
1996年 | 11篇 |
1995年 | 19篇 |
1994年 | 18篇 |
1993年 | 16篇 |
1992年 | 13篇 |
1991年 | 16篇 |
1990年 | 20篇 |
1989年 | 13篇 |
1988年 | 10篇 |
1987年 | 5篇 |
1986年 | 10篇 |
1985年 | 7篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 6篇 |
1974年 | 5篇 |
1973年 | 11篇 |
1972年 | 4篇 |
1970年 | 4篇 |
1969年 | 9篇 |
1968年 | 4篇 |
排序方式: 共有2871条查询结果,搜索用时 15 毫秒
991.
992.
993.
Atika Meklat Noureddine Bouras Abdelghani Zitouni Florence Mathieu Ahmed Lebrihi Peter Schumann Cathrin Spröer Hans-Peter Klenk Nasserdine Sabaou 《Antonie van Leeuwenhoek》2013,104(3):301-307
A novel halophilic actinomycete strain, H23T, was isolated from a Saharan soil sample collected in Djamâa (Oued Righ region), El-Oued province, South Algeria. Strain H23T was identified as a member of the genus Actinopolyspora by a polyphasic approach. Phylogenetic analysis showed that strain H23T had 16S rRNA gene sequence similarities ranging from 97.8 % (Actinopolyspora xinjiangensis TRM 40136T) to 94.8 % (Actinopolyspora mortivallis DSM 44261T). The strain grew optimally at pH 6.0–7.0, 28–32 °C and in the presence of 15–25 % (w/v) NaCl. The substrate mycelium was well developed and fragmented with age. The aerial mycelium produced long, straight or flexuous spore chains with non-motile, smooth-surfaced and rod-shaped spores. Strain H23T had MK-10 (H4) and MK-9 (H4) as the predominant menaquinones. The whole micro-organism hydrolysates mainly consisted of meso-diaminopimelic acid, galactose and arabinose. The diagnostic phospholipid detected was phosphatidylcholine. The major cellular fatty acids were anteiso-C17:0 (37.4 %), iso-C17:0 (14.8 %), iso-C15:0 (14.2 %), and iso-C16:0 (13.9 %). The genotypic and phenotypic data show that the strain represents a novel species of the genus Actinopolyspora, for which the name Actinopolyspora righensis sp. nov. is proposed, with the type strain H23T (=DSM 45501T = CCUG 63368T = MTCC 11562T). 相似文献
994.
Stéphane Compant Saima Muzammil Ahmed Lebrihi Florence Mathieu 《Plant and Soil》2013,370(1-2):583-591
Background and aim
There is currently a gap of knowledge regarding whether some beneficial bacteria isolated from desert soils can colonize epi- and endophytically plants of temperate regions. In this study, the early steps of the colonization process of one of these bacteria, Saccharothrix algeriensis NRRL B-24137, was studied on grapevine roots to determine if this beneficial strain can colonize a non-natural host plant. An improved method of fluorescence in situ hybridization (FISH), the double labeling of oligonucleotide probes (DOPE)-FISH technique was used to visualize the colonization behavior of such bacteria as well as to determine if the method could be used to track microbes on and inside plants.Methods
A probe specific to Saccharothrix spp. was firstly designed. Visualization of the colonization behavior of S. algeriensis NRRL B-24137 on and inside roots of grapevine plants was then carried out with DOPE-FISH microscopy.Results
The results showed that 10 days after inoculation, the strain could colonize the root hair zone, root elongation zone, as well as root emergence sites by establishing different forms of bacterial structures as revealed by the DOPE-FISH technique. Further observations showed that the strain could be also endophytic inside the endorhiza of grapevine plants.Conclusions
Taking into account the natural niches of this beneficial strain, this study exemplifies that, in spite of its isolation from desert soil, the strain can establish populations as well as subpopulations on and inside grapevine plants and that the DOPE-FISH tool can allow to detect it. 相似文献995.
Isidro Toro-Moyano Bienvenido Martínez-Navarro Jordi Agustí Caroline Souday José María Bermúdez de Castro María Martinón-Torres Beatriz Fajardo Mathieu Duval Christophe Falguères Oriol Oms Josep Maria Parés Pere Anadón Ramón Julià José Manuel García-Aguilar Anne-Marie Moigne María Patrocinio Espigares Sergio Ros-Montoya Paul Palmqvist 《Journal of human evolution》2013
The Orce region has one of the best late Pliocene and early Pleistocene continental paleobiological records of Europe. It is situated in the northeastern sector of the intramontane Guadix-Baza Basin (Granada, Andalusia, southern Spain). Here we describe a new fossil hominin tooth from the site of Barranco León, dated between 1.02 and 1.73 Ma (millions of years ago) by Electron Spin Resonance (ESR), which, in combination with paleomagnetic and biochronologic data, is estimated to be close to 1.4 Ma. While the range of dates obtained from these various methods overlaps with those published for the Sima del Elefante hominin locality (1.2 Ma), the overwhelming majority of evidence points to an older age. Thus, at the moment, the Barranco León hominin is the oldest from Western Europe. 相似文献
996.
Catheleyne D'hondt Jegan Iyyathurai Mathieu Vinken Vera Rogiers Luc Leybaert Bernard Himpens Geert Bultynck 《Biology of the cell / under the auspices of the European Cell Biology Organization》2013,105(9):373-398
Connexin (Cx) and pannexin (Panx) proteins form large conductance channels, which function as regulators of communication between neighbouring cells via gap junctions and/or hemichannels. Intercellular communication is essential to coordinate cellular responses in tissues and organs, thereby fulfilling an essential role in the spreading of signalling, survival and death processes. The functional properties of gap junctions and hemichannels are modulated by different physiological and pathophysiological stimuli. At the molecular level, Cxs and Panxs function as multi‐protein channel complexes, regulating their channel localisation and activity. In addition to this, gap junctional channels and hemichannels are modulated by different post‐translational modifications (PTMs), including phosphorylation, glycosylation, proteolysis, N‐acetylation, S‐nitrosylation, ubiquitination, lipidation, hydroxylation, methylation and deamidation. These PTMs influence almost all aspects of communicating junctional channels in normal cell biology and pathophysiology. In this review, we will provide a systematic overview of PTMs of communicating junction proteins and discuss their effects on Cx and Panx‐channel activity and localisation. 相似文献
997.
M. Mathieu J. P. Bergeron A. M. Alayse Danet 《Invertebrate reproduction & development.》2013,57(6):337-343
Relationships between specific activity of the mantle ATC and gametogenic cycle are considered in the mussel Mytilus edulis. The hypothesis of a retroactive action of ripe gametes upon neurosecretory cells is suggested. 相似文献
998.
The ability to perceive and avoid harmful substances or stimuli is key to an organism's survival. The neuronal cognate of the perception of pain is known as nociception, and the reflexive motion to avoid pain is termed the nocifensive response. As the nocifensive response is an ancient and evolutionarily conserved behavioral response to nociceptive stimuli, it is amenable to study in relatively simple and genetically tractable model systems such as Drosophila. Recent studies have taken advantage of the useful properties of Drosophila larvae to begin elucidating the neuronal connectivity and molecular machinery underlying the nocifensive response. However, these studies have primarily utilized the third-instar larval stage, and many mutations that potentially influence nociception survive only until earlier larval stages. Here we characterize the nocifensive responses of Drosophila throughout larval development and find dramatic changes in the nature of the behavior. Notably, we find that prior to the third instar, larvae are unable to perform the characteristic "corkscrew-like roll" behavior. Also, we identify an avoidance behavior consistent with a nocifensive response that is present immediately after larval hatching, representing a paradigm that may be useful in examining mutations with an early lethal phenotype. 相似文献
999.
1000.