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81.
Ken-ichiro Katsura‡ Elena B. Rodriguez de Turco† Jaroslava Folbergrov᧠Nicolas G. Bazan† Bo K. Siesjö 《Journal of neurochemistry》1993,61(5):1677-1684
Abstract— The objective of the present experiments was to correlate changes in cellular energy metabolism, dissipative ion fluxes, and lipolysis during the first 90 s of ischemia and, hence, to establish whether phospholipase A2 or phospholipase C is responsible for the early accumulation of phospholipid hydrolysis products. Ischemia was induced for 15–90 s in rats, extracellular K+ (K+ e ) was recorded, and neocortex was frozen in situ for measurements of labile tissue metabolites, free fatty acids, and diacylglycerides. Ischemia of 15-and 30-s duration gave rise to a decrease in phosphocreatine concentration and a decline in the ATP/free ADP ratio. Although these changes were accompanied by an activation of K+ conductances, there were no changes in free fatty acids until after 60s, when free arachidonic acid accumulated. An increase in other free fatty acids and in total diacylglyceride content did not occur until after anoxic depolarization. The results demonstrate that the early functional changes, such as activation of K+ conductances, are unrelated to changes in lipids or lipid mediators. They furthermore suggest that the initial lipolysis occurs via both phospholipase A2 and phospholipase C, which are activated when membrane depolarization leads to influx of calcium into cells. 相似文献
82.
Relationship between the levels of wheat-rye metaphase I chromosomal pairing and recombination revealed by GISH 总被引:3,自引:0,他引:3
The metaphase I and anaphase I stages of meiosis of wheat×rye hybrids carrying the ph1b mutation were analyzed by genomic in situ hybridization. This technique allows distinction between three different types of
wheat-rye associations in metaphase I configurations as well as detection of wheat-rye recombinant chromosomes in anaphase
I cells. The frequency of associations between wheat and rye chromosomes greatly exceeded the level of wheat-rye recombination
found in the three hybrids examined. Extremely distal associations, which account for about 50% of the total wheat-rye metaphase
I chromosomal pairing, can explain such a discrepancy between metaphase I and anaphase I data. It is further discussed whether
these associations reflect very distally located chiasmata or nonchiasmatic pairing. The sizes of the segments exchanged in
wheat-rye recombinant chromosomes provide cytological evidence that wheat-rye recombination is restricted to the distal chromosomal
regions.
Received: 24 August 1995; in revised form: 27 February 1996 / Accepted: 28 March 1996 相似文献
83.
84.
Kenneth J Warrington Elena P Jarpa Cynthia S Crowson Leslie T Cooper Gene G Hunder Eric L Matteson Sherine E Gabriel 《Arthritis research & therapy》2009,11(2):R50-6
Introduction
The present study was conducted to determine whether patients with polymyalgia rheumatica (PMR) are at an increased risk of peripheral arterial disease (PAD). 相似文献85.
Taras Y. Nechitaylo Michail M. Yakimov Miguel Godinho Kenneth N. Timmis Elena Belogolova Boris A. Byzov Alexander V. Kurakov David L. Jones Peter N. Golyshin 《Microbial ecology》2010,59(3):574-587
Earthworms ingest large amounts of soil and have the potential to radically alter the biomass, activity, and structure of
the soil microbial community. In this study, the diversity of eight bacterial groups from fresh soil, gut, and casts of the
earthworms Lumbricus terrestris and Aporrectodea caliginosa were studied by single-strand conformation polymorphism (SSCP) analysis using both newly designed 16S rRNA gene-specific
primer sets targeting Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Deltaproteobacteria, Bacteroidetes, Verrucomicrobia,
Planctomycetes, and Firmicutes and a conventional universal primer set for SSCP, with RNA and DNA as templates. In parallel,
the study of the relative abundance of these taxonomic groups in the same samples was performed using fluorescence in situ
hybridization. Bacteroidetes, Alphaproteobacteria, and Betaproteobacteria were predominant in communities from the soil and
worm cast samples. Representatives of classes Flavobacteria and Sphingobacteria (Bacteroidetes) and Pseudomonas spp. (low-abundant Gammaproteobacteria) were detected in soil and worm cast samples with conventional and taxon-targeting
SSCP and through the sequence analysis of 16S rRNA clone libraries. Physiologically active unclassified Sphingomonadaceae
(Alphaproteobacteria) and Alcaligenes spp. (Betaproteobacteria) also maintained their diversities during transit through the earthworm intestine and were found
on taxon-targeting SSCP profiles from the soil and worm cast samples. In conclusion, our results suggest that some specific
bacterial taxonomic groups maintain their diversity and even increase their relative numbers during transit through the gastrointestinal
tract of earthworms. 相似文献
86.
Naeela Qureshi Harbans Bariana Kerrie Forrest Matthew Hayden Beat Keller Thomas Wicker Justin Faris Elena Salina Urmil Bansal 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2017,130(3):495-504
Key message
Fine mapping of Yr47 and Lr52 in chromosome arm 5BS of wheat identified close linkage of the marker sun180 to both genes and its robustness for marker-assisted selection was demonstrated.Abstract
The widely effective and genetically linked rust resistance genes Yr47 and Lr52 have previously been mapped in the short arm of chromosome 5B in two F3 populations (Aus28183/Aus27229 and Aus28187/Aus27229). The Aus28183/Aus27229 F3 population was advanced to generate an F6 recombinant inbred line (RIL) population to identify markers closely linked with Yr47 and Lr52. Diverse genomic resources including flow-sorted chromosome survey sequence contigs representing the orthologous region in Brachypodium distachyon, the physical map of chromosome arm 5BS, expressed sequence tags (ESTs) located in the 5BS6-0.81-1.00 deletion bin and resistance gene analog contigs of chromosome arm 5BS were used to develop markers to saturate the target region. Selective genotyping was also performed using the iSelect 90 K Infinium wheat SNP assay. A set of SSR, STS, gene-based and SNP markers were developed and genotyped on the Aus28183/Aus27229 RIL population. Yr47 and Lr52 are genetically distinct genes that mapped 0.4 cM apart in the RIL population. The SSR marker sun180 co-segregated with Lr52 and mapped 0.4 cM distal to Yr47. In a high resolution mapping population of 600 F2 genotypes Yr47 and Lr52 mapped 0.2 cM apart and marker sun180 was placed 0.4 cM distal to Lr52. The amplification of a different sun180 amplicon (195 bp) than that linked with Yr47 and Lr52 (200 bp) in 204 diverse wheat genotypes demonstrated its robustness for marker-assisted selection of these genes.87.
Size of genetic bottlenecks leading to virus fitness loss is determined by mean initial population fitness. 总被引:4,自引:11,他引:4 下载免费PDF全文
Genetic bottlenecks are important events in the genetic diversification of organisms and colonization of new ecological niches. Repeated bottlenecking of RNA viruses often leads to fitness losses due to the operation of Muller's ratchet. Herein we use vesicular stomatitis virus to determine the transmission population size which leads to fitness decreases of virus populations. Remarkably, the effective size of a genetic bottleneck associated with fitness loss is greater when the fitness of the parental population increases. For example, for starting virus populations with low fitness, population transfers of five-clone-to-five-clone passages resulted in a fitness increase. However, when a parental population with high fitness was transferred, 30-clone-to-30-clone passages were required simply to maintain fitness values. 相似文献
88.
Tato I Matilla I Arechaga I Zunzunegui S de la Cruz F Cabezon E 《The Journal of biological chemistry》2007,282(35):25569-25576
Conjugative systems contain an essential integral membrane protein involved in DNA transport called the Type IV coupling protein (T4CP). The T4CP of conjugative plasmid R388 is TrwB, a DNA-dependent ATPase. Biochemical and structural data suggest that TrwB uses energy released from ATP hydrolysis to pump DNA through its central channel by a mechanism similar to that used by F1-ATPase or ring helicases. For DNA transport, TrwB couples the relaxosome (a DNA-protein complex) to the secretion channel. In this work we show that TrwA, a tetrameric oriT DNA-binding protein and a component of the R388 relaxosome, stimulates TrwBDeltaN70 ATPase activity, revealing a specific interaction between the two proteins. This interaction occurs via the TrwA C-terminal domain. A 68-kDa complex between TrwBDeltaN70 and TrwA C-terminal domain was observed by gel filtration chromatography, consistent with a 1:1 stoichiometry. Additionally, electron microscopy revealed the formation of oligomeric TrwB complexes in the presence, but not in the absence, of TrwA protein. TrwBDeltaN70 ATPase activity in the presence of TrwA was further enhanced by DNA. Interestingly, maximal ATPase rates were achieved with TrwA and different types of dsDNA substrates. This is consistent with a role of TrwA in facilitating the interaction between TrwB and DNA. Our findings provide a new insight into the mechanism by which TrwB recruits the relaxosome for DNA transport. The process resembles the mechanism used by other DNA-dependent molecular motors, such as the RuvA/RuvB system, to be targeted to the DNA followed by hexamer assembly. 相似文献
89.
The identification of regulatory T (Treg) cells as important regulators of self-tolerance has opened up new therapeutic avenues for the treatment of several human diseases associated with Treg dysfunction, including autoimmune diseases and transplantation. Recent evidence indicates that vasoactive intestinal peptide (VIP), an anti-inflammatory neuropeptide with therapeutic potential in various immune disorders, participates in maintaining immune tolerance by a novel mechanism of inducing the generation of Treg cells. We propose a Treg-cell-based immunotherapy approach for resetting the balance of immune homeostasis, which takes advantage of novel functions of VIP in immunoregulation. 相似文献
90.