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41.
Our understanding of the evolutionary history and ecology of cave‐associated species has been driven historically by studies of morphologically adapted cave‐restricted species. Our understanding of the evolutionary history and ecology of nonrestricted cave species, troglophiles, is limited to a few studies, which present differing accounts of troglophiles’ relationship with the cave habitat, and its impact on population dynamics. Here, we used phylogenetics, demographic statistics, and population genetic methods to study lineage divergence, dates of divergence, and population structure in the Cave Salamander, Eurycea lucifuga, across its range. In order to perform these analyses, we sampled 233 individuals from 49 populations, using sequence data from three gene loci as well as genotyping data from 19 newly designed microsatellite markers. We find, as in many other species studied in a phylogeographic context, discordance between patterns inferred from mitochondrial relationships and those inferred by nuclear markers indicating a complicated evolutionary history in this species. Our results suggest Pleistocene‐based divergence among three main lineages within E. lucifuga corresponding to the western, central, and eastern regions of the range, similar to patterns seen in species separated in multiple refugia during climatic shifts. The conflict between mitochondrial and nuclear patterns is consistent with what we would expect from secondary contact between regional populations following expansion from multiple refugia. 相似文献
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为研究杉木在中国的分布特征及其对气候变化的响应模式,本研究基于现有分布记录,应用最大熵(MaxEnt)模型和地理信息系统方法,结合气候、地形等环境要素,预测杉木在当前和未来气候变化下的潜在适生区。结果表明: 影响杉木分布的最主要因素是年平均降水量,在当前气候下,杉木适生区合计面积328万km2,占全国陆地总面积的34.5%,低、中和高适生区分别占18.3%、29.7%与52.0%。在未来气候情景下,杉木生长的适宜性在我国总体上呈上升趋势,适生区面积随气候变化增大,且明显向北扩张,南方湿润亚热带地区形成集中连片高适生区。模型经受试者工作特征曲线检验,训练集平均受试者工作特征曲线下面积为0.91,可信度高。 相似文献
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T S Edgington 《Journal of immunology (Baltimore, Md. : 1950)》1971,106(3):673-680
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Biomarkers of neurodegenerative disorders: How good are they? 总被引:11,自引:0,他引:11
Biomarkers are very important indicators of normal and abnormal biological processes. Specific changes in pathologies,biochemistries and genetics can give us comprehensive information regarding the nature of any particular disease. A good biomarker should be precise and reliable, distinguishable between normal and interested disease, and differentiable between different diseases. It is believed that biomarkers have great potential in predicting chances for diseases, aiding in early diagnosis, and setting standards for the development of new remedies to treat diseases. New technologies have enabled scientists to identify biomarkers of several different neurodegenerative diseases. The followings, for instance,are only a few of the many new biomarkers that have been recently identified: the phosphorylated tau protein and aggregated β-amyloid peptide for Alzheimer‘s disease (AD), α-synuclein contained Lewy bodies and altered dopamine transporter (DAT) imaging for Parkinson‘s disease (PD), SOD mutations for familial amyotrophic lateral sclerosis (ALS), and CAG repeats resulted from Huntington‘s gene mutations in Huntington‘s disease (HD). This article will focus on the most-recent findings of biomarkers belonging to the four mentioned neurodegenerative diseases. 相似文献
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Tissue factor (TF), the receptor and cofactor for factor VIIa (VIIa) for cellular initiation of the coagulation protease cascade, drives thrombogenesis, inflammation, tumor cell metastasis, and the lethality of severe sepsis. To identify TF surface loci that can selectively inhibit substrate zymogen association and activation, TF(1-218), the extracellular domain, was used as the target for the phage display search. This resulted in selection of 59 clones from a phage gpVIII surface protein-expressed library of constrained combinatorial peptides. Of these, one encoding the peptide Glu-Cys-Leu-Arg-Ser-Val-Val-Thr-Cys on gpVIII most avidly bound TF(1-218), as did the synthetic peptide. Inhibition of binding was selective with an IC(50) of 30 nM for proteolytic activation of factor X by the TF(1-218)-VIIa complex. In contrast, there was no inhibition of factor IX activation. The selective inhibition of only factor X association with TF(1-218) will spare the intrinsic hemostatic pathway while attenuating the extrinsic thrombogenic pathway. This and related peptidyl structures provide the potential for the more precise identification of TF surface loci that mediate selective functional properties of the protein as well as a structural basis for the design of novel molecules for selectively attenuating initiation of the extrinsic limb of the coagulation protease cascade and other functions of TF. 相似文献
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FREDERIQUE LE ROUX GEMA LORENZO PIERRE PEYRET CORINNE AUDEMARD ANTONIO FIGUERAS CHRISTIAN VIVARÈS MANOLO GOUY FRANCK BERTHE 《The Journal of eukaryotic microbiology》2001,48(4):449-454
Marteilia refringens is one of the most significant pathogens of bivalve molluscs. Previous sequencing of the small subunit ribosomal RNA gene of M. refringens isolates derived from the infected mussels (Mytilus edulis and Mytilus galloprovinciallis) and the oyster (Ostrea edulis) in Europe did not reveal genetic polymorphisms despite indications from epizootiological data that distinct types may exist. We investigated the existence of polymorphisms in the internal transcribed spacer region of the ribosomal RNA genes. The sequences of this region proved to be clearly dimorphic among Marteilia from five sampling sites. The distribution of the two genetic types, named "O" and "M", appeared to be linked to the host species, oysters and mussels, respectively. We therefore support the recognition of two species of Marteilia in Europe and propose that the "O" type corresponds to M. refringens and the "M" type to M. maurini. 相似文献