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51.
J H Gillespie 《Molecular biology and evolution》1989,6(6):636-647
Recent efforts to estimate the index of dispersion [R(t)] of molecular evolution-i.e., the ratio of the variance in the number of substitutions on a lineage to the mean number-have suffered from an inability to adjust the data for lineage effects. These effects may include the generation-time dependency of the rate of evolution or improper assumptions about the branching pattern of a phylogenetic tree. In the present paper a method for correcting for lineage effects in the estimation of R(t) is presented for trees made up of three species. The recent data published by Li et al. for 20 loci in three orders of mammals is examined, and the average R(t), corrected for lineage effects, is shown to be 7.75 for replacement substitutions and 3.3 for silent substitutions. Thus the high values reported earlier may not be dismissed as due to generation-time effects or improper assumptions about phylogenies. Computer simulations are presented to give confidence in the estimate for replacement substitutions but also to demonstrate that the estimate for silent substitutions is sensitive to corrections for multiple substitutions and is not as reliable. This work's implications for our understanding of the mechanism of molecular evolution are discussed, and the arguments in favor of the hypothesis that replacement substitutions are mostly selected while silent substitutions are mostly neutral is presented. 相似文献
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Arnold Gillespie 《BMJ (Clinical research ed.)》1972,1(5793):150-152
The pharmacological phenomena of enhancement and potentiation of uterine response occur respectively when combinations of some prostaglandins and oxytocin are given serially and simultaneously to a patient. Employing these phenomena allows small doses of the drugs to achieve the same effects as a large dose given alone. In a pilot study of the use of the combination of prostaglandin and oxytocin for the induction of mid-trimester abortion seven of nine women were aborted within 48 hours. Side effects attributable to prostaglandin were eliminated or reduced in severity. 相似文献
54.
Susan R. Kennedy Sophia Tsau Rosemary Gillespie Henrik Krehenwinkel 《Molecular ecology》2020,29(5):1001-1015
Stable core microbial communities have been described in numerous animal species and are commonly associated with fitness benefits for their hosts. Recent research, however, highlights examples of species whose microbiota are transient and environmentally derived. Here, we test the effect of diet on gut microbial community assembly in the spider Badumna longinqua. Using 16S rRNA gene amplicon sequencing combined with quantitative PCR, we analyzed diversity and abundance of the spider's gut microbes, and simultaneously characterized its prey communities using nuclear rRNA markers. We found a clear correlation between community similarity of the spider's insect prey and gut microbial DNA, suggesting that microbiome assembly is primarily diet‐driven. This assumption is supported by a feeding experiment, in which two types of prey—crickets and fruit flies—both substantially altered microbial diversity and community similarity between spiders, but did so in different ways. After cricket consumption, numerous cricket‐derived microbes appeared in the spider's gut, resulting in a rapid homogenization of microbial communities among spiders. In contrast, few prey‐associated bacteria were detected after consumption of fruit flies; instead, the microbial community was remodelled by environmentally sourced microbes, or abundance shifts of rare taxa in the spider's gut. The reshaping of the microbiota by both prey taxa mimicked a stable core microbiome in the spiders for several weeks post feeding. Our results suggest that the spider's gut microbiome undergoes pronounced temporal fluctuations, that its assembly is dictated by the consumed prey, and that different prey taxa may remodel the microbiota in drastically different ways. 相似文献
55.
Journal of Molecular Histology - The morphological and possible functional interactions between the connective tissue and enamel organ cells were examined during the maturation phase of enamel... 相似文献
56.
V. P. Edgcomb J. M. Bernhard D. Beaudoin S. Pruss P. V. Welander F. Schubotz S. Mehay A. L. Gillespie R. E. Summons 《Geobiology》2013,11(3):234-251
Microbialites (stromatolites and thrombolites) are mineralized mat structures formed via the complex interactions of diverse microbial‐mat communities. At Highborne Cay, in the Bahamas, the carbonate component of these features is mostly comprised of ooids. These are small, spherical to ellipsoidal grains characterized by concentric layers of calcium carbonate and organic matter and these sand‐sized particles are incorporated with the aid of extra‐cellular polymeric substances (EPS), into the matrix of laminated stromatolites and clotted thrombolite mats. Here, we present a comparison of the bacterial diversity within oolitic sand samples and bacterial diversity previously reported in thrombolitic and stromatolitic mats of Highborne Cay based on analysis of clone libraries of small subunit ribosomal RNA gene fragments and lipid biomarkers. The 16S‐rRNA data indicate that the overall bacterial diversity within ooids is comparable to that found within thrombolites and stromatolites of Highborne Cay, and this significant overlap in taxonomic groups suggests that ooid sands may be a source for much of the bacterial diversity found in the local microbialites. Cyanobacteria were the most diverse taxonomic group detected, followed by Alphaproteobacteria, Gammaproteobacteria, Planctomyces, Deltaproteobacteria, and several other groups also found in mat structures. The distributions of intact polar lipids, the fatty acids derived from them, and bacteriohopanepolyols provide broad general support for the bacterial diversity identified through analysis of nucleic acid clone libraries. 相似文献
57.
John Paul Wanner Roopashree Subbaiah Yelenna Skomorovska-Prokvolit Yousef Shishani Eric Boilard Sujatha Mohan Robert Gillespie Masaru Miyagi Reuben Gobezie 《Arthritis research & therapy》2013,15(6):R180
Introduction
The development of effective treatments for osteoarthritis (OA) has been hampered by a poor understanding of OA at the cellular and molecular levels. Emerging as a disease of the ''whole joint’, the importance of the biochemical contribution of various tissues, including synovium, bone and articular cartilage, has become increasingly significant. Bathing the entire joint structure, the proteomic analysis of synovial fluid (SF) from osteoarthritic shoulders offers a valuable ''snapshot’ of the biologic environment throughout disease progression. The purpose of this study was to identify differentially expressed proteins in early and late shoulder osteoarthritic SF in comparison to healthy SF.Methods
A quantitative 18O labeling proteomic approach was employed to identify the dysregulated SF proteins in early (n = 5) and late (n = 4) OA patients compared to control individuals (n = 5). In addition, ELISA was used to quantify six pro-inflammatory and two anti-inflammatory cytokines.Results
Key results include a greater relative abundance of proteins related to the complement system and the extracellular matrix in SF from both early and late OA. Pathway analyses suggests dysregulation of the acute phase response, liver x receptor/retinoid x receptor (LXR/RXR), complement system and coagulation pathways in both early and late OA. The network related to lipid metabolism was down-regulated in both early and late OA. Inflammatory cytokines including interleukin (IL) 6, IL 8 and IL 18 were up-regulated in early and late OA.Conclusions
The results suggest a dysregulation of wound repair pathways in shoulder OA contributing to the presence of a ''chronic wound’ that progresses irreversibly from early to later stages of OA. Protease inhibitors were downregulated in late OA suggesting uncontrolled proteolytic activity occurring in late OA. These results contribute to the theory that protease inhibitors represent promising therapeutic agents which could limit proteolytic activity that ultimately leads to cartilage destruction. 相似文献58.
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60.
Shawnita Sealy-Jefferson Brenda W. Gillespie Allison E. Aiello Mary N. Haan Lewis B. Morgenstern Lynda D. Lisabeth 《PloS one》2013,8(6)