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121.
Freshwater sphaeriid bivalves are poorly known ecologically, particularly uncommon species such as Pisidium pseudosphaerium (UK RDB (Red Data Book) staus = ‘rare’). In the UK, this species occupies grazing marsh where conservation opportunities might be shared with other threatened molluscs. We surveyed sphaeriids including P. pseudosphaerium and snails in 106 drainage ditches in SE England in 1999. P. pseudosphaerium occupied over half the ditches surveyed, at slightly elevated BOD (6 ± 7 mg l−1 sd) but reduced calcium (64 ± 31 mg l−1) and nitrate (0.5 ± 1.2 mg l−1). As part of a sphaeriid assemblage comprising Sphaerium corneum, Musculium lacustre and Pisidium obtusale (=Assemblage 1), P. pseudosphaerium occurred in ditches with floating vegetation and abundant snails of conservation importance, co-occurring significantly with either Valvata macrostoma (RDB ‘vulnerable’) or Anisus vorticulus (RDB: ‘vulnerable’). A more diverse sphaeriid assemblage (=Assemblage 2) included species common in wider, deeper ditches with open water. We suggest that traditional ditch management can support both rare and representative snails and bivalves on grazing marsh. Quasi-traditional and rotational ditch clearance will favour common sphaeriids and pioneer snails during early succession; P. pseudosphaerium, V. macrostoma, A. vorticulus during mid-succession; and the snail Segmentina nitida (RDB: ‘Endangered’) in late successional ditches. In common with threatened snails, P. pseudosphaerium will also benefit from reduced eutrophication. We recommend that P. pseudosphaerium retain RDB status to ensure protection and to emphasise the need for improved ecological information. 相似文献
122.
Recent studies have suggested that a high-density single nucleotide polymorphism (SNP) marker set could provide equivalent or even superior information compared with currently used microsatellite (STR) marker sets for gene mapping by linkage. The focus of this study was to compare results obtained from linkage analyses involving extended pedigrees with STR and single-nucleotide polymorphism (SNP) marker sets. We also wanted to compare the performance of current linkage programs in the presence of high marker density and extended pedigree structures. One replicate of the Genetic Analysis Workshop 14 (GAW14) simulated extended pedigrees (n = 50) from New York City was analyzed to identify the major gene D2. Four marker sets with varying information content and density on chromosome 3 (STR [7.5 cM]; SNP [3 cM, 1 cM, 0.3 cM]) were analyzed to detect two traits, the original affection status, and a redefined trait more closely correlated with D2. Multipoint parametric and nonparametric linkage analyses (NPL) were performed using programs GENEHUNTER, MERLIN, SIMWALK2, and S.A.G.E. SIBPAL. Our results suggested that the densest SNP map (0.3 cM) had the greatest power to detect linkage for the original trait (genetic heterogeneity), with the highest LOD score/NPL score and mapping precision. However, no significant improvement in linkage signals was observed with the densest SNP map compared with STR or SNP-1 cM maps for the redefined affection status (genetic homogeneity), possibly due to the extremely high information contents for all maps. Finally, our results suggested that each linkage program had limitations in handling the large, complex pedigrees as well as a high-density SNP marker set. 相似文献
123.
Two distinct alcohol dehydrogenases participate in butane metabolism by Pseudomonas butanovora
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The involvement of two primary alcohol dehydrogenases, BDH and BOH, in butane utilization in Pseudomonas butanovora (ATCC 43655) was demonstrated. The genes coding for BOH and BDH were isolated and characterized. The deduced amino acid sequence of BOH suggests a 67-kDa alcohol dehydrogenase containing pyrroloquinoline quinone (PQQ) as cofactor and in the periplasm (29-residue leader sequence). The deduced amino acid sequence of BDH is consistent with a 70.9-kDa, soluble, periplasmic (37-residue leader sequence) alcohol dehydrogenase containing PQQ and heme c as cofactors. BOH and BDH mRNAs were induced whenever the cell's 1-butanol oxidation activity was induced. When induced with butane, the gene for BOH was expressed earlier than the gene for BDH. Insertional disruption of bdh or boh affected adversely, but did not eliminate, butane utilization by P. butanovora. The P. butanovora mutant with both genes boh and bdh inactivated was unable to grow on butane or 1-butanol. These cells, when grown in citrate and incubated in butane, developed butane oxidation capability and accumulated 1-butanol. The enzyme activity of BOH was characterized in cell extracts of the P. butanovora strain with bdh disrupted. Unlike BDH, BOH oxidized 2-butanol. The results support the involvement of two distinct NAD(+)-independent, PQQ-containing alcohol dehydrogenases, BOH (a quinoprotein) and BDH (a quinohemoprotein), in the butane oxidation pathway of P. butanovora. 相似文献
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127.
Maria M. Aleman Lori A. Holle Katherine G. Stember Christa I. Devette Dougald M. Monroe Alisa S. Wolberg 《PloS one》2015,10(4)
Transglutaminases are a superfamily of isoenzymes found in cells and plasma. These enzymes catalyze the formation of ε-N-(γ-glutamyl)-lysyl crosslinks between proteins. Cystamine blocks transglutaminase activity and is used in vitro in human samples and in vivo in mice and rats in studies of coagulation, immune dysfunction, and inflammatory disease. These studies have suggested cystamine blocks fibrin crosslinking and has anti-inflammatory effects, implicating transglutaminase activity in the pathogenesis of several diseases. We measured the effects of cystamine on fibrin crosslinking, tissue factor-triggered plasma clot formation and thrombin generation, and coagulation factor enzymatic activity. At concentrations that blocked fibrin crosslinking, cystamine also inhibited plasma clot formation and reduced thrombin generation. Cystamine inhibited the amidolytic activity of coagulation factor XI and thrombin towards chromogenic substrates. These findings demonstrate that cystamine exhibits anticoagulant activity during coagulation. Given the close relationship between coagulation and inflammation, these findings suggest prior studies that used cystamine to implicate transglutaminase activity in disease pathogenesis warrant re-examination. 相似文献
128.
Helen Earley Grainne Lennon Aine Balfe Michelle Kilcoyne Marguerite Clyne Lokesh Joshi Stephen Carrington Sean T. Martin J. Calvin Coffey Desmond C. Winter P. Ronan O’Connell 《PloS one》2015,10(10)
Background
Akkermansia muciniphila and Desulfovibrio spp. are commensal microbes colonising the mucus gel layer of the colon. Both species have the capacity to utilise colonic mucin as a substrate. A. muciniphila degrades colonic mucin, while Desulfovibrio spp. metabolise the sulfate moiety of sulfated mucins. Altered abundances of these microorganisms have been reported in ulcerative colitis (UC). However their capacity to bind to human colonic mucin, and whether this binding capacity is affected by changes in mucin associated with UC, remain to be defined.Methods
Mucin was isolated from resected colon from control patients undergoing resection for colonic cancer (n = 7) and patients undergoing resection for UC (n = 5). Isolated mucin was purified and printed onto mucin microarrays. Binding of reference strains and three clinical isolates of A. muciniphila and Desulfovibrio spp. to purified mucin was investigated.Results
Both A. muciniphila and Desulfovibro spp. bound to mucin. The reference strain and all clinical isolates of A. muciniphila showed increased binding capacity for UC mucin (p < .005). The Desulfovibrio reference strain showed increased affinity for UC mucin. The mucin binding profiles of clinical isolates of Desulfovibrio spp. were specific to each isolate. Two isolates showed no difference in binding. One UC isolate bound with increased affinity to UC mucin (p < .005).Conclusion
These preliminary data suggest that differences exist in the mucin binding capacity of isolates of A. muciniphila and Desulfovibrio spp. This study highlights the mucin microarray platform as a means of studying the ability of bacteria to interact with colonic mucin in health and disease. 相似文献129.
Krista A. Dent Kimberly J. Christie Nicole Bye Harleen S. Basrai Alisa Turbic Mark Habgood Holly S. Cate Ann M. Turnley 《PloS one》2015,10(3)
Oligodendrocytes are responsible for producing and maintaining myelin throughout the CNS. One of the pathological features observed following traumatic brain injury (TBI) is the progressive demyelination and degeneration of axons within white matter tracts. While the effect of TBI on axonal health has been well documented, there is limited information regarding the response of oligodendrocytes within these areas. The aim of this study was to characterize the response of both mature oligodendrocytes and immature proliferative oligodendrocyte lineage cells across a 3 month timecourse following TBI. A computer-controlled cortical impact model was used to produce a focal lesion in the left motor cortex of adult mice. Immunohistochemical analyses were performed at 48 hours, 7 days, 2 weeks, 5 weeks and 3 months following injury to assess the prevalence of mature CC-1+ oligodendrocyte cell death, immature Olig2+ cell proliferation and longer term survival in the corpus callosum and external capsule. Decreased CC-1 immunoreactivity was observed in white matter adjacent to the site of injury from 2 days to 2 weeks post TBI, with ongoing mature oligodendrocyte apoptosis after this time. Conversely, proliferation of Olig2+ cells was observed as early as 48 hours post TBI and significant numbers of these cells and their progeny survived and remained in the external capsule within the injured hemisphere until at least 3 months post injury. These findings demonstrate that immature oligodendrocyte lineage cells respond to TBI by replacing oligodendrocytes lost due to damage and that this process occurs for months after injury. 相似文献
130.
Baligh R. Yehia Alisa J. Stephens-Shields John A. Fleishman Stephen A. Berry Allison L. Agwu Joshua P. Metlay Richard D. Moore W. Christopher Mathews Ank Nijhawan Richard Rutstein Aditya H. Gaur Kelly A. Gebo HIV Research Network 《PloS one》2015,10(6)