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61.
30 strains of xylanolytic thermophilic actinomycetes were isolated from composted grass and cattle manure and identified as members of the generaThermomonospora, Saccharomonospora, Microbispora, Streptomyces andActinomadura. Screening of these strains for extracellular xylanase indicated that strains ofSaccharomonospora andMicrobispora generally were poor xylanase producers (0.5–1.5 U/ml) whereas relatively high activities were observed in cultures ofStreptomyces andActionomadura (4–12 U/ml).A preliminary characterization of the enzymes of strains of the latter genera suggested that xylanases of all the strains ofActinomadura exhibited higher thermostabilities than those ofStreptomyces. To evaluate the potential of thermophilicActinomadura for industrial applications, xylanases of three strains were studied in more detail. The highest activity levels for xylanases were observed in cultures grown on xylan and wheat bran. The optimal pH and temperature for xylanase activities ranged from 6.0 to 7.0 and 70 to 80°C. The enzymes exhibited considerable thermostability at their optimum temperature. The half-lives at 75°C were in the range from 6.5 to 17h. Hydrolysis of xylan by extracellular xylanases yielded xylobiose, xylose and arabinose as principal products. Estimated by the amount of reducing sugars liberated the degree of hydrolysis was 55 to 65%. Complete utilization of xylan is presumably achieved by -xylosidase activities which could be shown to be largely cell-associated in the 3Actinomadura strains. 相似文献
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The nucleotide sequence of a segment of mtDNA from Rattus norvegiens (rat) which contains the genes for tRNAile, tRNAgl and tRNAf-met has been determined. A detailed comparison has been made between this sequence and the corresponding sequences of mouse, human and bovine mtDNAs with regard to the primary and secondary structure of the tRNA genes, the regions connecting the tRNA genes, and the regions flanking the tRNA genes which code for the carboxyl terminus of URF-1 and the amino terminus of URF-2. No differences were found in the nucleotide sequences of the genes for tRNAile, tRNAgln and tRNAf-met in mtDNAs from three different female lines of rats (SASCO-1, SASCO-2 and Wild-UT) that differ by substitutions of 0.8% to 1.8% of their total nucleotides. 相似文献
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Seven indolic alkaloids have been isolated from the stem bark of Crioceras dipladeniiflorus. One of them is new and has been called criocerine. Its structure, 7, has been established by use of physical data and chemical correlation with [Δ14]-vincamine. 相似文献
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Assassin bugs are one of the most successful clades of predatory animals based on their species numbers (∼6,800 spp.) and wide distribution in terrestrial ecosystems. Various novel prey capture strategies and remarkable prey specializations contribute to their appeal as a model to study evolutionary pathways involved in predation. Here, we reconstruct the most comprehensive reduviid phylogeny (178 taxa, 18 subfamilies) to date based on molecular data (5 markers). This phylogeny tests current hypotheses on reduviid relationships emphasizing the polyphyletic Reduviinae and the blood-feeding, disease-vectoring Triatominae, and allows us, for the first time in assassin bugs, to reconstruct ancestral states of prey associations and microhabitats. Using a fossil-calibrated molecular tree, we estimated divergence times for key events in the evolutionary history of Reduviidae. Our results indicate that the polyphyletic Reduviinae fall into 11–14 separate clades. Triatominae are paraphyletic with respect to the reduviine genus Opisthacidius in the maximum likelihood analyses; this result is in contrast to prior hypotheses that found Triatominae to be monophyletic or polyphyletic and may be due to the more comprehensive taxon and character sampling in this study. The evolution of blood-feeding may thus have occurred once or twice independently among predatory assassin bugs. All prey specialists evolved from generalist ancestors, with multiple evolutionary origins of termite and ant specializations. A bark-associated life style on tree trunks is ancestral for most of the lineages of Higher Reduviidae; living on foliage has evolved at least six times independently. Reduviidae originated in the Middle Jurassic (178 Ma), but significant lineage diversification only began in the Late Cretaceous (97 Ma). The integration of molecular phylogenetics with fossil and life history data as presented in this paper provides insights into the evolutionary history of reduviids and clears the way for in-depth evolutionary hypothesis testing in one of the most speciose clades of predators. 相似文献
69.
Edward B. Blanchard Maria L. Peters Christiane Hermann Shannon M. Turner Todd C. Buckley Kristine Barton Mark P. Dentinger 《Applied psychophysiology and biofeedback》1997,22(4):227-245
In order to test for the specific therapeutic effects of thermal biofeedback (TBF) for hand warming on vascular headache (HA),
70 patients with chronic vascular HA were randomly assigned to TBF for hand warming, TBF for hand cooling, TBF for stabilization
of hand temperature, or biofeedback to suppress alpha in the EEG. Patients in each condition initially had high levels of
expectation of therapeutic benefit and found the treatment rationales highly credible. Participants in each condition received
12 treatment sessions on a twice-per-week basis. Based on daily HA diary data gathered for 4 weeks prior to treatment and
4 weeks after treatment, HA Index was significantly (p=.003) reduced as was HA medication consumption. There were no differential
reducations in HA Index or Medication Index among the four conditions. Global self-reports of improvement gathered at the
end of the post-treatment monitoring period also did not differ among the four conditions. We were unable to demonstrate a
specific effect of TBF for hand warming on vascular HA activity. 相似文献
70.
Christiane Lacombe Viviane Viallard Stphane Schaak Herv Paris 《Biology of the cell / under the auspices of the European Cell Biology Organization》1996,88(3):123-129
Summary— As evidenced by pertussis toxin-catalysed [32P]ADP-ribosylation, immunoblotting and Northern blot, the human adenocarcinoma intestinal cell line Caco-2 expresses Gi2 and Gi3 proteins. The localization of these two Gis within the cell was investigated by using subcellular fractionation and confocal microscopy on intact cell layer. A brush-border rich fraction and a pellet containing the remaining cellular membranes were prepared. [32P]ADP-ribosylation and immunoblotting demonstrated the presence of both αi2 and αi3 in these two preparations. Immunofluorescence studies performed on intact cells grown on Transwell filters and viewed by confocal microscopy further confirmed the localization of αi3-subunit on basolateral as well as on apical membranes. In contrast, αi2-subunit was shown to accumulate mainly in the intra-cellular compartment while only faint staining of the plasma membrane was detectable. Based upon double-labelling experiments with antibody against rough endoplasmic reticulum (RER), there is a strong possibility that intra-cellular sites of αi2-subunit correspond to association with RER membranes. 相似文献