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61.
Analysis of four microsatellite markers on the long arm of chromosome 9 by meiotic recombination in flow-sorted single sperm. 总被引:1,自引:1,他引:0 下载免费PDF全文
R A Furlong D R Goudie N P Carter J E Lyall N A Affara M A Ferguson-Smith 《American journal of human genetics》1993,52(6):1191-1199
Meiotic recombination in flow-sorted single sperm was used to analyze four highly polymorphic microsatellite markers on the long arm of chromosome 9. The microsatellites comprised three tightly linked markers: 9CMP1 (D9S109), 9CMP2 (D9S127), and D9S53, which map to 9q31, and a reference marker, ASS, which is located in 9q34.1. Haplotypes of single sperm were assessed by using PCR in a single-step multiplex reaction to amplify each locus. Recombinant haplotypes were identified by their relative infrequency and were analyzed using THREELOC, a maximum-likelihood-analysis program, and an adaptation of CRI-MAP. The most likely order of these markers was cen-D9S109-D9S127-D9S53-ASS-tel with D9S109, D9S127, and D9S53 being separated by a genetic distance of approximately 3%. The order of the latter three markers did not however achieve statistical significance using the THREELOC program. 相似文献
62.
63.
Loren H. Rieseberg Ronald Carter Scott Zona 《Evolution; international journal of organic evolution》1990,44(6):1498-1511
Enzyme electrophoresis and restriction-fragment analysis of chloroplast DNA (cpDNA) and nuclear ribosomal DNA (rDNA) were used to test the hypothesis that both Helianthus neglectus and H. paradoxus are stabilized hybrid derivatives of H. annuus and H. petiolaris. The four species are annuals, diploid outcrossers, and have the same chromosome number. Helianthus annuus and H. petiolaris had the same allele in highest frequency for 16 of the 18 isozyme loci examined and had different majority alleles for only 6-Pgd3 and Pgi2. The two species had divergent rDNAs that could be distinguished by seven diagnostic restriction site mutations and three length mutations, and their cpDNAs could be differentiated by three diagnostic restriction site mutations. The alleles observed in H. neglectus were not a combination of those observed in H. annuus and H. petiolaris. Although H. neglectus had only one unique allele, it possessed none of the three alleles specific to H. annuus. In contrast, it had four of the seven alleles specific to H. petiolaris. Furthermore, H. neglectus had the same rDNA type as H. petiolaris and had the same cpDNA as that found in two populations of H. petiolaris ssp. fallax. These data allowed us to speculate that H. neglectus may be a recent derivative of H. petiolaris ssp. fallax, rather than a stabilized hybrid derivative as originally proposed. In contrast, H. paradoxus combined the alleles of H. annuus and H. petiolaris and had no unique alleles. At Adh2, H. paradoxus was monomorphic for an allele found only in H. petiolaris ssp. fallax, whereas at 6-Pgd3 and Pgi2, it was monomorphic for high frequency H. annuus alleles. Furthermore, H. paradoxus combined the rDNA repeat types of both proposed parents and had the chloroplast genome of H. annuus. These data provide compelling evidence that H. paradoxus, in contrast to H. neglectus, was derived via hybridization. 相似文献
64.
This is the report of a meeting held in Ahungalla, Sri Lanka, 16-19 January 1994, under the sponsorship of the Rockefeller Foundation, Health Sciences Division. The meeting was initiated jointly by the Rockefeller Foundation and the TDR Special Programme of the World Health Organization in order to bring together scientists with a wide spectrum of experience relating to malarial disease and pathogenesis. The objective was to generate interdisciplinary discussion ranging from the clinical pictures of malarial infections and their impact in different parts of the world, to current investigations on mechanisms of pathogenesis and clinical immunity and the genetic determinants in human and parasite populations affecting the nature of the disease. 相似文献
65.
Cyclophilin A-induced alterations of human immunodeficiency virus type 1 CA protein in vitro. 总被引:3,自引:2,他引:1 下载免费PDF全文
Cyclophilin A (CyP A), a cellular chaperone with cis-trans prolyl isomerase activity, is required for postassembly events in human immunodeficiency virus type 1 (HIV-1) replication. The requirement for CyP A maps to sequences in the capsid (CA) domain of the structural precursor, Gag. To determine the effects of interaction with CyP A on capsid (CA) protein structure, the binding interaction was investigated in vitro, using recombinant HIV-1 CA protein (which forms oligomers in solution) and human CyP A. The CA and CyP A proteins interacted to form a complex which was detected predominantly as a heterodimer on sodium dodecyl sulfate (SDS)-polyacrylamide gels. Complex formation exhibited a pH optimum of 5. The CA protein in the complex was exclusively in a conformation whereby the N terminus was blocked to Edman degradation. This finding was unexpected since CyP A binds to the central region of the CA protein (residues 85 to 93). Examination of CA protein incubated with CyP A for alterations in structure indicated that CyP A preferentially interacted with the subpopulation of trypsin-susceptible subunits in the oligomers and significantly reduced their sensitivity to proteolysis. Like CA-CyP A complex formation, conversion to trypsin resistance also exhibited a pH optimum of 5. Both complex formation and the changes in tryptic susceptibility were only partially inhibited by cyclosporin A (CsA). This appeared to be due to a CA subpopulation able to bind CyP A despite the presence of CsA. Our results identify specific tryptic sites both proximal and distal to the CyP A binding region that are altered by CyP A binding and/or by CyP A's prolyl isomerase activity. Comparison with the X-ray structure of a complex containing CyP A bound to an amino-terminal fragment of the CA protein (CA1-151) (T.R. Gamble et al., Cell 87:1285-1294, 1996) indicates that the tryptic sites that become inaccessible are among the same residues that lose a significant amount of accessible surface area through CA-CA subunit contacts made in the presence of CyP A. 相似文献
66.
Development of a Robust Flow Cytometric Assay for Determining Numbers of Viable Bacteria 总被引:9,自引:3,他引:6 下载免费PDF全文
R. I. Jepras J. Carter S. C. Pearson F. E. Paul M. J. Wilkinson 《Applied microbiology》1995,61(7):2696-2701
Several fluorescent probes were evaluated as indicators of bacterial viability by flow cytometry. The probes monitor a number of biological factors that are altered during loss of viability. The factors include alterations in membrane permeability, monitored by using fluorogenic substrates and fluorescent intercalating dyes such as propidium iodide, and changes in membrane potential, monitored by using fluorescent cationic and anionic potential-sensitive probes. Of the fluorescent reagents examined, the fluorescent anionic membrane potential probe bis-(1,3-dibutylbarbituric acid)trimethine oxonol [DiBAC(inf4)(3)] proved the best candidate for use as a general robust viability marker and is a promising choice for use in high-throughput assays. With this probe, live and dead cells within a population can be identified and counted 10 min after sampling. There was a close correlation between viable counts determined by flow cytometry and by standard CFU assays for samples of untreated cells. The results indicate that flow cytometry is a sensitive analytical technique that can rapidly monitor physiological changes of individual microorganisms as a result of external perturbations. The membrane potential probe DiBAC(inf4)(3) provided a robust flow cytometric indicator for bacterial cell viability. 相似文献
67.
Baker R. L. Cox E. H. Carter A. H. 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1984,67(2-3):113-122
Summary Four lines of mice were formed from a common base population and selected for 37 generations for either increased 3-week weight (weaning weight), 6-week weight, 3–6 week gain, or maintained as a randomly bred control line. Realised heritability estimates for short-term (long-term) responses were 0.33±0.20 (0.07±0.10), 0.46±0.14 (0.26±0.09), 0.36±0.14 (0.24±0.11) for 3-week weight, 6-week weight and 3–6 week gain, respectively. Realised genetic correlations estimated from short-term (long-term) responses were 0.23±0.08 (0.35±0.10) between 3-week weight and 3–6 week gain; 0.82±0.04 (0.58±0.08) between 3-week weight and 6-week weight; and 0.81±0.04 (0.97±0.04) between 3–6 week gain and 6-week weight. The genetic correlation between 3-week weight and 6-week weight was asymmetric with a greater correlated response for 3-week weight when selecting for 6-week weight (1.06) than vice versa (0.63). 相似文献
68.
A M Carter 《Journal of developmental physiology》1984,6(5):407-416
Guinea-pigs near term of pregnancy were anaesthetized with diazepam and sodium pentobarbitone. A fetus was exposed and the vitelline artery catheterized to measure blood pressure and heart rate or to render a reference sample of blood for the determination of organ blood flow by the microsphere technique. The radioactive microspheres were injected through a catheter in the right atrium. Mean arterial blood pressure was 4.0 kPa and heart rate was 261 beats min-1. The liver, spleen, pancreas and gut receive most of their blood supply from the same trunk as the vitelline artery. The sample from this vessel was also used to calculate blood flow to the adrenal glands, kidneys, urogenital tract, and placenta, assuming even mixing of microspheres and blood in the abdominal aorta. Umbilical blood flow, corrected to a fetal weight of 100 g, averaged 7.5 ml min-1. The adrenal glands, which are known to increase their cortisol secretion near term, had a very high rate of perfusion. If the microspheres were injected in the umbilical vein, almost all were trapped in the liver, confirming the absence of a ductus venosus in the guinea-pig fetus. Most of these microspheres were found in the quadrate lobe of the liver. Hepatic arterial blood flow was also unequally distributed, with more than two-thirds going to the right lobe of the liver. Although the distribution of portal venous blood flow is not known, it is evident that different areas of the liver are presented with blood of greatly varying oxygen saturation. 相似文献
69.
R.Douglas Carter Robert E. Hardy Kilian Dill 《International journal of biological macromolecules》1984,6(3):164-166
The 13C resonances of Nα,N-[13C]dimethylserine of partially 13C reductively methylated glycophorin AM were monitored as a function of pH at 45°C. For comparison, limited data are also presented for the pH dependence of the 13C resonances of Nα,N- [13C]dimethylserine of fully 13C reductively methylated deglycosylated glycophorin AM. The ‘major’ component of Nα,N- [13C]dimethylserine of glycophorin AM did not titrate, whereas the ‘minor’ component titrated with a pKa of 7.80 (Hill coefficient of 0.95). Similar results are also indicated for the Nα,N- [13C]dimethylserine resonances of 13C reductively methylated deglycosylated glycophorin AM. 相似文献
70.
J. P. Monson R. M. Henderson J. A. Smith R. A. Iles M. Faus-Dader N. D. Carter R. Heath H. Metcalfe R. D. Cohen 《Bioscience reports》1984,4(10):819-825
In perfused rat liver a decrease of cytosol pH, determined with pH-sensitive microelectrodes7 from 7.2 to 6.85 is associated with a 50% fall in ureogenesis from ammonium chloride. In isolated rat hepatocytes the fall in ureogenesis due to acidosis is associated with decrease in the mitochondrial and cytosolic concentration of citrulline. Limitation of carbamoyl phosphate synthesis and thus citrulline supply could be responsible for the inhibition of ureogenesis observed. 相似文献