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991.
Peter T. Katzmarzyk William R. Leonard Merrill A. Stephen Peter R. Berti Allen G. P. Ross 《American journal of physical anthropology》1996,99(4):537-545
Estimates of daily energy expenditure are important for many areas of research in human ecology and adaptability. The most common technique for estimating human energy expenditure under field conditions, the factorial method, generally relies on activity-specific energy costs derived from published sources, based largely on North American and European subjects. There is concern that such data may not be appropriate for non-Western populations because of differences in metabolic costs. The present study addresses this concern by comparing measured vs. predicted energy costs at rest and during sub-maximal exercise in 83 subjects (52 males, 31 females) from three subsistence-level populations (Siberian herders and high-land and coastal Ecuadorian farmers). Energy costs at rest (i.e., lying, sitting and standing) and while performing a standard stepping exercise did not significantly differ among the three groups. However, resting energy costs were significantly elevated over predicted levels (+16% in men, +11% in women), whereas exercising costs were comparable to predicted values (?6% in men, +3% in women). Elevations in resting energy needs appear to reflect responses to thermal stress. These results indicate that temperature adjustments of resting energy costs are critical for accurately predicting daily energy needs among traditionally living populations. o 1996 Wiley-Liss, Inc. 相似文献
992.
Comparison of Vero cell assay and PCR as indicators of the presence of verocytotoxigenic Escherichia coli in bovine and human fecal samples. 总被引:1,自引:0,他引:1 下载免费PDF全文
K Rahn J B Wilson K A McFadden S C Read A G Ellis S A Renwick R C Clarke R P Johnson 《Applied microbiology》1996,62(12):4314-4317
Comparisons were made between Vero cell assay (VCA) and PCR as indicators for the detection of verocytotoxigenic Escherichia coli (VTEC; also known as Shiga-like toxin-producing E. coli) and as predictors of VTEC isolation from bovine and human fecal samples. Fecal samples were collected as part of a survey on the prevalence of VTEC on dairy farms in southern Ontario (J. B. Wilson et al., J. Infect. Dis., 174:1021-1027, 1996). A total of 2,655 samples were examined by VCA and PCR, 2,153 originating from cattle and 502 originating from humans. Overall, 36.2% of the samples were positive in the VCA and 38.7% were positive by PCR. Of the VCA-positive samples screened, 41.6% yielded a VTEC isolate. For both human and bovine samples, a significant positive association between PCR result and VCA titer (P = 0.0001) was found. In addition, there was a significant positive association between the PCR result and VTEC isolation from VCA-positive samples for cattle (odds ratio = 9.1, P < 0.0001). For bovine samples positive in the VCA, VCA titer was significantly associated with the probability of obtaining a VTEC isolate. Agreement between VCA and PCR was good for both bovine and human samples (kappa = 0.69 and 0.64, respectively). The sensitivity and specificity of the PCR with respect to the VCA for bovine samples were 82.0 and 86.5%, respectively, and those for human samples were 59.3 and 98.1%, respectively. Although correlation between VCA and PCR results was not absolute, when used in conjunction, these tests complemented one another as predictors of VTEC isolation. 相似文献
993.
Confirmational identification of Escherichia coli, a comparison of genotypic and phenotypic assays for glutamate decarboxylase and beta-D-glucuronidase. 下载免费PDF全文
A E McDaniels E W Rice A L Reyes C H Johnson R A Haugland G N Stelma Jr 《Applied microbiology》1996,62(9):3350-3354
Genotypic and phenotypic assays for glutamate decarboxylase (GAD) and beta-D-glucuronidase (GUD) were compared for their abilities to detect various strains of Escherichia coli and to discriminate among other bacterial species. Test strains included nonpathogenic E. coli, three major groups of diarrheagenic E. coli, three other non-coli Escherichia species, and various other gram-negative and -positive bacteria found in water. The genotypic assays were performed with hybridization probes generated by PCR amplification of 670- and 623-bp segments of the gadA/B (GAD) and uidA (GUD) genes, respectively. The GAD enzymes catalyze the alpha-decarboxylation of L-glutamic acid to yield gamma-aminobutyric acid and carbon dioxide, which are detected in the phenotypic assay by a pH-sensitive indicator dye. The phenotypic assay for GUD involves the transformation of 4-methylumbelliferyl-beta-D-glucuronide to the fluorogenic compound 4-methylumbelliferone. The GAD phenotypic assay detected the majority of the E. coli strains tested, whereas a number of these strains, including all representatives of the O157:H7 serotype and several nonpathogenic E. coli strains, gave negative results in the GUD assay. Both phenotypic assays detected some but not all strains from each of the four Shigella species. A strain of Citrobacter freundii was also detected by the GUD assay but not by the GAD assay. All E. coli and Shigella strains were detected with both the gadA/B and uidA probes. A few Escherichia fergusonii strains gave weak hybridization signals in response to both probes at 65 degrees C but not at 68 degrees C. None of the other bacterial species tested were detected by either probe. These results were consistent with previous reports which have indicated that the GAD phenotypic assay detects a wider range of E. coli strains than does the GUD assay and is also somewhat more specific for this species. The genotypic assays for the two enzymes were found to be equivalent in both of these respects and superior to both of the phenotypic assays in terms of the range of E. coli strains and isolates detected. 相似文献
994.
995.
Tama Hasson Joseph F. Skowron Debra J. Gilbert Karen B. Avraham William L. Perry William M. Bement Blake L. Anderson Elliott H. Sherr Zheng-Yi Chen Lloyd A. Greene David C. Ward David P. Corey Mark S. Mooseker Neal G. Copeland Nancy A. Jenkins 《Genomics》1996,36(3):431
Myosins are molecular motors that move along filamentous actin. Seven classes of myosin are expressed in vertebrates: conventional myosin, or myosin-II, as well as the 6 unconventional myosin classes -I, -V, -VI, -VII, -IX, and -X. We have mapped in mouse 22 probes encompassing all known unconventional myosins and, as a result, have identified 16 potential unconventional myosin genes. These genes include 7 myosins-I, 2 myosins-V, 1 myosin-VI, 3 myosins-VII, 2 myosins-IX, and 1 myosin-X. The map location of 5 of these genes was identified in human chromosomes by fluorescencein situhybridization. 相似文献
996.
997.
Identification of molecular markers in soybean comparing RFLP,RAPD and AFLP DNA mapping techniques 总被引:16,自引:0,他引:16
Jhy-Jhu Lin Jonathan Kuo Jin Ma James A. Saunders Hunter S. Beard Margaret H. MacDonald William Kenworthy George N. Ude Benjamin F. Matthews 《Plant Molecular Biology Reporter》1996,14(2):156-169
Three different DNA mapping techniques—RFLP, RAPD and AFLP—were used on identical soybean germplasm to compare their ability
to identify markers in the development of a genetic linkage map. Polymorphisms present in fourteen different soybean cultivars
were demonstrated using all three techniques. AFLP, a novel PCR-based technique, was able to identify multiple polymorphic
bands in a denaturing gel using 60 of 64 primer pairs tested. AFLP relies on primers designed in part on sequences for endonuclease
restriction sites and on three selective nucleotides. The 60 diagnostic primer pairs tested for AFLP analysis each distinguished
on average six polymorphic bands. Using specific primers designed for soybean fromEco RI andMse I restriction site sequences and three selective nucleotides, as many as 12 polymorphic bands per primer could be obtained
with AFLP techniques. Only 35% of the RAPD reactions identified a polymorphic band using the same soybean cultivars, and in
those positive reactions, typically only one or two polymorphic bands per gel were found. Identification of polymorphic bands
using RFLP techniques was the most cumbersome, because Southern blotting and probe hybridization were required. Over 50% of
the soybean RFLP probes examined failed to distinguish even a single polymorphic band, and the RFLP probes that did distinguish
polymorphic bands seldom identified more than one polymorphic band. We conclude that, among the three techniques tested, AFLP
is the most useful. 相似文献
998.
999.
1000.
Gavin R. Sills William Bridges Salah M. Al-Janabi Bruno W. S. Sobral 《Molecular breeding : new strategies in plant improvement》1995,1(4):355-363
Saccharum robustum Brandes & Jesw. ex Grassl has been suggested as the immediate progenitor species of cultivated sugarcane (S. officinarum L.) [4]. Chromosome pairing and assortment in these two species were previously studied by genetic analysis of single-dose DNA markers in parents in and 44 F1 progeny of a cross between euploid, meiotically regular 2n=80S. officinarum LA Purple andS. robustum Mol 5829 [2]. This same population was subsequently clonally propagated and evaluated in replicated trials for quantitative traits important to sugarcane breeders. Numbers of stalks, tasseled stalks, and stalks with smut, and the average diameter of two stalks were determined one day prior to harvest. At harvest, plant material from each plot was weighed and evaluated for pol (sucrose content) and fiber percentages. Clones were significantly different (P<0.01) for all traits analyzed. Associations of 83 single-dose arbitrarily primed PCR genetic markers with quantitative trait loci (QTL) of recorded traits was determined by single-factor ANOVA, and multiple regression. QTL analysis revealed markers significantly (P<0.05) associated with the expression of each trait analyzed. Markers associated with QTL after multiple regression were tested for digenic linear × linear epistatic interactions. The various multilocus models explained between 23% and 58% of the total phenotypic variation and 32% and 76% of the genotypic variation for the various traits. Digenic interactions were uncommon. Implications for marker-assisted selection in sugarcane and sugarcane domestication are discussed. 相似文献