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71.
Influence of time of mating and paced copulation on induction of pseudopregnancy in cyclic female rats 总被引:5,自引:0,他引:5
The present experiment was designed to examine whether changes occur during the course of behavioural oestrus in the sensitivity of the female to copulatory stimulation and in patterns of sexual behaviour which might influence the likelihood of luteal maintenance. Cyclic female rats were mated on the evening of pro-oestrus (21:00 h) or early on the morning of oestrus (05:00 h) and received either 5 or 10 intromissions from males under conditions which allowed or did not allow pacing of contacts with males to occur. During mating, the levels of sexual receptivity, the timing of sexual mounts from males, and pacing behaviours were measured. The occurrence of pseudopregnancy or pregnancy in each animal was determined by examining vaginal smears for 14 days after mating and by examining the uterus for the presence of fetuses at the end of the experiment. At both mating times, pacing of copulation with males increased the likelihood of prolonged luteal activity. However, females were more likely to become pseudopregnant following non-paced mating at 05:00 h than at 21:00 h the previous evening. Of those females receiving an ejaculation during mating, no difference were seen between groups in the incidence of pregnancy. This change in sensitivity to cervical-vaginal stimulation during oestrus was not associated with changes in sexual receptivity or pacing behaviour. The ability of cervical-vaginal stimulation to induce pseudopregnancy therefore increases toward the end of the period of oestrus, but the behavioural mechanisms which regulate receipt of such stimulation remain constant during that time. 相似文献
72.
Reginald F. Frye Dwight D. Stiff 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1996,686(2):5281
A sensitive and reproducible method is described for the determination of the cytochrome P450 enzyme 2E1 substrate chlorzoxazone and its primary metabolite 6-hydroxychlorzoxazone in human plasma and urine. Plasma or diluted urine were acidified, incubated with β-glucuronidase and then were extracted with diethyl ether. Separation of the analytes was achieved on a C18 column with UV detection set at 283 nm. Excellent linearity was observed over the concentration ranges of 100–3000 ng/ml and 4–400 μg/ml in plasma and urine, respectively. The intra-assay variability was 5.1% and the inter-assay variability was 8.2% for each compound in each matrix. The method presented is applicable to pharmacokinetic and pharmacogenetic studies utilizing chlorzoxazone. 相似文献
73.
Evolution of eutherian cytochrome c oxidase subunit II: heterogeneous rates of protein evolution and altered interaction with cytochrome c 总被引:3,自引:1,他引:2
Cytochrome c oxidase subunit II (COII), encoded by the mitochondrial
genome, exhibits one of the most heterogeneous rates of amino acid
replacement among placental mammals. Moreover, it has been demonstrated
that cytochrome c oxidase has undergone a structural change in higher
primates which has altered its physical interaction with cytochrome c. We
collected a large data set of COII sequences from several orders of mammals
with emphasis on primates, rodents, and artiodactyls. Using phylogenetic
hypotheses based on data independent of the COII gene, we demonstrated that
an increased number of amino acid replacements are concentrated among
higher primates. Incorporating approximate divergence dates derived from
the fossil record, we find that most of the change occurred independently
along the New World monkey lineage and in a rapid burst before apes and Old
World monkeys diverged. There is some evidence that Old World monkeys have
undergone a faster rate of nonsynonymous substitution than have apes. Rates
of substitution at four-fold degenerate sites in primates are relatively
homogeneous, indicating that the rate heterogeneity is restricted to
nondegenerate sites. Excluding the rate acceleration mentioned above,
primates, rodents, and artiodactyls have remarkably similar nonsynonymous
replacement rates. A different pattern is observed for transversions at
four-fold degenerate sites, for which rodents exhibit a higher rate of
replacement than do primates and artiodactyls. Finally, we hypothesize
specific amino acid replacements which may account for much of the
structural difference in cytochrome c oxidase between higher primates and
other mammals.
相似文献
74.
An outbreak of blastomycosis in Eastern Tennessee 总被引:1,自引:1,他引:0
Most cases of blastomycosis are sporadic and only nine outbreaks representing a total of 112 cases have previously been reported. Less than half of these have been culture proven cases. Outbreaks have previously occurred in North Carolina, Minnesota, Illinois, Wisconsin and Virginia. We report three culturally confirmed cases of blastomycosis from Elizabethton, Tennessee, who had onset of illness within a one-week span of time. The patients presented with fever, chest pain, weight loss, poor appetite and myalgia. Each initially had a dry cough which became productive of purulent sputum as the illness progressed. Mild hemoptysis occurred during each patient's course. Serologic testing by immunodiffusion and enzyme immunoassay were positive and testing by complement fixation was negative in each case. The diagnosis was made by histopathology on transbronchial biopsy or transthoracic needle aspiration material. Each patient improved on ketoconazole therapy. 相似文献
75.
Paired sequence difference in ribosomal RNAs: evolutionary and phylogenetic implications 总被引:12,自引:1,他引:11
Ribosomal RNAs have secondary structures that are maintained by internal
Watson-Crick pairing. Through analysis of chordate, arthropod, and plant 5S
ribosomal RNA sequences, we show that Darwinian selection operates on these
nucleotide sequences to maintain functionally important secondary
structure. Insect phylogenies based on nucleotide positions involved in
pairing and the production of secondary structure are incongruent with
those constructed on the basis of positions that are not. Furthermore,
phylogeny reconstruction using these nonpairing bases is concordant with
other, morphological data.
相似文献
76.
Felipe A. de Oliveira Mohamed H. Shahin Yan Gong Caitrin W. McDonough Amber L. Beitelshees John G. Gums Arlene B. Chapman Eric Boerwinkle Stephen T. Turner Reginald F. Frye Oliver Fiehn Rima Kaddurah-Daouk Julie A. Johnson Rhonda M. Cooper-DeHoff 《Metabolomics : Official journal of the Metabolomic Society》2016,12(8):129
Introduction
While atenolol is an effective antihypertensive agent, its use is also associated with adverse events including hyperglycemia and incident diabetes that may offset the benefits of blood pressure lowering. By combining metabolomic and genomic data acquired from hypertensive individuals treated with atenolol, it may be possible to better understand the pathways that most impact the development of an adverse glycemic state.Objective
To identify biomarkers that can help predict susceptibility to blood glucose excursions during exposure to atenolol.Methods
Plasma samples acquired from 234 Caucasian participants treated with atenolol in the Pharmacogenomic Evaluation of Antihypertensive Responses trial were analyzed by gas chromatography Time-Of-Flight Mass Spectroscopy. Metabolomics and genomics data were integrated by first correlating participant’s metabolomic profiles to change in glucose after treatment with atenolol, and then incorporating genotype information from genes involved in metabolite pathways associated with glucose response.Results
Our findings indicate that the baseline level of β-alanine was associated with glucose change after treatment with atenolol (Q = 0.007, β = 2.97 mg/dL). Analysis of genomic data revealed that carriers of the G allele for SNP rs2669429 in gene DPYS, which codes for dihydropyrimidinase, an enzyme involved in β-alanine formation, had significantly higher glucose levels after treatment with atenolol when compared with non-carriers (Q = 0.05, β = 2.76 mg/dL). This finding was replicated in participants who received atenolol as an add-on therapy (P = 0.04, β = 1.86 mg/dL).Conclusion
These results suggest that β-alanine and rs2669429 may be predictors of atenolol-induced hyperglycemia in Caucasian individuals and further investigation is warranted.77.
Hruska MW Frye RF 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2004,803(2):317-320
Rosiglitazone is a thiazolidinedione antihyperglycemic drug used in the treatment of type 2 diabetes mellitus. Rosiglitazone is extensively metabolized by cytochrome P450 2C8 and so may have some utility as an in vivo probe for this enzyme. A liquid chromatographic method using sensitive fluorescence detection and simplified sample processing involving protein precipitation with acetonitrile was developed. The isocratic mobile phase consisted of 10 mM sodium acetate-acetonitrile (pH 5; 60:40, v/v) and was delivered at a flow rate of 1 ml/min to an Alltima phenyl column (250 mm x 4.6 mm, 5 microm). Detection was by fluorescence at (EX/EM) 247/367 for rosiglitazone and 235/310 for the internal standard betaxolol. Intra- and inter-day precision ranged from 3.1 to 8.5% and 2.3 to 5.7%, respectively. No endogenous interference was observed with either rosiglitazone or the internal standard. The assay is simple, economical, precise, and is directly applicable to human pharmacokinetic studies involving single dose rosiglitazone administration. 相似文献
78.
R A Frye 《Biochemical and biophysical research communications》1999,260(1):273-279
The yeast Sir2 protein regulates epigenetic gene silencing and as a possible antiaging effect it suppresses recombination of rDNA. Studies involving cobB, a bacterial SIR2-like gene, have suggested it could encode a pyridine nucleotide transferase. Here five human sirtuin cDNAs are characterized. The SIRT1 sequence has the closest homology to the S. cerevisiae Sir2p. The SIRT4 and SIRT5 sirtuins more closely resemble prokaryotic sirtuin sequences. The five human sirtuins are widely expressed in fetal and adult tissues. Recombinant E. coli cobT and cobB proteins each showed a weak NAD-dependent mono-ADP-ribosyltransferase activity using 5, 6-dimethylbenzimidazole as a substrate. Recombinant E. coli cobB and human SIRT2 sirtuin proteins were able to cause radioactivity to be transferred from [32P]NAD to bovine serum albumin (BSA). When a conserved histidine within the human SIRT2 sirtuin was converted to a tyrosine, the mutant recombinant protein was unable to transfer radioactivity from [32P]NAD to BSA. These results suggest that the sirtuins may function via mono-ADP-ribosylation of proteins. 相似文献
79.
80.