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301.
Carvedilol is an antihypertensive drug available as a racemic mixture. (?)‐(S)‐carvedilol is responsible for the nonselective β‐blocker activity but both enantiomers present similar activity on α1‐adrenergic receptor. To our knowledge, this is the first study of carvedilol enantiomers in human plasma using a chiral stationary phase column and liquid chromatography with tandem mass spectrometry. The method involves plasma extraction with diisopropyl ether using metoprolol as internal standard and direct separation of the carvedilol enantiomers on a Chirobiotic T® (Teicoplanin) column. Protonated ions [M + H]+ and their respective ion products were monitored at transitions of 407 > 100 for the carvedilol enantiomers and 268 > 116 for the internal standard. The quantification limit was 0.2 ng ml?1 for both enantiomers in plasma. The method was applied to study enantioselectivity in the pharmacokinetics of carvedilol administered as a single dose of 25 mg to a hypertensive patient. The results showed a higher plasma concentration of (+)‐(R)‐carvedilol (AUC0–∞ 205.52 vs. 82.61 (ng h) ml?1), with an enantiomer ratio of 2.48. Chirality, 2012. © 2012 Wiley Periodicals, Inc. 相似文献
302.
Mariángeles Briggiler Marcó Josiane E. Garneau Denise Tremblay Andrea Quiberoni Sylvain Moineau 《Applied and environmental microbiology》2012,78(24):8719-8734
We characterized two Lactobacillus plantarum virulent siphophages, ATCC 8014-B1 (B1) and ATCC 8014-B2 (B2), previously isolated from corn silage and anaerobic sewage sludge, respectively. Phage B2 infected two of the eight L. plantarum strains tested, while phage B1 infected three. Phage adsorption was highly variable depending on the strain used. Phage defense systems were found in at least two L. plantarum strains, LMG9211 and WCSF1. The linear double-stranded DNA genome of the pac-type phage B1 had 38,002 bp, a G+C content of 47.6%, and 60 open reading frames (ORFs). Surprisingly, the phage B1 genome has 97% identity with that of Pediococcus damnosus phage clP1 and 77% identity with that of L. plantarum phage JL-1; these phages were isolated from sewage and cucumber fermentation, respectively. The double-stranded DNA (dsDNA) genome of the cos-type phage B2 had 80,618 bp, a G+C content of 36.9%, and 127 ORFs with similarities to those of Bacillus and Lactobacillus strains as well as phages. Some phage B2 genes were similar to ORFs from L. plantarum phage LP65 of the Myoviridae family. Additionally, 6 tRNAs were found in the phage B2 genome. Protein analysis revealed 13 (phage B1) and 9 (phage B2) structural proteins. To our knowledge, this is the first report describing such high identity between phage genomes infecting different genera of lactic acid bacteria. 相似文献
303.
Josiane Seghieri Julie Carreau Nicolas Boulain Patricia De Rosnay Marc Arjounin Franck Timouk 《Plant Ecology》2012,213(5):861-870
Rainfall distribution and the soil moisture regime have been recognized to be the key drivers of the phenological rhythms
in Sahelian woody plants, although different climate triggers have been assumed to be involved in determining the date of
the onset of the phenophase. However, almost no comparisons have been made of the actual relative predictive power of these
environmental factors. The aim of our study was to quantify the ability of several factors to predict phenophase occurrence
in the dominant woody populations of northern Mali. Canopy leafing, flowering and fruiting were monitored from May 2005 to
July 2007. Multiple logistic regressions were used to test the predictive power of cumulative rainfall, soil moisture, air
temperature, air humidity and day length, with time lags of up to 2 months. Artificial variables derived from time lags observed
in phenophases were included as predictors to account for possible auto-correlation and cross-correlation among phenophases.
Surprisingly, a decrease in temperature associated with different time lags was most often found to be the strongest predictor
of both leafing and reproductive phenophases. In Sahelian shrubs, morphological and physiological adaptations strongly contribute
to the relative independence of their activity from water availability, leaf phenology being a way to adjust the plant water
balance to current water availability and atmospheric water content. This study provides insight towards the development of
a mechanistic understanding of phenological control in the Sahel, which is becoming increasingly important in the context
of expected climate changes. 相似文献
304.
Gwenola Auda-Boucher Thierry Rouaud Josiane Fontaine-Pérus Fabien Le Grand Marie-France Gardahaut 《The journal of histochemistry and cytochemistry》2003,51(10):1255-1267
We studied the behavior of myogenic progenitors from donor desmin(+/-) LacZ embryos after implantation into tibialis anterior muscle of 2-month-old mouse hosts. Myogenic progenitors were collected from 10-day post-coital mouse embryo somite dermomyotomes (DMs), forelimb buds (LBs), and trunks. The replacement of desmin by the LacZ coding sequence allowed specific monitoring of beta-galactosidase expression in donor myogenic cells. Immunostaining for myosin heavy chain and laminin expression was performed together with acetylcholine receptor histochemistry on sections of implanted muscle. Myogenic progenitors generated from DM, LB, and trunk were able to proliferate and adopt a myogenic pathway after transplantation into adult mouse muscle. Although their development appeared to be limited for DM and LB cell transplantation, the differentiation of myogenic progenitors occurred readily with trunk cell injection, suggesting that cell types associated with DM cells were involved in long-term myofiber differentiation (21 day). When neural tube/notochord (NTN) or sclerotomal (S) cells were co-transplanted with DM cells, myogenic nuclei were produced, indicating that both NTN and S are required for the differentiation of DMs grafted into adult muscle. These data are consistent with the differentiation of neural tissues and bone from NTN and S, respectively, and with the development of anatomic relations among all in vivo-differentiated tissues. These results suggest that embryonic trunk cells can be used to repair different types of injured tissues (especially skeletal muscle) under appropriate environmental conditions. 相似文献
305.
306.
Josiane Etang Lucien Manga Jean-Claude Toto Pierre Guillet Etienne Fondjo Fabrice Chandre 《Journal of vector ecology》2007,32(1):123-133
Some populations of Anopheles gambiae s.l. from Cameroon were reported to develop resistance to DDT or pyrethroids but were free of the kdr mutation "Leucine-Phenylalanine" (Leu-Phe). This study reports on the metabolic activity of non-specific esterases (NSEs), mixed function oxidases (MFOs), and glutathione S-transferases (GSTs), three enzyme systems commonly involved in insecticide resistance. Biochemical assays were performed in DDT or pyrethroid-resistant populations of An. gambiae s.l. from Douala, Mbalmayo, Pitoa, and Simatou neighborhoods. Enzyme activity was compared to the Kisumu-susceptible reference strain using the Mann-Whitney test. Most of the tested samples had elevated NSE activity (P < 0.02). The Douala sample evenly displayed elevated GST activity (P < 0.001), while high MFO level was recorded in the Pitoa sample (P < 0.001). MFO or GST levels were sometimes lower or similar to that of the Kisumu strain. These results suggest metabolic detoxification is a major DDT or pyrethroid resistance mechanism and emphasize the need for further investigations on An. gambiae s.l. resistance mechanisms in Cameroon. 相似文献
307.
Arnaud J Akbaraly TN Akbaraly NT Hininger I Roussel AM Berr C 《The Journal of nutritional biochemistry》2007,18(7):482-487
Selenium status decreases in elderly populations. Cardiovascular diseases are the primary cause of death in the French elderly, and selenium may protect against cardiovascular diseases. The present work aims to evaluate the relationships between cardiovascular-related risk factors and plasma selenium variability in an elderly population during a 9-year period. Seven hundred fifty-one subjects from the EVA ("Etude du Vieillissement Artériel") study, aged 59 to 71 at baseline, were followed for 9 years. Clinical examinations and lifestyle questionnaires were repeated every 2 years. Plasma selenium determinations were performed at baseline and at the end of the study. The association between the 9-year plasma selenium variability and studied risk factors at baseline or occurring during the follow-up was evaluated by using multivariate linear regression models. After controlling all potential associated factors, age of subjects (P<.01), obesity (P=.02) and occurrence of cardiovascular disease during follow-up (P=.03) increased the longitudinal decline in plasma selenium, whereas gender, education, smoking, alcohol intakes, dyslipidemia, diabetes, hypertension had no effect (P>.05). It may be postulated that obesity and occurrence of cardiovascular events are the main factors associated with plasma selenium fall during ageing. The respective roles played by nutritional and metabolism changes in the mechanism of these associations still need to be explored. 相似文献
308.
Eya1 and Eya2 proteins are required for hypaxial somitic myogenesis in the mouse embryo 总被引:3,自引:0,他引:3
Grifone R Demignon J Giordani J Niro C Souil E Bertin F Laclef C Xu PX Maire P 《Developmental biology》2007,302(2):602-616
309.
Tschamber T Gessier F Dubost E Newsome J Tarnus C Kohler J Neuburger M Streith J 《Bioorganic & medicinal chemistry》2003,11(17):3559-3568
The syntheses of four glyco-imidazoles, which are pentose-derivatives belonging to the D-series, as well as the syntheses of their L-enantiomers, are reported. Starting from the known linear xylo, lyxo, arabino, and ribo imidazolo-pentoses in both the L- and the D-series, intramolecular Walden inversion led to the corresponding arabino, ribo, xylo, and lyxo pyrrolidinopentoses in the D- and the L-series, respectively, protection and deprotection steps being unavoidable prerequisites. The structures and configurations of all eight pyrrolidinopentoses were determined unambiguously, by a combination of 1H/13C NMR spectroscopy, circular dichroism and [alpha](D) values, in conjunction with single-crystal X-ray diffraction analysis of the L-xylo stereoisomer. Examination of the inhibitory properties of these imidazolo-pyrrolidinoses against six commonly encountered glycosidases led to the conclusion that by and large the L-stereoisomers are inactive, whereas three out the four D-stereoisomers proved to be poor to moderate inhibitors. It appears therefore that the most basic N(1) atom is not located in an optimal topology to be protonated easily inside the enzyme's active site. 相似文献
310.
Alpha-fetoprotein controls female fertility and prenatal development of the gonadotropin-releasing hormone pathway through an antiestrogenic action 下载免费PDF全文
De Mees C Laes JF Bakker J Smitz J Hennuy B Van Vooren P Gabant P Szpirer J Szpirer C 《Molecular and cellular biology》2006,26(5):2012-2018
It has been shown previously that female mice homozygous for an alpha-fetoprotein (AFP) null allele are sterile as a result of anovulation, probably due to a defect in the hypothalamic-pituitary axis. Here we show that these female mice exhibit specific anomalies in the expression of numerous genes in the pituitary, including genes involved in the gonadotropin-releasing hormone pathway, which are underexpressed. In the hypothalamus, the gonadotropin-releasing hormone gene, Gnrh1, was also found to be down-regulated. However, pituitary gene expression could be normalized and fertility could be rescued by blocking prenatal estrogen synthesis using an aromatase inhibitor. These results show that AFP protects the developing female brain from the adverse effects of prenatal estrogen exposure and clarify a long-running debate on the role of this fetal protein in brain sexual differentiation. 相似文献