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121.
122.
Cassone M Campanile F Pantosti A Venditti M Stefani S 《Microbial drug resistance (Larchmont, N.Y.)》2004,10(1):43-49
We describe the identification of a variant of the "Rome clone" of methicillin-resistant Staphylococcus aureus (MRSA), responsible for an outbreak involving 5 patients in a Cardiac Surgery Intensive Care Unit (CS-ICU) of a tertiary-care University Hospital in Rome. All strains isolated from patients and from nasal swabs obtained from four members of the CS-ICU personnel, belonged to the same identified clone. The characteristics of this clone were: (1) resistance to ampicillin, oxacillin, gentamicin, ciprofloxacin, erythromycin, clindamycin, rifampin, spectinomycin, and tetracycline; (2) vancomycin and teicoplanin MICs respectively of 2 and 4 mg/L; (3) heteroresistant subpopulations in the presence of 4 and 6 mg/L of vancomycin (10(-3) and 10(-5), respectively); (4) clonal type I::J::C determined following an established protocol (mec A::Tn 554 ::PFGE); (5) sequence type ST247 (3-3-1-12-4-4-16), obtained by multilocus sequence typing (MLST); and (6) the staphylococcal cassette chromosome mec (SCC) IA, obtained by multiplex PCR method. This new strain had different characteristics from the epidemic clone circulating in the same hospital from 1997 and designed "Rome clone," which was susceptible to erythromycin, clindamycin, and spectinomycin and belonged to the II::NH::C genetic background. A high genetic similarity between this Rome clone and the previously classified Archaic and Iberian clones was found, because they shared the same allelic profile (ST247), probably originating from the same S. aureus ancestor of the Iberian MRSA strains. Therefore, the strains responsible for the outbreak, with vancomycin MICs 2-4 mg/L, are variant clones, showing the genotype of the "Rome clone," the ST247 in association with SCC mec type IA (ST247-MRSA-IA), and are characterized by a uniform susceptibility to fosfomycin. 相似文献
123.
124.
Developmental changes in calcium dynamics, protein kinase C distribution and endoplasmic reticulum organization in human preimplantation embryos 总被引:2,自引:2,他引:2
Developmental changes in the Ca2+ dynamics of human zygotesand preimplantation embryos were related to changes in the distributionof endoplasmic reticulum (ER) and protein kinase C (PKC). Thefertilization-induced Ca2+ oscillations were typically observedover >5 h, were ryanodine-sensitive and showed a periphery-to-centrepropagation of Ca2+ waves. At the same time, ER and PKC wereaccumulated in the cell periphery. After the appearance of pronuclei,ryanodine-sensitive Ca2+ oscillations of lower amplitude andfrequency were observed until the pronuclear breakdown. However,Ca2+ waves then began in the perinuclear region, in the areaof ER and PKC accumulation and spread towards the cell periphery.During the second to fourth cell cycle, small sinusoidal Ca2+fluctuations were observed; sparse higher-amplitude Ca2+ spikes,superimposed on these basal fluctuations, appeared shortly beforecell division. The sinusoidal Ca2+ fluctuations were asynchronousin individual blastomeres and disappeared progressively in arrestedembryos. The direction of Ca2+ wave propagation and the distributionof ER and PKC were similar to the situation observed in pronuclearzygotes. In contrast to the zygotes, ryanodine did not arrestthe Ca2+ oscillations but augmented their amplitude and frequency.These data suggest that human pre-embryos use different mechanismsof Ca2+ signalling in the early post-fertilization period, duringthe pronuclear development and during cleavage. calcium dynamics/endoplasmic reticulum/human preimplantation embryos/protein kinase C/ryanodine 相似文献
125.
Surface properties and cell response of low metal ion release Ti-6Al-7Nb alloy after multi-step chemical and thermal treatments 总被引:5,自引:0,他引:5
Ti-6Al-7Nb samples treated by innovative multi-step chemical and thermal processes were characterized in order to evaluate their surface properties and cell interaction. The main object was to asses if the treatments were effective in order to obtain a surface presenting at the same time bone-like apatite induction ability, low metal ion release, good cell response and high protein binding. The morphology, crystallographic structure, porosity and wettability of the treated materials were investigated, as well as their interaction with simulated body fluid during soaking for different times. Cytotoxicity, protein adsorption tests and in vitro fibroblast and osteoblast-like cell cultures were also performed. 相似文献
126.
Juan Bartulín Bernab Luis Rivas Mario Rodríguez-Baeza Ursula Angne 《Macromolecular chemistry and physics.》1982,183(12):2935-2940
Linear poly(iminoethylene) was synthetised by cationic polymerization of 2-methyl-2-oxazoline using BF3? O(C2H5)2, SnCl4, and CH3COBF4 as initiators and in the presence or absence of CH3CN. The resulting product, poly(N-acetyliminoethylene), was then hydrolysed in basic medium. The resulting poly(iminoethylene) was identified and characterized by 1H NMR, 13C NMR, X-ray diffraction, and differential scanning calorimetry (DSC). The synthetised polymer will be used as a polymeric support in ionic-exchange resins as well as in macromolecular pesticides. 相似文献
127.
Enrico M Trecarichi Mario Tumbarello de Gaetano Katleen Donati Enrica Tamburrini Roberto Cauda Christina Brahe Francesco D Tiziano 《AIDS research and therapy》2006,3(1):22-4
Despite multiple sexual exposure to HIV-1 virus, some individuals remain HIV-1 seronegative (exposed seronegative, ESN). The
mechanisms underlying this resistance remain still unclear, although a multifactorial pathogenesis can be hypothesised. Although
several genetic factors have been related to HIV-1 resistance, the homozigosity for a mutation in CCR5 gene (the 32 bp deletion, i.e. CCR5-Delta32 allele) is presently considered the most relevant one. In the present study we
analysed the genotype at CCR5 locus of 30 Italian ESN individuals (case group) who referred multiple unprotected heterosexual intercourse with HIV-1 seropositive
partner(s), for at least two years. One hundred and twenty HIV-1 infected patients and 120 individuals representative of the
general population were included as control groups. Twenty percent of ESN individuals had heterozygous CCR5-Delta 32 genotype,
compared to 7.5% of HIV-1 seropositive and 10% of individuals from the general population, respectively. None of the analysed
individuals had CCR5-Delta 32 homozygous genotype. Sequence analysis of the entire open reading frame of CCR5 was performed in all ESN subjects and no polymorphisms or mutations were identified. Moreover, we determined the distribution
of C77G variant in CD45 gene, which has been previously related to HIV-1 infection susceptibility. The frequency of the C77G
variant showed no significant difference between ESN subjects and the two control groups. 相似文献
128.
Comporti M Arezzini B Signorini C Sgherri C Monaco B Gardi C 《Laboratory investigation; a journal of technical methods and pathology》2005,85(11):1381-1391
Carbon tetrachloride (CCl4)-induced hepatic fibrosis has been considered to be linked to oxidative stress and mediated by aldehydic lipid peroxidation products. In the present study, we investigated whether collagen synthesis is induced by F2-isoprostanes, the most proximal products of lipid peroxidation and known mediators of important biological effects. By contrast with aldehydes, F2-isoprostanes act through receptors able to elicit definite signal transduction pathways. In a rat model of CCl4-induced hepatic fibrosis, plasma F2-isoprostanes were markedly elevated for the entire experimental period; hepatic collagen content also increased. When hepatic stellate cells (HSCs) from normal liver were cultured with F2-isoprostanes in the concentration range found in the in vivo studies (10(-9)-10(-8) M), a striking increase in DNA synthesis (reversed by the thromboxane A2 antagonist SQ 29 548), in cell proliferation and in collagen synthesis was observed. Total collagen content was similarly increased. Moreover, F2-isoprostanes markedly increased the production of transforming growth factor-beta1 by U937 cells, considered a model of liver macrophages. The data provide evidence for the possibility that F2-isoprostanes generated by lipid peroxidation in hepatocytes mediate HSC proliferation and collagen production seen in hepatic fibrosis. 相似文献
129.
Jonathan T. Sims Venkatesh Krishnan Ching-Yun Chang Sarah M. Engle Giacomo Casalini George H. Rodgers Nicoletta Bivi Brian J. Nickoloff Robert J. Konrad Stephanie de Bono Richard E. Higgs Robert J. Benschop Silvia Ottaviani Anabela Cardoso Ajay Nirula Mario Corbellino Justin Stebbing 《The Journal of allergy and clinical immunology》2021,147(1):107-111
130.