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91.
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CM Lange S Bibert Z Kutalik P Burgisser A Cerny JF Dufour A Geier TJ Gerlach MH Heim R Malinverni F Negro S Regenass K Badenhoop J Bojunga C Sarrazin S Zeuzem T Müller T Berg PY Bochud D Moradpour;Swiss Hepatitis C Cohort Study Group 《PloS one》2012,7(7):e40159
Background
To perform a comprehensive study on the relationship between vitamin D metabolism and the response to interferon-α-based therapy of chronic hepatitis C.Methodology/Principal Findings
Associations between a functionally relevant polymorphism in the gene encoding the vitamin D 1α-hydroxylase (CYP27B1-1260 rs10877012) and the response to treatment with pegylated interferon-α (PEG-IFN-α) and ribavirin were determined in 701 patients with chronic hepatitis C. In addition, associations between serum concentrations of 25-hydroxyvitamin D3 (25[OH]D3) and treatment outcome were analysed. CYP27B1-1260 rs10877012 was found to be an independent predictor of sustained virologic response (SVR) in patients with poor-response IL28B genotypes (15% difference in SVR for rs10877012 genotype AA vs. CC, p = 0.02, OR = 1.52, 95% CI = 1.061–2.188), but not in patients with favourable IL28B genotype. Patients with chronic hepatitis C showed a high prevalence of vitamin D insufficiency (25[OH]D3<20 ng/mL) during all seasons, but 25(OH)D3 serum levels were not associated with treatment outcome.Conclusions/Significance
Our study suggests a role of bioactive vitamin D (1,25[OH]2D3, calcitriol) in the response to treatment of chronic hepatitis C. However, serum concentration of the calcitriol precursor 25(OH)D3 is not a suitable predictor of treatment outcome. 相似文献94.
95.
Processing of leaf litter is an important function in many environments and is influenced strongly by microorganisms. We investigated interactions between an aquatic hyphomycete, Tetrachaetum elegans, and two bacteria from the Cytophaga-Flavobacterium-Bacteroides group, that were isolated from decaying leaves in a stream. Laboratory experiments were used to examine interactions, as indicated by growth, between bacteria and fungi on sugar maple (Acer saccharum) leaves. Responses to amendments with labile dissolved organic carbon (DOC) were also examined. Fungal biomass was not affected by glucose amendment or bacterial presence. Likewise, bacterial biomass did not respond consistently to the glucose amendment, nor did the fungus affect bacterial biomass. In general, we found little evidence of resource competition or facilitation, in contrast to other studies. Our experiments suggest that fungal–bacterial interactions are not always significant and may depend on environmental conditions and the types of microorganisms examined. 相似文献
96.
Sensitivity of leaf size and shape to climate within Acer rubrum and Quercus kelloggii 总被引:1,自引:1,他引:0
* Variation in the size and shape (physiognomy) of leaves has long been correlated to climate, and paleobotanists have used these correlations to reconstruct paleo-climate. Most studies focus on site-level means of largely nonoverlapping species sets. The sensitivity of leaf shape to climate within species is poorly known, which limits our general understanding of leaf-climate relationships and the value of intraspecific patterns for paleoclimate reconstructions. * The leaf physiognomy of two species whose native North American ranges span large climatic gradients (Acer rubrum and Quercus kelloggii) was quantified and correlated to mean annual temperature (MAT). Quercus kelloggii was sampled across a wide elevation range, but A. rubrum was sampled in strictly lowland areas. * Within A. rubrum, leaf shape correlates with MAT in a manner that is largely consistent with previous site-level studies; leaves from cold climates are toothier and more highly dissected. By contrast, Q. kelloggii is largely insensitive to MAT; instead, windy conditions with ample plant-available water may explain the preponderance of small teeth at high elevation sites, independent of MAT. * This study highlights the strong correspondence between leaf form and climate within some species, and demonstrates that intraspecific patterns may contribute useful information towards reconstructing paleoclimate. 相似文献
97.
Franζoise Stoll-Keller 《中国病毒学》2008,23(2)
Hepatitis C virus (HCV) is a member of the Flaviviridae family and causes acute and chronic hepatitis. Chronic HCV infection may result in severe liver damage including liver cirrhosis and hepatocellular carcinoma. The liver is the primary target organ of HCV, and the hepatocyte is its primary target cell. Attachment of the virus to the cell surface followed by viral entry is the first step in a cascade of interactions between the virus and the target cell that is required for successful entry into the cell and initiation of infection. This step is an important determinant of tissue tropism and pathogenesis; it thus represents a major target for antiviral host cell responses, such as antibody-mediated virus neutralization. Following the development of novel cell culture models for HCV infection our understanding of the HCV entry process and mechanisms of virus neutralization has been markedly advanced. In this review we summarize recent developments in the molecular biology of viral entry and its impact on pathogenesis of HCV infection, development of novel preventive and therapeutic antiviral strategies. 相似文献
98.
Joachim Lupberger Mirjam B. Zeisel Anita Haberstroh Eva K. Schnober Sophie Krieger Eric Soulier Christine Thumann Cathy Royer Samira Fafi-Kremer Catherine Schuster Françoise Stoll-Keller Hubert E. Blum Thomas F. Baumert 《中国病毒学》2008,23(2):124-131
Hepatitis C virus (HCV) is a member of the Flaviviridae family and causes acute and chronic hepatitis. Chronic HCV infection
may result in severe liver damage including liver cirrhosis and hepatocellular carcinoma. The liver is the primary target
organ of HCV, and the hepatocyte is its primary target cell. Attachment of the virus to the cell surface followed by viral
entry is the first step in a cascade of interactions between the virus and the target cell that is required for successful
entry into the cell and initiation of infection. This step is an important determinant of tissue tropism and pathogenesis;
it thus represents a major target for antiviral host cell responses, such as antibody-mediated virus neutralization. Following
the development of novel cell culture models for HCV infection our understanding of the HCV entry process and mechanisms of
virus neutralization has been markedly advanced. In this review we summarize recent developments in the molecular biology
of viral entry and its impact on pathogenesis of HCV infection, development of novel preventive and therapeutic antiviral
strategies.
相似文献
99.
Opatowski L Temime L Varon E Leclercq R Leclerc R Drugeon H Boëlle PY Guillemot D 《PloS one》2008,3(5):e2089
Background
Despite increasingly frequent bacterial resistance to antibiotics, antibacterial innovation is rare. Ketolides constitute one of the very few new antibiotic classes active against Streptococcus pneumoniae developed during the last 25 years. Their mechanism of action resembles that of macrolides, but they are unaffected by common resistance mechanisms. However, cross-resistance to ketolides has been observed in some macrolide-resistant strains. We examined how new antibiotic exposure may affect overall pneumococcal resistance patterns in the population. The aims of this study were to assess the potential dissemination of newly emerged resistances and to control the selection of strains already multiresistant to existing antimicrobials.Methodology/Principal Findings
We developed an age-structured population model for S. pneumoniae transmission in a human community exposed to heptavalent vaccine, and β-lactams, macrolides and ketolides. The dynamics of intra-individual selection of resistant strains under antibiotic exposure and interindividual transmission were simulated, with antibiotic-specific resistance mechanisms defining the path to co-resistances and cross-resistances, and parameters concerning the French situation. Results of this simulation study suggest that new antibiotic consumption could markedly slow the diffusion of multiresistant strains. Wider use was associated with slower progression of multiresistance. When ketolides were prescribed to all ages, resistance to them reached 10% after >15 years, while it took >40 years when they were prescribed only to adults. In the scenario according to which new antibiotics totally replaced former antimicrobials, the β-lactam resistance rate was limited at 70%.Conclusions
In a context of widespread vaccination and rational use of antibiotics, innovative antibiotic, prescribed to all age groups, may have an added impact on multiresistant-strain dissemination in the population. 相似文献100.