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21.
Two new genera and three new species of feather mites (Astigmata, Pterolichoidea, Analgoidea) are described from two closely related species of cockatoos, Cacatua galerita (type host) and C. sulphurea (Psittaciformes, Cacatuidae): Astrolabelichus caudatus gen. nov., sp. nov. (Pterolichidae), Psittophagus lacunosus sp. nov. (Pterolichidae), and Cacatualges microdiscus gen. nov., sp. nov. (Xolalgidae). The presence of the same set of mite species on these two species of parrots points to a very close affinity of Cacatua sulphurea and C. galerita and gives additional support for the recent hypothesis of the conspecificity of these birds.  相似文献   
22.
Point mutations in different regions of the tumour necrosis factor-alpha (TNF-alpha) molecule influence anti-tumour cytotoxic/cytostatic activities as well as haemorrhagic tumour necrosis, tumour regression and lethal toxicity in mice. Mutations in the C-terminal region in positions 150 and 155 markedly decrease cytotoxicity for murine L929 fibroblasts and human MCF7 mammary carcinoma cells. Competitive binding experiments with 125I-labelled TNF-alpha revealed that the loss of cytotoxicity is caused by a loss of target cell binding. In contrast to the reduced activity against L929 and MCF7 cells, neither binding to nor cytostatic activity against the human myeloid leukaemia cell lines HL60 and U937 are affected. This target cell type-dependent behaviour is probably due to the fact that L929 and MCF7 cells express different types of TNF receptor compared with myeloid leukaemia cells. While a mutation in position 127 decreases the overall activity of TNF-alpha, a deletion of four N-terminal amino acids does not reduce biological activity. In vivo the TNF mutants differed in their anti-tumour effects and lethal toxicity, but a segregation of anti-tumour activity and toxicity was not observed.  相似文献   
23.
Recombinant FimH adhesins of type 1 fimbriae from Salmonella enterica serovar Gallinarum biovars Gallinarum and Pullorum, in contrast to those of Salmonella enterica serovar Typhimurium, did not bind to high-mannose oligosaccharides or to human colon carcinoma HT-29 cells. However, mutated FimH proteins from biovar Gallinarum and biovar Pullorum, in which the isoleucine at position 78 was replaced by the threonine found in S. enterica serovar Typhimurium, bound well to glycoproteins carrying high-mannose oligosaccharides and colon carcinoma cells. The loss of sugar-binding properties by biovar Gallinarum and biovar Pullorum FimH adhesins, which are a part of the type 1 fimbriae, is most probably the result of a single T78I mutation, as was proven by site-directed mutagenesis of FimH proteins.  相似文献   
24.
Racemic lactide was polymerized with various initiators containing Zn and Al, and the structures of the obtained polymers were determined by means of 13C NMR spectroscopy. The extent of transesterification reactions was calculated on the basis of the analysis of the methine carbon signal in the polymer 13C NMR spectra. Three groups of initiators can be distinguished in view of their influence on transesterification: ZnCl2 exhibits the strongest transesterification activity, ZnEt2 and ZnEt2/Al(OiPr)3 are among those of medium activity, and Al(acac)3 does not show transesterification activity at all.  相似文献   
25.
D I Pritchard  N M Ali    J M Behnke 《Immunology》1984,51(4):633-642
The suppression of immune responsiveness to heterologous antigenic stimulation during concurrent infection with Nematospiroides dubius was reproduced using soluble antigens derived from adult parasites. Immunosuppression appeared to be selective in that the administration of equivalent quantities of an irrelevant heterogeneous antigen had no immunosuppressive effect, and suppression was transferable using spleen cells from parasite antigen-treated donors. The differential immunomodulatory activity of parasite antigens from a variety of nematode species suggested that a correlation might exist between suppressor activity and chronicity of infection. A role for suppressor T cell activity in the infected host was implicated by the restorative effect of 2'deoxyguanosine treatment on the immune response, and non-specific suppressor cell activity was detected in splenocyte populations from infected mice. It is suggested that a parasite-induced defect in antigen processing led to the induction of suppressor cell activity in the infected host and that this may be one mechanism of parasite survival. The relevance of these observations to vaccination against chronic gastrointestinal nematode infections is discussed.  相似文献   
26.
BACKGROUND: Chronic inflammation with tissue eosinophilia plays a key role in the pathogenesis of asthma and nasal polyps in patients with aspirin hypersensitivity. OBJECTIVE: To evaluate the expression of vascular cell adhesion molecule 1 (VCAM-1) and intercellular adhesion molecule I (ICAM-1) and their ligands (the integrins lymphocyte function-associated antigen 1 and very late-activation antigen 4 [VLA-4]) in nasal polyps of patients with aspirin hypersensitivity compared with aspirin-tolerant individuals. METHODS: Immunohistochemical studies were performed using a peroxidase method and monoclonal antibodies on 6-microm-thick cryostat sections cut from frozen polyps collected during elective surgery from 21 aspirin-sensitive and 23 aspirin-tolerant patients. RESULTS: The mean +/- SD values of the semiquantitatively evaluated immunoexpression of ICAM-1, VCAM-1, and VLA-4 were significantly increased in patients with aspirin hypersensitivity compared with aspirin-tolerant patients (1.7 +/- 0.8 vs 0.9 +/- 0.8, P < .003; 1.8 +/- 0.8 vs 0.8 +/- 0.8, P < .001; and 2.2 +/- 0.7 vs 1.3 +/- 0.7, P < .001, respectively), whereas the mean +/- SD values of the expression of lymphocyte function-associated antigen 1 did not differ significantly (2.4 +/- 0.5 vs 2.2 +/- 0.9; P = .57). We found a correlation between the immunoexpression of VCAM-1 and its ligand VLA-4 in all studied tissue samples (r = 0.4; P < .02). CONCLUSIONS: In nasal polyps of aspirin-hypersensitive patients, up-regulation of the adhesion molecules ICAM-1 and VCAM-1 and the integrin VLA-4 may play an important role in the development of chronic eosinophilic inflammation.  相似文献   
27.
Characterization of the human placental membrane receptor for human 125I-IgG is described. The receptor bound specifically both monomers and aggregates of human IgG. Human colostral IgA, bovine, sheep, pig, and horse IgG were not bound. No effect of pH in the range 6.6–7.4, ionic strength in the range 0.1–0.5, and temperature between 4 and 45°C on the binding was found. A water-soluble fraction containing the active receptor (glycoprotein fraction-PGP) was obtained from the placental membranes using lithium diiodosalicylate. The solubilized receptor interacted with IgG better at 4°C than at 20°C or 37°C. The results on replacement of monomeric IgG by aggregated IgG, and vice versa, suggest that both monomers and aggregates of human IgG, were bound to the same receptor sites. The apparent association constant for monomeric human IgG was 0.86 ± 0.2 × 107 mole?1, and 2.0 ± 0.16 × 1015 IgG molecules were bound per l mg of the membrane protein. Formaldehyde (0.1%), 2-mercaptoethanol (50 mM), and periodate (4 mM) showed no effect on the binding properties of the membrane-bound and on the solubilized receptor, as well. Higher concentrations of periodate (10 mM or 20 mM) decreased the binding of IgG to membranes but showed no effect on the water-soluble receptor. Both the membrane-bound and the solubilized receptor were sensitive to papain. Pronose abolished the receptor activity after prolonged proteolysis only. Neuraminidase did not affect the activity of the receptor. The decrease of the binding activity of the membrane-bound receptor by trypsin and phospholipase C was due to a release of a material containing an active receptor. No effect of trypsin or phospholipase C on the activity of solubilized receptor was observed. The results obtained suggest a protein character of the placental Fc receptor. After electrophoresis of 125I-labeled solubilized receptor in polyacrylamide gel in the presence of SDS, 2 major protein peaks with molecular weights of 74,000 and 104,000 and 3 minor peaks with molecular weights of 56,000, 144,000, and 163,000 were found.  相似文献   
28.
Cystic fibrosis (CF) is inherited as an autosomal recessive disorder. It is caused by mutations in the protein-coding gene of chromosome 7, resulting in chronic pulmonary disease and pancreatic insufficiency. The disease affects all secretory epithelia, including the eye. The pathogenesis of ocular changes in CF is still unknown, but the involvement of immunologic processes in patients with CF has been studied in recent years. We measured interleukin-8 (IL-8) and interferon-gamma (IFN-gamma) levels in tears in a group of patients and a group of normal controls to determine if the levels of these cytokines are elevated in CF. The levels of these cytokines in tears and the clinical severity of CF and eye disease were compared. Tear samples were collected from 24 patients with CF at the department of pediatric diseases, Medical University of Bialystok, Poland. Cytokine levels were determined by ELISA. Ophthalmic examinations, including tests for keratoconjunctivitis sicca (dry eye), were used to study the ocular surface. The tear levels of IL-8 and IFN-gamma in the CF patients were significantly higher than those in controls. The clinical severity of CF correlated significantly with the IL-8 and IFN-gamma levels. We found positive correlation between the tear levels of IFN-gamma and dry eye findings in CF patients. Our results suggest that the inflammatory cytokines IL-8 and IFN-gamma may play key roles in the regulation of ocular surface inflammation and the immunologic reaction in patients with CF. The tear levels of IL-8 and IFN-gamma may be candidate markers for evaluation of the clinical status of CF and eye disease. These findings help to provide a new insight into the pathogenesis of dry eye in patients with CF and provide potential targets for therapy.  相似文献   
29.
The clinical implications of increased cytokine levels after major surgery remain unclear. In this study, systemic concentration of a spectrum of cytokines, including interleukins IL-6, IL-8, IL-10, IL-1ra, and soluble tumor necrosis factor receptor-I (sTNF-RI) was examined in patients with and without postoperative septic complications following colorectal surgery. Although there were no significant changes in IL-1, TNF-, and IL-8 serum levels during the observation period, there was a significant rise in IL-6, IL-1ra, and sTNF-RI concentrations in the entire group of patients between postoperative day 1 and 14. There were no differences between the group without and with local complications when IL-6, IL-1ra, and IL-10 were examined. The serum levels of sTNF-RI, IL-1ra, and IL-6 were found to be sensitive indicators of the pro- and anti-inflammatory response to the surgical trauma, but only sTNF-RI turned out to be a sensitive early marker of local septic postoperative complications in patients with colorectal carcinoma.  相似文献   
30.
Dilated cardiomyopathy (DCM) is one of the most common causes of heart failure with a prevalence of 1:2500. There are several primary and secondary etiologic factors, including gene mutations, infection agents, particularly viruses, toxins, autoimmune, and systemic disorders, and pheochromocytoma, neuromuscular, metabolic, mitochondrial, and nutritional disorders. However, a precise diagnosis can be reached only in no more than 50% of all cases. Herein, we report a rare case of hepatic damage and severe DCM as a consequence of relatively popular socially used narcotic-Ecstasy (3,4-methylenedioxy-N-methylamphetamine [MDMA]).  相似文献   
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