首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   812篇
  免费   51篇
耳鼻咽喉   1篇
儿科学   46篇
妇产科学   11篇
基础医学   112篇
口腔科学   33篇
临床医学   42篇
内科学   195篇
皮肤病学   45篇
神经病学   40篇
特种医学   11篇
外科学   125篇
综合类   5篇
预防医学   16篇
眼科学   2篇
药学   52篇
中国医学   1篇
肿瘤学   126篇
  2023年   5篇
  2022年   6篇
  2021年   9篇
  2019年   8篇
  2018年   14篇
  2017年   11篇
  2016年   22篇
  2015年   24篇
  2014年   33篇
  2013年   21篇
  2012年   41篇
  2011年   39篇
  2010年   31篇
  2009年   23篇
  2008年   42篇
  2007年   50篇
  2006年   40篇
  2005年   34篇
  2004年   31篇
  2003年   30篇
  2002年   27篇
  2001年   26篇
  2000年   36篇
  1999年   19篇
  1998年   18篇
  1997年   20篇
  1996年   14篇
  1995年   7篇
  1994年   11篇
  1993年   8篇
  1992年   9篇
  1991年   15篇
  1990年   10篇
  1989年   7篇
  1988年   10篇
  1987年   10篇
  1986年   8篇
  1985年   6篇
  1984年   4篇
  1983年   7篇
  1979年   3篇
  1978年   5篇
  1977年   7篇
  1969年   4篇
  1967年   5篇
  1958年   4篇
  1957年   9篇
  1956年   4篇
  1955年   7篇
  1954年   6篇
排序方式: 共有863条查询结果,搜索用时 15 毫秒
1.
Big mitogen-activated protein kinase 1 (BMK1), also known as extracellular signal-regulated kinase 5 (ERK5), is a newly identified member of the mitogen-activated protein (MAP) kinase family. Recently, several studies have suggested that BMK1 plays an important role in the pathogenesis of cardiovascular disease. To clarify the pathophysiological significance of BMK1 in the process of vascular remodeling, we explored the molecular mechanisms of BMK1 activation in vascular smooth muscle cells (VSMCs). From the results of co-immunoprecipitation and immunoblotting analyses, it was found that platelet-derived growth factor (PDGF), a known potent mitogen, activated BMK1 and triggered the Gab1-SHP-2 interaction in rat aortic smooth muscle cells (RASMCs). The abrogation of SHP-2 phosphatase activity by transfection of the SHP-2-C/S mutant suppressed PDGF-stimulated BMK1 activation. Infection with an adenoviral vector expressing dominant-negative MEK5alpha, which can suppress PDGF-stimulated BMK1 activation to the control level, inhibited PDGF-induced RASMC migration. Moreover, we observed an increase of BMK1 activation in injured mouse femoral arteries. From these findings, it is suggested that BMK1 activation leads to VSMC migration induced by PDGF via Gab1-SHP-2 interaction, and that BMK1-mediated VSMC migration may play a role in the pathogenesis of vascular remodeling.  相似文献   
2.
Norfloxacin (NFLX, AM-715), a new synthetic antibacterial agent, was administered to 18 child patients with infectious diseases. The patients included 5 boys and 13 girls from 3 to 14 years of ages. They were given orally dosage ranging 5.2-17.9 mg/kg/day for 4 to 14 days. Clinical efficacies were excellent in 1 case, good in 16 cases, unknown in 1 case, hence the total efficacy rate was determined to be 100%. There were no cases which showed side effects of the drug and no abnormal laboratory test values were observed during the treatment.  相似文献   
3.
Abstract  The purpose of this study is to examine whether there are differences in clinical characteristics between Tourette syndrome (TS) patients with and without 'generalized tics' (GT) which involve the entire body, and/or coprolalia. Subjects were 64 patients (55 males and 9 females, mean age, 17.4 ± 7.2 years) who visited Tokyo University's outpatient clinic of neuropsychiatry from 1974 to 1993 and who met criteria for Tourette's disorder of DSM-III-R. Data on clinical characteristics, including tic symptoms and courses of their development, complications and developmental histories, treatment and severity, were collected by systematic chart review of all subjects. Tourette syndrome patients with 'generalized tics' tended to show multiple complex vocal tics more frequently than TS patients without GT. Tourette syndrome patients with coprolalia tended to show significantly higher rates of copropraxia, echolalia, and 'cleaning/washing' compulsion than did the TS patients without coprolalia. Tourette syndrome patients with both GT and coprolalia were classified as the severest group in terms of tic symptoms and social impairment. Tourette syndrome patients who had neither of these morbidities were classified into the mildest group in all aspects. Generalized tics and coprolalia seemed to indicate the severest end of the TS spectrum and seemed to be related with a need of intensive treatment.  相似文献   
4.
Background The role of IgE in airway hyperreaetivity is obscure. Objective In order to clarify the role of IgE in airway hyperreactivity, we investigated the effect of anti-IL-4 monoclonal antibody, rapamycin and interferon-γ on the antigen-induced IgE response, airway eosinophilia and hyperreactivity in mice. Methods Mice were immunized with an antigen (ovalbumin; OA) at intervals of 12 days. OA was inhaled 10 days after the secondary immunization. Twenty-four hours after the last inhalation, airway reactivity to acetylcholine was measured and bronchoalveolar lavage fluid (BALF) was obtained. Results Three inhalations of antigen caused an increase in the number of eosinophils in bronchoalveolar lavage fluid (BALF) and in airway hyperreactivity to acetylcholine with a significant elevation of serum IgE level. Anti-IL-4 at a dose of 1000 μg/animal and rapamycin at doses between 0.1 and 1 mg/kg inhibited the IgE production, but did not affect the airway eosinophilia or hyperreactivity to acetylcholine. In contrast, IFN-γ clearly inhibited the antigen-induced airway eosinophilia and hyperreactivity, but did not affect the IgE antibody production. Conclusion These results suggest that the inhibition of IgE production does not suppress the onset of airway hyperreactivity and eosinophilia in mice, and that IFN-γ inhibits the antigen-induced airway hyperreactivity, probably due to the inhibition of airway eosinophilia.  相似文献   
5.
Decellularized ureter for tissue-engineered small-caliber vascular graft   总被引:1,自引:1,他引:1  
Previous attempts to create small-caliber vascular prostheses have been limited. The aim of this study was to generate tissue-engineered small-diameter vascular grafts using decellularized ureters (DUs). Canine ureters were decellularized using one of four different chemical agents [Triton-X 100 (Tx), deoxycholate (DCA), trypsin, or sodium dodecyl sulfate (SDS)] and the histology, residual DNA contents, and immunogenicity of the resulting DUs were compared. The mechanical properties of the DUs were evaluated in terms of water permeability, burst strength, tensile strength, and compliance. Cultured canine endothelial cells (ECs) and myofibroblasts were seeded onto DUs and evaluated histologically. Canine carotid arteries were replaced with the EC-seeded DUs (n = 4). As controls, nonseeded DUs (n = 5) and PTFE prostheses (n = 4) were also used to replace carotid arteries. The degree of decellularization and the maintenance of the matrix were best in the Tx-treated DUs. Tx-treated and DCA-treated DUs had lower remnant DNA contents and immunogenicity than the others. The burst strength of the DUs was more than 500 mmHg and the maximum tensile strength of the DUs was not different to that of native ureters. DU compliance was similar to that of native carotid artery. The cell seeding test resulted in monolayered ECs and multilayered alpha-smooth muscle actin-positive cells on the DUs. The animal implantation model showed that the EC-seeded DUs were patent for at least 6 months after the operation, whereas the nonseeded DUs and PTFE grafts become occluded within a week. These results suggest that tissue-engineered DUs may be a potential alternative conduit for bypass surgery.  相似文献   
6.
The expression of 13 different α and β V gene segments of the T cell receptor for antigen (TCR) was examined, using V gene-specific MoAbs, on human peripheral blood T lymphocytes from 32 healthy Japanese subjects. In addition, to examine associations between TCR V gene products and HLA alleles, the HLA class I and class II types of all subjects were serologically determined. The reactivities of the anti-TCR V-specific MoAbs were, with some significant exceptions, similar to those previously described in healthy Caucasian subjects. We found a non-random V gene usage as well as a statistically significant bias of the expression of eight Vβ gene products towards the CD4+ subpopulation, and a significant skewness in the usage of Vα12 towards the CD8+ population. Some subjects showed increased reactivities (above 10%) of certain MoAbs, mainly in the CD8+ subpopulation. We found no distinct correlation between any certain HLA class I or II allele and TCR V gene usage in the CD8+ or CD4+ subpopulations, respectively. In conclusion, the pattern of anti-TCR V-specific MoAb reactivities found in CD4+ and CD8+ subsets of peripheral blood lymphocytes of healthy Japanese subjects was in general found to match that previously described in healthy Caucasian subjects.  相似文献   
7.
The purpose of this study was to determine whether the JAK pathway is involved in eosinophil activation and survival through IFN-gamma receptor signalling in human peripheral eosinophils. Eosinophils were purified from the blood of six atopic disease patients by anti-CD16 magnetic bead-negative selection. IFN-gamma significantly up-regulated survival and CD69 expression in 24-48 h cultured eosinophils. Further, IFN-gamma induced tyrosine phosphorylation of JAK2 in eosinophils, as indicated by Western blot analysis. Finally, the specific JAK2 inhibitor AG-490 inhibited the tyrosine phosphorylation of JAK2, IFN-gamma-induced survival and CD69 expression in eosinophils. In conclusion, these results indicate that IFN-gamma induces eosinophil survival and CD69 expression through the activation of JAK2 in peripheral eosinophils, suggesting that JAK2 may play a significant role in eosinophil regulation by IFN-gamma-IFN-gammaR interaction.  相似文献   
8.
A 59-year-old woman with leukorrhea. Aspiration smears were obtained from the uterine cavity. The dominant cellular components were fibrogenic sarcomatous cells, which had ill-defined lacy cytoplasm and a single nucleus with finely granular chromatin. There were occasional naked giant cells, and intracytoplasmic eosinophilic granules. Another infrequent cellular component was adenocarcinoma cells. Histopathologically, adenocarcinoma and spindle cell sarcoma were equivalently identified. Twenty-two cases of homologous carcinosarcoma of the uterine corpus were reviewed cytologically in Japan. Cytodiagnosis before treatment was positive for malignancy of carcinosarcoma in 28.6%. Characteristic cytological findings of this case were the presence of flat sheets of atypical cells with broad cytoplasm. These findings suggest epithelial features. However, the finely granular chromatin pattern and smooth nuclear membrane indicate sarcomatous cells.  相似文献   
9.
Pathologic remodeling of mesangial matrix after glomerular injury is the central biologic feature of glomerular scarring (sclerosis). Transforming growth factor-beta (TGF-beta) and platelet-derived growth factor (PDGF)-BB have been implicated in the development of glomerular scarring in rat and human glomerulonephritis. To clarify molecular and cellular mechanisms involved in abnormal mesangial remodeling, this study focused on the role of alpha1beta1 integrin, a collagen/laminin receptor, in rat mesangial cells, using collagen gel contraction as an experimental model of in vivo collagen matrix remodeling and scar formation. In addition, the influence of TGF-beta and PDGF-BB on mesangial cell (MC)-mediated collagen gel contraction in association with the alpha1beta1 integrin expression was evaluated. Integrin function blocking studies using anti-alpha1, beta1 subunit antibodies indicated that MC-alpha1beta1 integrin is essentially required not only for collagen-dependent adhesion/migration, but also for gel contraction. Protein synthesis and mRNA analysis experiments demonstrated that TGF-beta, but not PDGF-BB, increases the expression of alpha1beta1 integrin in mesangial cells cultured on plastic surface and in collagen gels. The upregulation of alpha1beta1 integrin expression by TGF-beta correlated with increases in gel contraction and collagen-dependent adhesion but not migration of mesangial cells. On the other hand, PDGF-BB enhanced MC-mediated gel contraction and migration without affecting cell adhesion to collagen I. Growth factor-induced collagen-dependent adhesion, migration, and gel contraction were significantly attenuated by incubation with anti-alpha1, beta1 subunit antibodies. Thus, these data indicate that alpha1beta1 integrin-mediated collagen matrix remodeling can be modulated by TGF-beta and PDGF-BB via different mechanisms. Alpha1 integrin-mediated mesangial matrix remodeling induced by TGF-beta or PDGF-BB may be a pathogenic mechanism leading to glomerular scarring.  相似文献   
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号