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   1319篇
  免费   88篇
  国内免费   7篇
耳鼻咽喉   19篇
儿科学   78篇
妇产科学   53篇
基础医学   181篇
口腔科学   16篇
临床医学   105篇
内科学   305篇
皮肤病学   27篇
神经病学   59篇
特种医学   40篇
外科学   125篇
综合类   17篇
预防医学   66篇
眼科学   68篇
药学   118篇
中国医学   5篇
肿瘤学   132篇
  2024年   1篇
  2023年   24篇
  2022年   35篇
  2021年   69篇
  2020年   53篇
  2019年   46篇
  2018年   68篇
  2017年   41篇
  2016年   58篇
  2015年   48篇
  2014年   79篇
  2013年   68篇
  2012年   121篇
  2011年   106篇
  2010年   53篇
  2009年   44篇
  2008年   84篇
  2007年   96篇
  2006年   76篇
  2005年   51篇
  2004年   54篇
  2003年   45篇
  2002年   36篇
  2001年   5篇
  2000年   1篇
  1999年   15篇
  1998年   7篇
  1997年   7篇
  1996年   8篇
  1995年   2篇
  1994年   3篇
  1993年   2篇
  1992年   3篇
  1991年   3篇
  1990年   1篇
  1989年   1篇
排序方式: 共有1414条查询结果,搜索用时 15 毫秒
91.
The percutaneous approach for RF ablation of liver lesions high up in the dome is always difficult. The authors describe a transpulmonary approach that may be simpler and safer to use.  相似文献   
92.
93.
94.
BACKGROUND: Polycystic ovary syndrome (PCOS) is the commonest endocrine disturbance affecting women in the reproductive age group and encompasses signs of hyperandrogenism, menstrual cycle disturbances and obesity. Some of the symptoms of PCOS may be ameliorated by the combined oral contraceptive pill (COCP). METHODS: A pilot observational study was carried out in a university teaching hospital setting to determine whether the clinical and biochemical features of PCOS are ameliorated by a new COCP, Yasmin, which contains a new progestogen, drosperinone. Treatment with Yasmin was given for 6 months to 17 patients. RESULTS: Thirteen patients (76%) completed 6 months of therapy. Good cycle control was achieved in all patients. Percentage body fat increased, with no overall change in body mass index. Fasting insulin and triglyceride concentrations rose significantly. Serum total testosterone concentrations fell with a concomitant rise in sex hormone binding globulin levels. Hirsutism scores did not change significantly in the 12 women who were clinically hirsute. There was, however, a significant improvement in the acne scores. Four of the 17 patients dropped out of the trial between Cycles 3 and 5 due to side effects. CONCLUSIONS: Yasmin provides good cycle control for women with PCOS, with an improvement in acne over 6 months but not in other symptoms of the syndrome.  相似文献   
95.
Three new spectrophotometric methods for the determination of amlodipine besylate have been proposed. The first two methods, i.e. A and B, are based on the oxidation of the drug with Fe(III) and the estimation of Fe(II) produced after chelation with either 1,10-phenanthroline or 2,2'-bipyridyl at 500 and 515 nm, respectively. The Beer's law was obeyed in the concentration ranges of 2-10 and 4-14 microg ml(-1) with molar absorptivity of 2.9 x 10(4) and 2.7 x 10(4) l mol(-1) cm(-1) for methods A and B, respectively. The third procedure depends on the interaction of amlodipine besylate with ammonium heptamolybdate tetrahydrate, which resulted in the formation of molybdenum blue (lambda(max) 825 nm). The linear dynamic range and the molar absorptivity values were found to be 15-59 microg ml(-1) and 1.8 x 10(4) l mol(-1) cm(-1), respectively. The results of the proposed procedures were validated statistically and compared with those obtained by the reference method. The proposed methods were applied successfully to the determination of amlodipine besylate in commercial tablets.  相似文献   
96.
Different tissue macrophage subsets were immunohistochemically examined in normal endometrial samples collected from proliferative (n=4), peri-ovulatory (n=6) and secretory (n=8) phases of menstrual cycles in women. The different macrophage subsets, namely CD68 (pan macrophage marker), CD44 (transmembrane adhesion molecule), HLA-DR (transmembrane heterodimeric protein involved in antigen presentation) and L1 (calprotectin)-positive cells, as well as, CD45 (common leucocytic antigen)-positive cells were examined on the basis of immunohistochemical staining, and areas of immunoprecipitation were analyzed morphometrically using computer-assisted video imaging system. The stage-specific distribution of receptors for estrogen (ER) and progesterone (PR) in endometrial cells were examined and morphometrically analyzed. There was an increase in the number of CD45+ cells (P < 0.01) and CD68+ cells (P < 0.05) in secretory phase endometrium compared with proliferative and peri-ovulatory phases. There was no remarkable cycle dependent pattern in HLA-DR+ and L1+ cells. However, there was an increase in CD44 immunopositive area in peri-ovulatory (P < 0.05) and in secretory (P < 0.01) phases of endometrium compared with proliferative phase endometrium. A higher (P < 0.01) degree of immunopositivity for ER was observed during peri-ovulatory phase, and for PR, during peri-ovulatory (P < 0.05) and secretory (P < 0.01) phases compared with proliferative phase of cycle. Positive correlations between areas occupied by (i) CD68+ cells and PR (P < 0.01), (ii) HLA-DR+ and L1+ cells (P < 0.05), (iii) CD45+ and CD68+ cells (P < 0.01), (iv) CD45+ and L1+ cells (P < 0.05), and (v) PR and L1+ cells (P < 0.05) were obtained. It appears that the recruitment of different macrophage subsets in human endometrium involves a complex set of endocrine and paracrine factors.  相似文献   
97.
Cytoskeleton disruption is a process by which oxidative stress disrupts cellular function. This study compares and contrasts the effect of oxidative stress on the three major cytoskeleton filaments, microfilaments (MFs), microtubule (MT), and vimentin in human cortical neuronal cell line (HCN2). HCN2 cells were treated with 100 microM tertiary butylhydroperoxide (t-BuOOH), a free radical generating neurotoxin for 1, 3, or 6 h. Cell viability studies demonstrated significant cell death although the morphology studies showed that there was a substantial loss in neurites of neurons treated with t-BuOOH for 6 h. Because the cytoskeleton plays a role in neurite outgrowth, the effect of oxidative stress on the cytoskeletal was studied. In neurons subjected to oxidative stress for 30 min or 1 h, there were no major changes in microfilament distribution though there was altered distribution of microtubule and vimentin filaments as compared to controls. However, loss and disruption of all the three cytoskeletal filaments was observed at later times (3 and 6 h), which was confirmed by Western Blot analysis. Further studies were done to measure the gene expression levels of actin, tubulin, and vimentin. Results indicated that the overall loss of the cytoskeletal proteins in neurons treated with free radical generating toxin might not be a direct result of the downregulation of the cytoskeletal genes. This study shows that free radical generation in human neurons leads to the disruption of the cytoskeleton, though there may be a difference in the susceptibility to oxidative stress among the individual components of the cytoskeletal filaments.  相似文献   
98.
Aniridia (absence of iris) is a congenital, bilateral, uncommon panocular disorder. Whereas the occurrence of aniridia in the general population is 1:50000, it is present in about 1 in 70 patients with Wilm’s tumor. This aniridia is sporadic and Wilm’s tumor in these cases presents at an unusually early age. Aniridia was present in two cases out of 60 cases of Wilm’s tumor operated at PGIMS, Rohtak. Both cases presented below two years of age. The recognition of a child with sporadic aniridia should alert to the increased risk of development of Wilm’s tumor.  相似文献   
99.
100.
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