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   468篇
  免费   45篇
  国内免费   105篇
儿科学   28篇
妇产科学   5篇
基础医学   43篇
口腔科学   32篇
临床医学   102篇
内科学   103篇
皮肤病学   6篇
神经病学   8篇
特种医学   70篇
外科学   23篇
综合类   40篇
预防医学   33篇
眼科学   5篇
药学   54篇
中国医学   1篇
肿瘤学   65篇
  2021年   4篇
  2020年   2篇
  2019年   3篇
  2018年   5篇
  2017年   7篇
  2016年   8篇
  2015年   12篇
  2014年   6篇
  2013年   17篇
  2012年   6篇
  2011年   12篇
  2010年   17篇
  2009年   17篇
  2008年   4篇
  2007年   58篇
  2006年   12篇
  2005年   26篇
  2004年   16篇
  2003年   10篇
  2002年   14篇
  2001年   7篇
  2000年   14篇
  1999年   7篇
  1998年   45篇
  1997年   36篇
  1996年   38篇
  1995年   19篇
  1994年   23篇
  1993年   15篇
  1992年   12篇
  1991年   6篇
  1990年   12篇
  1989年   13篇
  1988年   17篇
  1987年   16篇
  1986年   13篇
  1985年   6篇
  1984年   4篇
  1983年   4篇
  1982年   3篇
  1981年   7篇
  1980年   5篇
  1979年   3篇
  1977年   7篇
  1976年   7篇
  1975年   4篇
  1974年   5篇
  1973年   8篇
  1965年   1篇
  1960年   1篇
排序方式: 共有618条查询结果,搜索用时 15 毫秒
91.
侯宁  徐丽君 《药学学报》1992,27(10):738-742
设计合成了新型缩氨基硫脲衍生物4-氨基-3-(呋喃-2)-5-巯基-1,2,4-三唑及其十种不同醛的Schiff碱衍生物,并进行了抑菌实验。结果表明:Schiff碱化合物结构中的甲亚胺基是该类化合物的活性功能基。苯环上更换不同的取代基对其活性有一定的影响,其中化合物4-(5-硝基亚糠基氨基)-3-(呋喃-2)-5-巯基-1,2,4-三唑(Ik)抗菌活性最高且抗菌谱最广;化合物4-亚水杨基氨基-3-(呋喃-2)-5-巯基-1,2,4-三唑(Ib)具有较强的抑霉活性。  相似文献   
92.
The effect of cyclodextrin (beta-CD) on the solubility and dissolution rate of various paracetamol dispersion powders (1:1 w/w), and tablets was studied. Lower solubility was exhibited by a spray dried solid dispersion made from paracetamol-Ethocel-Macrogol 6000 (95:2:3). The improvement in solubility was influenced by complexation with beta-CD and the crystalline nature of the powder products made by different procedures. The difference in crystallinity was confirmed by X-ray powder diffraction patterns. The dissolution rate of paracetamol from tablets made from the solid dispersions was satisfactory compared with paracetamol alone. The differences between the dissolution rate from the examined paracetamol tablets resulted from the different solubility of each powder and from the structural changes of particles which influenced the consolidation of the tablet mass.  相似文献   
93.
In human immune deficiency virus (HIV)-seropositive hemophilia patients, a low number of CD4 + lymphocytes is found, as well as a low CD4+/CD8+ ratio. In previous studies, it has been shown that antigen- specific T-helper cell (CD4+) function was present and no excessive antigen-specific T-suppressor cell (CD8+) function could be demonstrated. In this report, we studied another activity of CD4+ cells, namely the capacity to induce T-suppressor cell activity. The results clearly show a selective dysfunction of CD4+ suppressor-inducer (Tsi) cell function. Since these HIV-seropositive hemophilia patients showed the presence of activated B cells in the peripheral circulation refractory to antigen-specific T-helper cell signals and secreting specific antibodies spontaneously, we raised the hypothesis that the activated B cells in the patients activate the Tsi cells in vivo. This constant activation leads to a functional exhaustion of the Tsi cell pool.  相似文献   
94.
95.
IntroductionAcute respiratory distress syndrome (ARDS) is a common clinical syndrome with high mortality and long-term morbidity. To date there is no effective pharmacological therapy. Aspirin therapy has recently been shown to reduce the risk of developing ARDS, but the effect of aspirin on established ARDS is unknown.MethodsIn a single large regional medical and surgical ICU between December 2010 and July 2012, all patients with ARDS were prospectively identified and demographic, clinical, and laboratory variables were recorded retrospectively. Aspirin usage, both pre-hospital and during intensive care unit (ICU) stay, was included. The primary outcome was ICU mortality. We used univariate and multivariate logistic regression analyses to assess the impact of these variables on ICU mortality.ResultsIn total, 202 patients with ARDS were included; 56 (28%) of these received aspirin either pre-hospital, in the ICU, or both. Using multivariate logistic regression analysis, aspirin therapy, given either before or during hospital stay, was associated with a reduction in ICU mortality (odds ratio (OR) 0.38 (0.15 to 0.96) P = 0.04). Additional factors that predicted ICU mortality for patients with ARDS were vasopressor use (OR 2.09 (1.05 to 4.18) P = 0.04) and APACHE II score (OR 1.07 (1.02 to 1.13) P = 0.01). There was no effect upon ICU length of stay or hospital mortality.ConclusionAspirin therapy was associated with a reduced risk of ICU mortality. These data are the first to demonstrate a potential protective role for aspirin in patients with ARDS. Clinical trials to evaluate the role of aspirin as a pharmacological intervention for ARDS are needed.  相似文献   
96.
97.
98.
Clark  LJ; Chan  LS; Powars  DR; Baker  RF 《Blood》1981,57(4):675-678
Negative charges on the external surface of red cells were visualized by colloidal iron hydroxide labelling of 50% of the membrane area after osmotic hemolysis and glutaraldehyde fixation. Counts were made over randomly selected areas on electron micrographs at 350,000 x magnification. Statistical analyses showed that at the 95% level of confidence there was no significant difference between oxygenated normal (AA) and sickle (SS) cells in either the distribution or the density of negative charges.  相似文献   
99.
100.
From March to August 1984, 26 patients with hereditary hemolytic anemia in northeastern Ohio developed acute, profound red cell aplasia. The patients included 14 males and 12 females 2 to 23 years old, with sickle cell anemia (20 cases), hemoglobin SC-disease (4 cases), sickle- beta-thalassemia (1 case), or hereditary spherocytosis (1 case). All had an acute onset of severe reticulocytopenia and anemia and prodromal symptoms of illness including fever, abdominal symptoms, headache, and arthralgias. Twenty-two received transfusions. Reticulocytosis occurred spontaneously within 2 to 14 days of presentation. In five acute-phase sera, 10(8) to 10(12) viral particles/mL were detected by electron microscopy. Human parvovirus B19 DNA was demonstrated in high concentration by hybridization in the same five acute-phase sera and in low concentration in sera of eight additional patients. The five highly viremic sera inhibited erythroid colony formation in vitro. B19- specific IgM was detected in sera of 24/26 patients, and B19-specific IgG in 21 of 22 patients tested. Our results indicate that human parvovirus B19 was the etiologic agent in this large epidemic of life- threatening acute red cell aplasia in patients with hereditary hemolytic anemia.  相似文献   
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