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   31401篇
  免费   2322篇
  国内免费   460篇
耳鼻咽喉   634篇
儿科学   515篇
妇产科学   677篇
基础医学   4463篇
口腔科学   485篇
临床医学   2583篇
内科学   7146篇
皮肤病学   956篇
神经病学   2172篇
特种医学   1620篇
外科学   4252篇
综合类   524篇
一般理论   15篇
预防医学   1276篇
眼科学   920篇
药学   2745篇
中国医学   341篇
肿瘤学   2859篇
  2023年   174篇
  2022年   413篇
  2021年   991篇
  2020年   497篇
  2019年   817篇
  2018年   948篇
  2017年   682篇
  2016年   906篇
  2015年   1237篇
  2014年   1461篇
  2013年   1676篇
  2012年   2452篇
  2011年   2529篇
  2010年   1522篇
  2009年   1302篇
  2008年   1846篇
  2007年   1760篇
  2006年   1592篇
  2005年   1524篇
  2004年   1279篇
  2003年   1244篇
  2002年   1130篇
  2001年   755篇
  2000年   678篇
  1999年   636篇
  1998年   246篇
  1997年   226篇
  1996年   200篇
  1995年   171篇
  1994年   150篇
  1993年   98篇
  1992年   305篇
  1991年   230篇
  1990年   264篇
  1989年   257篇
  1988年   243篇
  1987年   198篇
  1986年   177篇
  1985年   161篇
  1984年   140篇
  1983年   111篇
  1982年   79篇
  1981年   71篇
  1980年   69篇
  1979年   124篇
  1978年   82篇
  1977年   66篇
  1975年   59篇
  1974年   53篇
  1972年   49篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
201.
202.
Phosphatidylinositol 3-kinase (PI3K) is critical player in cell proliferation and survival. The effects of LY294002 and wortmannin, inhibitors of PI3K, on nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) expression in lipoploysaccharide (LPS)-induced Raw 264.7 cells were investigated. Significant inhibition of LPS-induced protein kinase B (PKB, Akt) phosphorylation occurred at 25 microM LY294002 or 0.5 microM wortmannin. At the same concentrations, LY294002, but not wortmannin, significantly inhibited NO production and iNOS expression. LY303511, an inactive analogue of LY294002, also inhibited NO production and iNOS expression. In addition, LY294002 and LY303511 significantly inhibited the DNA binding activity of NF-kappaB and NF-kappaB dependent reporter gene expression. These results suggest that LY294002 inhibits iNOS expression at least in part via inhibition of NF-kappaB activation, independent of PI3K.  相似文献   
203.
Tetanus is uncommon in Korea due to the introduction of vaccination programs and advances in public health. A case of maternal tetanus occurred on the 9 day postpartum in a 29-yr-old woman, who had not received a 10-yr-booster of tetanus-diphtheria toxoid after receiving the primary series of tetanus-toxoid-containing vaccine. There has hitherto been no reports on maternal tetanus in Korea. This case illustrates that tetanus remains a medical problem, principally among non- and under-immunized adults. The only way to fully prevent this disease is to ensure adequate immunization in all adults.  相似文献   
204.
BACKGROUND AND PURPOSE: This study was conducted to investigate whether changes in the complete blood count (CBC)/differential count (DC) and C-reactive protein (CRP) were correlated to Kawasaki disease (KD) with coronary artery lesions (CALs). METHODS: A retrospective analysis was performed of all children with KD at Chang Gung Memorial Hospital at Kaohsiung from 2001 to 2006. KD patients were divided into those with and without CALs for testing of correlations with changes in CBC/DC and CRP levels. RESULTS: A total of 147 patients were enrolled for this analysis. Serial CBC/DC and CRP measurements and echocardiographic data for determination of CAL formation were obtained before and after intravenous immunoglobulin (IVIG) treatment. There were 44 (29%) KD patients having CAL formation (>3 mm in diameter of internal lumen). There was no significant difference in terms of age distribution and major diagnostic criteria between KD patients with and without CALs. Male KD patients, however, had a significantly higher rate of CAL formation (p=0.009). In multivariate logistical regression analysis, persistent monocytosis after IVIG treatment was the only factor significantly correlated to CAL formation (p=0.003). CONCLUSIONS: Of the febrile routine measurements of CBC/DC and CRP in KD, persistent monocytosis after IVIG treatment was correlated to CAL formation. Further studies to clarify the mechanism of monocytosis may help prevent the CALs of KD.  相似文献   
205.
蝶鞍区塑化薄片断层解剖学研究   总被引:5,自引:0,他引:5  
张绍祥  刘正津  何光篪 《解剖学报》1998,29(4):337-341,I001
为了给临床蝶鞍区手术提供详细的解剖学资料,用中年男性标本30例,采用Plastination技术,分别作成蝶区连续横、矢、冠状薄片断层标本,进行解剖学观测,结果显示:董体的左右径大于前后径或上下径,对于垂体病变,宜进行三方位对照观察,以了解垂体的形态变化。展神经与海绵窦外侧壁之间有间隙存在,说明展神经并不走行于外侧壁中,而是位海绵窦内。紧贴视交叉的外侧,颈内动脉由海绵窦段的前升冲突芊  相似文献   
206.
Detection of T suppressor cells in patients with organ allografts   总被引:16,自引:0,他引:16  
Specific immunosuppression of host's immune response to donor HLA antigens has been a major goal to clinical transplantation. Recent evidence has been accumulating to show that a distinct population of T cells expressing the CD8(+) CD28(-) phenotype display suppressor function and inhibit Th activation and proliferation by modulating the APC function. To assess the presence of Ts in transplant recipient's circulation, we have developed a flow cytometry method that measures the expression of costimulatory molecules on donor APC exposed to recipient Th and Ts. Our results demonstrate that quantitation of the capacity of CD8(+) CD28(-) T cells from patient circulation to suppress the activation of costimulatory molecules (CD80, CD86) on donor APC offers a reliable tool for monitoring specific immunosuppression against the graft in solid organ transplantation.  相似文献   
207.
208.
Hematological indices were determined in a group of 427 elderly Chinese subjects over 60 years old; reference ranges were established after excluding subjects with hemoglobinopathies or diseases giving rise to anemia and those with values less or greater than 3 SD from the mean. The values were similar to those for elderly Caucasians. All the red cell indices were significantly higher in men than women, possibly reflecting the influence of androgens on bone marrow function. Previously reported age-related decline in hemoglobin, red cell count and hematocrit from studies of all age groups was not seen in men or women above age 60 years, but a fall in platelet count with age, which had not been previously reported, was observed. There were no age-related changes in any other indices. Reference ranges were lower for Hb, MCV, and MCH in men and women, compared to those derived from a study of Chinese of all age groups. The prevalence of anemia due to disease and hemoglobinpathies in this population was 6.4% in men and 6.3% in women.  相似文献   
209.
Current trends and new approaches in the management of diabetes mellitus   总被引:4,自引:0,他引:4  
Current trends in the management of type 2 diabetes mellitus, based on the 20-year United Kingdom Prospective Diabetic Study, include intensive treatment to control the blood glucose level and blood pressure in order to prevent or delay microvascular and cardiovascular complications. In the new millennium, type 2 diabetes will become epidemic in developing countries. If diabetes were to develop in 10% of the 1.2 billion population of China, the expense of intensive treatment would be immense. Laboratory tests are useful for detecting risk factors before the onset of the disease and convincing the general public to take preventive measures. Glucose tolerance testing is one of these tests. When glucose tolerance is impaired, 25% of beta-cell function is lost. Determining the plasma proinsulin level is another useful evaluation; impaired glucose tolerance accompanied by increased plasma proinsulin level is indicative of an enhanced risk that type 2 diabetes will develop within 5 years. Educating the public about eating a healthy diet and exercising may prevent the development of diabetes and thereby reduce the global prevalence of type 2 diabetes.  相似文献   
210.
Previous studies have suggested that human follicular fluid contains factors that reduce the zona-binding capacity of spermatozoa. The present study provides further evidence of the existence of such factors. Using the hemizona binding assay (HZA), we have shown that the inhibitory effect of human follicular fluid on the zona-binding capacity of spermatozoa is concentration-dependent, an inhibitory effect being detected when the concentration of human follicular fluid was > or = 10%. A 1% concentration of human follicular fluid did not possess this inhibitory activity. Heating human follicular fluid at 56 degrees C for 30 min did not affect its inhibitory properties; treatment with proteinase-K abolished such inhibition. Human follicular fluid was fractionated sequentially by concanavalin-A affinity chromatography, Mono Q ion-exchange chromatography and Superose-12 gel filtration. The zona binding inhibitory activity resided in the fraction which bound to the lectin and Mono Q column and contained molecules with native molecular weights of 32 and 192 kDa. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis analysis suggested that the 192 kDa glycoprotein was a tetramer, while the 32 kDa glycoprotein remained as a single molecular species under denaturing conditions. We conclude that two glycoproteins were responsible for the zona binding inhibitory activity of human follicular fluid. The physiological role of these factors remains unclear.   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