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   3961篇
  免费   247篇
  国内免费   15篇
耳鼻咽喉   39篇
儿科学   157篇
妇产科学   60篇
基础医学   588篇
口腔科学   37篇
临床医学   318篇
内科学   718篇
皮肤病学   108篇
神经病学   303篇
特种医学   121篇
外科学   504篇
综合类   157篇
预防医学   241篇
眼科学   94篇
药学   363篇
中国医学   37篇
肿瘤学   378篇
  2023年   27篇
  2022年   52篇
  2021年   110篇
  2020年   44篇
  2019年   92篇
  2018年   107篇
  2017年   72篇
  2016年   87篇
  2015年   99篇
  2014年   120篇
  2013年   155篇
  2012年   247篇
  2011年   283篇
  2010年   168篇
  2009年   110篇
  2008年   183篇
  2007年   171篇
  2006年   166篇
  2005年   134篇
  2004年   151篇
  2003年   118篇
  2002年   108篇
  2001年   86篇
  2000年   110篇
  1999年   100篇
  1998年   31篇
  1997年   19篇
  1995年   24篇
  1994年   23篇
  1992年   56篇
  1991年   48篇
  1990年   56篇
  1989年   61篇
  1988年   44篇
  1987年   52篇
  1986年   47篇
  1985年   46篇
  1984年   39篇
  1983年   35篇
  1982年   25篇
  1981年   22篇
  1980年   38篇
  1979年   41篇
  1978年   22篇
  1977年   25篇
  1975年   20篇
  1974年   21篇
  1973年   27篇
  1970年   31篇
  1969年   23篇
排序方式: 共有4223条查询结果,搜索用时 0 毫秒
101.
This study explored the role of the proinflammatory chemokines macrophage inflammatory protein (MIP)-1alpha and macrophage chemoattractant protein (MCP)-1 for development of antileishmanial activity. There was substantial inhibition in nitrite generation in Leishmania donovani-infected macrophages. A marked elevation of nitrite generation and induction of inducible nitric oxide (NO) synthase (iNOS) mRNA was found in chemokine-primed parasite-infected macrophages. Tumor necrosis factor-alpha, which is the priming signal for NO production, was also up-regulated under similar experimental conditions. The priming with chemokine inhibited the multiplication of L. donovani amastigotes within the intramacrophageal milieu. The antileishmanial effect of chemokines was almost completely abrogated when the macrophages were preincubated with l-N-monomethyl arginine, the specific inhibitor of iNOS. The results of this investigation suggest that the CC chemokines MIP-1alpha and MCP-1 orchestrate an antileishmanial armamentarium via the induction of an NO-mediated regulatory mechanism to control the intracellular growth and multiplication of the Leishmania protozoan.  相似文献   
102.
Oral feeding of sodium glycolate (50 mg/d/rat for ten days) caused a significant (P less than 0.001) increase in oxalate and taurine excretion and a decrease in liver protein content (P less than 0.05), glycolic acid oxidase levels (P less than 0.01), and glycolic acid dehydrogenase levels (P less than 0.01) as compared to normal untreated rats. Taurine (100 mg/d/rat), when administered along with glycolate, prevented these effects of glycolate as evident from normal urinary excretion of oxalate, liver protein content, glycolic acid oxidase, and glycolic acid dehydrogenase levels in glycolate- plus taurine-fed animals.  相似文献   
103.
In a series of 74 heart transplant recipients undergoing annual coronary angiography, a coronary artery to right ventricle fistula was observed in 4 patients, an incidence rate of 5.4%, which is much higher than the expected incidence of congenital coronary artery fistula (0.1% to 0.2%). A traumatic origin of the fistulas is unlikely because none of the heart donors had evidence of chest trauma. An endomyocardial biopsy-related etiology of the fistulas is postulated. All fistulas were located in the biopsy sampling area. Patients with a fistula underwent more biopsies before the diagnosis compared with patients without a fistula (20 +/- 11 versus 14 +/- 6, p = 0.05). At least one large arteriole (diameter greater than 0.16 mm) was found on pathologic examination of the biopsy specimens from each of the patients with a fistula (100%) but in only 2 (16.7%) (p less than 0.01) of 12 randomly selected patients without a fistula. The size of the fistula appears to be hemodynamically insignificant in all four patients, judging from angiographic size, normal intracardiac pressures and normal cardiac output values at rest. The diagnosis of a coronary artery to right ventricle fistula is possible and should be entertained at the time of coronary angiography of heart transplant recipients. The clinical significance of the finding is unclear. As long as endomyocardial biopsy remains the diagnostic method of identifying tissue rejection, prevention of the described complication is unlikely.  相似文献   
104.
Hepatitis B immune globulin (HBIG) and immune serum globulin (ISG) were examined in a randomized, double-blind trial to assess their relative efficacies in preventing type B hepatitis after needle-stick exposure to hepatitis B surface antigen (HBsAG)-positive donors. Clinical hepatitis developed in 1.4% of HBIG and in 5.9% of ISG recipients (P = 0.016), and seroconversion (anti-HBs) occurred in 5.6% and 20.7% of them respectively (P less than 0.001). Mild and transient side-effects were noted in 3.0% of ISG and in 3.2% of HBIG recipients. Available donor sera were examined for DNA polymerase (DNAP) and e antigen and antibody (HBeAg; anti-HBE). Both DNAP and HBeAg showed a highly statistically significant correlation with the infectivity of HBsAg-positive donors. Hepatitis B immune globulin remained significantly superior to ISG in preventing type B hepatitis even when the analysis was confined to these two high-risk subgroups. The efficacy of ISG in preventing type B hepatitis cannot be ascertained because a true placebo group was not included.  相似文献   
105.
This study was performed to evaluate the importance of the duration of balloon inflation during PTCA, by comparing two common inflation durations. Patients were randomized to a 30-second inflation protocol (group I, 83 procedures, 109 lesions), or a 60-second protocol (group II, 83 procedures, 115 lesions). There were no differences in baseline characteristics between the two groups, and no subsequent differences in mean inflation number (3.4 +/- 1.6 vs 3.1 +/- 1.6), residual stenosis (34% +/- 17% vs 33% +/- 16%), presence of dissection (29% vs 34%), or clinical success (89% vs 84%), group I versus group II, respectively. The 30-second inflations caused significantly less chest pain score (147 +/- 239 vs 399 +/- 516, P less than 0.001), and ST segment alteration (75 +/- 94 seconds vs 136 +/- 163, P less than 0.05). These results indicate that 60-second inflations do not produce a superior result to 30-second inflations. Furthermore, shorter inflations are much better tolerated.  相似文献   
106.
107.
108.
109.
110.
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