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   4382篇
  免费   266篇
  国内免费   28篇
耳鼻咽喉   28篇
儿科学   137篇
妇产科学   63篇
基础医学   648篇
口腔科学   71篇
临床医学   343篇
内科学   1099篇
皮肤病学   183篇
神经病学   373篇
特种医学   111篇
外科学   420篇
综合类   14篇
预防医学   205篇
眼科学   94篇
药学   406篇
中国医学   9篇
肿瘤学   472篇
  2024年   8篇
  2023年   40篇
  2022年   53篇
  2021年   115篇
  2020年   72篇
  2019年   97篇
  2018年   117篇
  2017年   101篇
  2016年   123篇
  2015年   123篇
  2014年   138篇
  2013年   185篇
  2012年   290篇
  2011年   325篇
  2010年   167篇
  2009年   168篇
  2008年   310篇
  2007年   293篇
  2006年   297篇
  2005年   295篇
  2004年   312篇
  2003年   301篇
  2002年   280篇
  2001年   44篇
  2000年   33篇
  1999年   32篇
  1998年   38篇
  1997年   39篇
  1996年   30篇
  1995年   29篇
  1994年   29篇
  1993年   28篇
  1992年   18篇
  1991年   22篇
  1990年   14篇
  1989年   12篇
  1988年   15篇
  1987年   8篇
  1986年   16篇
  1985年   7篇
  1984年   8篇
  1983年   8篇
  1982年   9篇
  1981年   5篇
  1980年   4篇
  1979年   4篇
  1977年   3篇
  1976年   2篇
  1965年   1篇
  1957年   1篇
排序方式: 共有4676条查询结果,搜索用时 15 毫秒
41.
42.
43.
44.
45.
Experimental autoimmune myocarditis (EAM) has been used as a model for human myocarditis. We previously demonstrated that blockade of B7/CD28 or CD40/CD40 ligand (CD40L) had a potential preventive effect on EAM, but less therapeutic effect on ongoing EAM. Thus, we searched for the involvement of other costimulatory molecules in EAM. We demonstrated the expression of inducible costimulator (ICOS)/ICOSL molecules in the lymph nodes, spleen, and heart in the EAM rat. We constructed adenovirus vectors containing ICOSIg (Adex1CAICOSIg) to achieve effective inhibition of ICOS/ICOSL interaction, and examined the effects of Adex1CAICOSIg on EAM. Adex1CAICOSIg treatment shortly after the immunization did not inhibit the onset and severity of EAM compared to control rats. On the other hand, delayed treatment with Adex1CAICOSIg significantly inhibited ongoing EAM. The survival rate in rats treated with Adex1CAICOSIg was significantly higher than that of the control group. Furthermore, the affected area ratio of the Adex1CAICOSIg treatment group was significantly lower than that of the control group. This study indicates that ICOS/ICOSL costimulation makes an important contribution to the progression of EAM and that the blockade of this pathway by gene transfer has therapeutic potential for ongoing autoimmune myocarditis.  相似文献   
46.
Abstract The present research investigated the prevalence of musculoskeletal disorders (MSD) among a previously understudied group of Asian nursing professionals in a rural setting. A total of 305 female nurses (84% response rate) were recruited from a university teaching hospital in Yamanashi prefecture, central Japan. Data were gathered by means of a self-reporting questionnaire. Lower back pain (LBP) was the most commonly reported MSD, affecting 59% of all nurses. This was followed by MSD of the shoulder (46.6%), neck (27.9%), knees (16.4%) and upper leg (11.8%). Working in the surgical department was shown to increase the risk of any MSD 2.7 times when compared to nurses in the other departments (odds ratio 2.7, 95% confidence interval 1.2–6.7, P = 0.0202). Overall, our study shows that MSD are reasonably common among registered nurses in a rural Japanese hospital. These staff may also be at greater risk of suffering MSD than their city-based nursing counterparts and foreign colleagues, particularly with respect to LBP.  相似文献   
47.
48.
Chronic infection with the protozoan parasite Trypanosoma cruzi is a major cause of morbidity and mortality in Latin America. Drug treatments for the associated illness, Chagas disease, are toxic and frequently unsuccessful. In a screening effort against the drug target protein farnesyltransferase, we identified a series of disubstituted imidazoles with highly potent anti-T. cruzi activity that apparently acted through a mechanism independent of protein farnesylation. Metabolic labeling studies of T. cruzi suggested that sterol biosynthesis was inhibited. Combined GC/MS analysis confirmed depletion of cellular sterols and suggested that the site of action was sterol 14-demethylase, a cytochrome P450 enzyme. Spectral studies with recombinant T. cruzi sterol 14-demethylase demonstrated that the compounds bind directly to this enzyme. Two of the compounds were well absorbed when given orally to mice, gave sustained plasma levels, and were well tolerated. The compounds were administered orally to mice with acute T. cruzi infection and caused dramatic decrease in parasitemia and led to 100% survival. These disubstituted imidazole compounds can be prepared by a relatively short synthetic route and represent a structural class with potent anti-T. cruzi activity.  相似文献   
49.
BACKGROUND: Serum alpha1-acid glycoprotein (AGP), an acute-phase protein secreted by the liver, carries alpha(1,3)-fucosylated structures on its 5 highly branched, N-linked sugar chains. METHODS: Serum AGP levels in patients with various types of malignancies (n=214 patients) were measured using an enzyme-linked immunosorbent assay with anti-AGP antibody. To investigate glycoforms that differed in their degree of branching and extent of fucosylation, serum AGP samples were analyzed by crossed affinoimmunoelectrophoresis (CAIE) with concanavalin A, and Aleuria aurantia lectin (AAL), and anti-AGP antibody. RESULTS: A significant difference (P <0.001) in serum AGP levels was observed in preoperative patients compared with levels in the healthy control group, but the levels in individual patients did not reflect their clinical status. Conversely, it was found not only that the patterns of AGP glycoforms differed widely in the patient group compared with the healthy control group, but they also changed depending on each patient's clinical status. Furthermore, AGP glycoforms seemed to be appropriate markers of disease progression and prognosis according to follow-up studies of 45 patients during prolonged preoperative and postoperative periods. CONCLUSIONS: Patients with advanced malignancies who had AGP glycoforms that contained highly fucosylated triantennary and tetraantennary sugar chains for long periods after surgery were likely to have a poor prognosis. However, patients who had AGP glycoforms without such changes were expected to have a good prognosis.  相似文献   
50.
Four new triterpenoids with various skeletons, maytefolins A-C (1-3) and uvaol-3-caffeate (4), were isolated from the leaves of a Brazilian medicinal plant, Maytenus ilicifolia, together with five known triterpenoids. Of these triterpenoids only erythrodiol exhibited significant cytotoxicity against KB/S, KB/VJ300, and KU 19-20 cells.  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