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   1122篇
  免费   40篇
  国内免费   14篇
耳鼻咽喉   1篇
儿科学   33篇
妇产科学   32篇
基础医学   113篇
口腔科学   7篇
临床医学   173篇
内科学   229篇
皮肤病学   33篇
神经病学   86篇
特种医学   30篇
外科学   74篇
综合类   169篇
预防医学   66篇
眼科学   26篇
药学   57篇
中国医学   3篇
肿瘤学   44篇
  2023年   12篇
  2022年   37篇
  2021年   22篇
  2020年   21篇
  2019年   17篇
  2018年   26篇
  2017年   23篇
  2016年   21篇
  2015年   33篇
  2014年   67篇
  2013年   63篇
  2012年   40篇
  2011年   60篇
  2010年   42篇
  2009年   45篇
  2008年   64篇
  2007年   49篇
  2006年   43篇
  2005年   50篇
  2004年   44篇
  2003年   34篇
  2002年   37篇
  2001年   30篇
  2000年   28篇
  1999年   26篇
  1998年   26篇
  1997年   18篇
  1996年   16篇
  1995年   19篇
  1994年   15篇
  1993年   13篇
  1992年   14篇
  1991年   16篇
  1990年   14篇
  1989年   12篇
  1988年   11篇
  1987年   7篇
  1986年   3篇
  1985年   7篇
  1984年   11篇
  1983年   9篇
  1982年   2篇
  1981年   4篇
  1980年   10篇
  1979年   5篇
  1978年   3篇
  1976年   2篇
  1975年   1篇
  1972年   2篇
  1971年   1篇
排序方式: 共有1176条查询结果,搜索用时 15 毫秒
1.
2.
3.
目的 探讨脑囊虫病患者各期脑脊液中的一氧化氮 (NO)、肿瘤坏死因子α(TNF α)的变化规律及它们在脑囊虫病中的作用机制。方法 检测 4 9例明确诊断并依据MR分期 ,单发脑实质内囊虫的脑囊虫病患者和 2 0名对照者脑脊液中NO、TNF α水平。结果 NO在脑囊虫病的Ⅰ期显著降低而TNF α水平呈显著升高 ,NO、TNF α于Ⅱ期、Ⅲ期 (整个退变死亡期 )均表现为高水平 ,Ⅳ期恢复正常 ,NO和TNF α存在高度正相关关系。结论 在单发脑实质内囊虫病中NO、TNF α可能参与杀虫作用 ,其免疫调节与杀虫机制存在着动态平衡 ,参与感染控制  相似文献   
4.
脑囊虫病人血清、脑脊液中抗体在MRI各期的变化   总被引:1,自引:0,他引:1  
目的 检测脑囊虫病人血清和脑脊液中抗体在MRI各期的变化。方法 用抑制性ELISA法检测血清及脑脊液中的抗体。同时根据MRI表现将病例分为活动期、退变期、非活动期。结果 在69个病例中,脑脊液中抗体阳性率分别是:活动期75.00%,退变期62.50%,非活动期17.24%;血清中是81.25%、16.67%、22.22%。在相应各期中,脑脊液和血清抗体阳性率无显著性差别。结论 在影像学的不同时期抗体阳性率存在明显的变化。  相似文献   
5.
Introduction Postoperative treatment for colorectal cancer depends on tumor stage as defined by the International Union Against Cancer (UICC). Adjuvant chemotherapy is not recommended in patients without lymph node involvement (UICC stages I and II). As many as 20–30% of these patients, however, will develop recurrence. Aims and objectives We conducted this study to determine the presence of disseminated tumor cells in the lymph nodes by quantitative real-time polymerase chain reaction (QRT-PCR) for cytokeratin 20 (CK20) in an attempt to provide supplementary information compared to histopathological findings. Materials and methods Using a standard QRT-PCR assay, we examined primary tumors and 391 lymph nodes from 31 patients with completely resected colorectal cancer. Results Of the 31 primary tumors, 29 were positive for CK20 by QRT-PCR. Discussion An examination of the lymph nodes from the 29 patients with CK20-positive primary tumors revealed that 35 (92.1% sensitivity) of the 38 histopathologically positive lymph nodes and 54 (16.7%) of the 324 histopathologically negative lymph nodes were positive by molecular analysis. CK20 expression was detected in 10 (100%) of 10 patients with a histopathologically positive lymph node status (pN1). In 9 (47.4%) of 19 patients with negative histopathological results (pN0), we detected a CK20 mRNA signal in at least one lymph node. Whereas eight patients with histopathologically negative lymph nodes could be upstaged on the basis of the molecular findings, no patient would be downstaged. Conclusion Our results suggest that QRT-PCR for CK20 is a useful tool for the quantitative detection of micrometastases in the regional lymph nodes. We introduce a standardized procedure that integrates a molecular diagnostic technique in the clinical staging.  相似文献   
6.
Summary Excessive bleeding frequently complicates the care of critically-ill patients. Except in the case of trauma or in patients with known coagulopathies (e.g., hemophilia), the bleeding is generally not directly related to the illness that results in admission to the intensive care unit. In general, the causes of the bleeding can be divided into 3 categories: consumptive coagulopathies (e.g., DIC), bleeding related to ``hepatic issues' (i.e., liver dysfunction, vitamin K deficiency), and iatrogenic causes. This review will discuss the more common causes of bleeding in the critically-ill patient and outline diagnostic and treatment approaches for these patients. New experimental data linking activation of the coagulation and inflammatory systems with the development of multisystem organ failure is briefly discussed. Received: 8 November 1996 Accepted: 18 November 1996  相似文献   
7.
应用抗猪囊虫抗原的单克隆抗体反向间接血凝试验(IHAT),对临床确诊的囊虫病患者进行了血清循环抗原(CAg)的检测,阳性率为51.14%(67/131)。对19例脑型囊虫病患者同时测定了血清和脑脊液中的CAg,阳性率分别为47.36%和78.94%,总阳性率为84.21%。对治疗0.53后的19例患者检测时,血清和脑脊液中CAg均呈阴性反应,而检测抗体仍呈阳性反应。50例正常人、49例其它寄生虫病及5例其它脑部疾病患者脑脊液的CAg均呈阴性反应。结果提示:测定CAg对囊虫病活动性感染的诊断及疗效判定均具有一定的实用价值。  相似文献   
8.
Patients with liver failure can present both thrombotic and hemorragic complications because of the deficiency in coagulation factors and inhibitors (protein C and S, antithrombin III) and impairment of fibrinolytic balance. Here we report the case of a 63-year-old man with liver cirrhosis, recurrent thrombosis, and features of low-grade consumption coagulopathy, showing severe antithrombin III deficiency (about 30% of normal values). Treatment with antithrombin III (2000 U/day) and low doses of heparin (5000 U b.i.d.) was successful in modulating the coagulation system toward an antithrombotic effect. After discharge from hospital the ambulatory treatment with antithrombin III concentrates (2000 U twice a week) allowed the attainment of antithrombin III activity of about 60% and prevented the patient from recurrence of venous thrombosis.Abbreviations AT-III Antithrombin III - DIC Disseminated intravascular coagulation - TAT complexes Thrombin-antithrombin III complexes - PAI-1 Plasminogen activator inhibitor-1  相似文献   
9.
Different polymorphisms have been described in the minimal promoter region (MPR) of the interferon-gamma receptor 1 (IFNGR1), a molecule that plays a critical role in mycobacterial control. We sequenced the IFNGR1 MPR from African American, Caucasian and Korean controls, and from mycobacteria-infected patients. Six different single nucleotide polymorphisms (SNPs) were detected in the IFNGR1 MPR. The three ethnic groups showed different SNP distribution patterns, but no significant differences were detected between mycobacterial cases and controls. Two polymorphisms were found in all populations (G-611A, T-56C). We cloned the four allelic variants (var) of haplotype G-611A/T-56C into a luciferase reporter vector and determined their promoter activity. Polymorphisms at position -611 had a stronger effect on the promoter activity than those at position -56, and constructs carrying G-611 produced a stronger promoter activity than -611A constructs. The IFNGR1 MPR is a polymorphic region with at least two SNPs influencing its activity, but these are not associated with increased mycobacterial susceptibility.  相似文献   
10.
Histoplasma infections in Europe are rare, and acute disseminated histoplasmosis has only been observed in immunocompromised persons. We describe a case of acute disseminated histoplasmosis in a young, nonimmunocompromised European woman. The probable source of infection was Sri Lanka or the Maldives. At presentation she was severely ill with fever, lymphadenopathy, anemia, thrombocytopenia, hepatosplenomegaly, and polyserositis. Histologically, myelofibrosis and osteosclerosis were observed with extramedullary hematopoiesis. Histoplasma capsulatum yeasts were detected in bone marrow trephine biopsy by methenamine silver staining. Treatment with conventional and liposomal amphotericin B and subsequent itraconazole led to rapid and complete recovery.Abbreviations He Histoplasma capsulatum - AIDS acquired immunodeficiency syndrome - HIV human immunodeficiency virus  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