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   3293篇
  免费   151篇
  国内免费   8篇
耳鼻咽喉   32篇
儿科学   100篇
妇产科学   52篇
基础医学   543篇
口腔科学   81篇
临床医学   198篇
内科学   705篇
皮肤病学   142篇
神经病学   325篇
特种医学   143篇
外科学   346篇
综合类   7篇
一般理论   1篇
预防医学   153篇
眼科学   43篇
药学   237篇
中国医学   4篇
肿瘤学   340篇
  2024年   4篇
  2023年   23篇
  2022年   35篇
  2021年   51篇
  2020年   38篇
  2019年   61篇
  2018年   66篇
  2017年   58篇
  2016年   61篇
  2015年   56篇
  2014年   94篇
  2013年   109篇
  2012年   212篇
  2011年   237篇
  2010年   142篇
  2009年   130篇
  2008年   216篇
  2007年   260篇
  2006年   234篇
  2005年   252篇
  2004年   201篇
  2003年   228篇
  2002年   214篇
  2001年   27篇
  2000年   25篇
  1999年   41篇
  1998年   59篇
  1997年   35篇
  1996年   35篇
  1995年   31篇
  1994年   22篇
  1993年   27篇
  1992年   17篇
  1991年   15篇
  1990年   18篇
  1989年   8篇
  1988年   6篇
  1987年   9篇
  1986年   6篇
  1985年   4篇
  1984年   7篇
  1982年   9篇
  1981年   10篇
  1980年   17篇
  1979年   8篇
  1978年   5篇
  1976年   5篇
  1975年   3篇
  1973年   3篇
  1972年   3篇
排序方式: 共有3452条查询结果,搜索用时 15 毫秒
101.
OBJECTIVE: To observe the trends and methods of tuberculosis (TB) detection in different occupations; to estimate the incidence of TB among nurses, and calculate the relative risk by comparing with the aged-matched general population; and to estimate the incidence of TB and relative risk also for teachers and doctors. MATERIALS AND METHODS: The background of TB patients was analyzed using the annual reports of TB registry for the period between 1987 and 2004. The population obtained from the national census, which was conducted every five years, was used for the calculation of TB incidence by specific occupation. The annual population between the two census years was obtained by interpolation. The TB registry assigns the same occupation code for nurses, public nurses and nursery teachers, and similarly assigns a common code for teachers and medical doctors. Therefore, TB incidence of nurses was calculated by subtracting the estimated number in nursery teachers. The number of nursery teachers contracting TB was obtained assuming that their TB incidence was the same as that for the 20-59 year-old population of the same sex. On the other hand, TB incidence for teachers and doctors was calculated together, because of the difficulties in separating the two occupations. RESULTS: Among nurses with TB, the proportion of cases detected by periodic mass screening in the workplace increased gradually from 21.4% in 1987 to 40.4% in 2004. Conversely, the proportion of cases detected by symptomatic vist to medical institutions declined from 69.4% in 1987 to 43.9% in 2004. In general population, the proportion of cases detected by contact tracing is low. Among nurses, however, cases detected by contact tracing had increased since around 1995 ; the proportion was 1-2% before 1995, increased to 7.0% in 1999 and leveled off at around 6-9%. TB incidence of female nurses declined slightly from 54.1 per 100,000 population in 1987 to 46.3 in 2004 (14.4%), and that of male nurses also declined from 127.0 in 1987 to 82.5 in 2004 (35.0%). However, the relative risk of female nurses increased from 2.1 (95%CI: 1.9-2.3) in 1987 to 4.3 (95% CI: 3.9-4.8) in 2004, and that of male nurses also increased from 2.4 (95%CI: 1.6-3.4) in 1987 to 3.8 (95%CI: 2.8-5.2) in 2004. The relative risk had increased gradually from the middle of 1990s in both sexes. TB incidence of female teachers and doctors decreased from 14.8 per 100,000 population in 1987 to 10.0 in 2004 (32.4%), and that of male teachers and doctors decreased from 39.3 in 1987 to 18.8 in 2004 (52.2%). While the relative risk was below 1 in both sexes, the relative risk in females increased from 0.6 (95%CI: 0.5-0.7) in 1987 to 0.8 (95% Cl: 0.7-1.1) in 2004, and that in males also increased from 0.7 (95%CI: 0.7-0.8) in 1987 to 0.9 (95%CI: 0.8-1.0) in 2004. CONCLUSION: Based on the relative risk data, approximately 80% of nurses with TB might have been infected by nosocomial infection and developed the disease. Since about half of them were detected in an early stage by mass screening in the workplace or contact tracing, TB control measures for nurses may be considered effective. However, the relative risk of TB among nurses had continued to increase without any trend of decline. The infection control at the hospitals may be inadequate, and should be reinforced by evaluating the methods or contents of control measures conducted so far.  相似文献   
102.
BACKGROUND: We are developing an immunotherapeutic peptide, Cry-consensus peptide, for Japanese cedar pollinosis. Cry-consensus peptide is a recombinant polypeptide containing six major human T-cell epitopes derived from both Cry j 1 and Cry j 2, two major allergens of Japanese cedar pollen. We examined the effect of Cry-consensus peptide on an allergic rhinitis model in B10.S mice, which have one common T-cell epitope in the Cry-consensus peptide. METHODS: B10.S mice were sensitized with Cry j 1/alum, then the Cry-consensus peptide was administered subcutaneously once a week for 5 weeks from the last sensitization. Histamine was dropped in both nostrils (10 microL per nostril) of each mouse on the day before continuous intranasal instillation of Cry j 1. Soon after the final challenge with Cry j 1, the mice were observed for 5 minutes for the resulting number of sneezes. In addition, serum levels of Cry j 1-specific IgE and IgG2a antibody, eosinophil infiltration in nasal tissue, and Cry j 1-specific cytokine production from splenocytes were evaluated. RESULTS: Cry-consensus peptide markedly inhibited Cry j 1-induced sneezes, eosinophil infiltration, and eosinophil peroxidase (EPO) activity in nasal tissue. Cry-consensus peptide inhibited the production of anti-Cry j 1 IgE (Th2-mediated) and significantly enhanced anti-Cry j 1 IgG2a (Th1-mediated). In cytokine production from splenocytes, Cry-consensus peptide significantly decreased in IL-4/IFN-gamma and IL-5/IFN-gamma ratios. CONCLUSIONS: It was concluded that Cry-consensus peptide effectively controlled allergic responses, which results from shifting from a Th2-dominated to a Th1-dominated immune response.  相似文献   
103.

Background  

Previous studies of magnetic resonance imaging (MRI) as a diagnostic tool for central nervous system (CNS) syndromes in systemic lupus erythematosus (SLE) contained several limitations such as study design, number of enrolled patients, and definition of CNS syndromes. We overcame these problems and statistically evaluated the diagnostic values of abnormal MRI signals and their chronological changes in CNS syndromes of SLE.  相似文献   
104.
PURPOSE: Recent studies have suggested a novel oncogenic role of a bric-a-brac tramtrack broad complex (also known as POZ) domain gene, NAC-1, in ovarian carcinomas. The aim of this study was to clarify the functional role of NAC-1 in human cervical carcinomas. EXPERIMENTAL DESIGN: NAC-1 expression in cervical cancer was assessed by immunohistochemistry, and data on clinical variables were collected by retrospective chart review. NAC-1 gene knockdown using small interfering RNA and a NAC-1 gene transfection system were used to asses NAC-1 function in cervical cancer in vivo. RESULTS: Immunohistochemical and gene expression analysis revealed that NAC-1 is significantly overexpressed in cervical adenocarcinomas and adenosquamous carcinomas compared with squamous cell carcinomas. Patients with squamous cell carcinomas positive for NAC-1 expression who received radiotherapy had significantly shorter overall survival than peers whose tumors did not express NAC-1, and multivariate analysis showed that NAC-1 expression was an independent prognostic factor for overall survival after radiotherapy. Overexpressions of the NAC-1 gene stimulated cell proliferation in cervical carcinoma cells of the TCS, CaSki, and HeLa P3 lines, which do not have endogenous NAC-1 expression. NAC-1 gene knockdown inhibited cell growth and induced apoptosis in HeLa, HeLa TG, and ME180 cells, all of which overexpressed NAC-1. CONCLUSIONS: Our findings suggest that NAC-1 may play an important role in cervical carcinomas; moreover, these findings provide a rationale for future development of NAC-1-based therapy for cervical carcinomas that overexpress this candidate oncogene.  相似文献   
105.
106.
目的 研究帕金森病痴呆(PDD)及路易体痴呆(DLB)的临床特征和病理学基础。方法 对9例有痴呆伴有帕金森病症状患者的临床特征和病理学进行分析。结果 9例中5例临床诊断为PDD,2例为帕金森病(PD),1例为进行性核上性麻痹(PSP)和1例阿尔茨海默病(AD)。5例PDD的病理亚型是新皮质型3例,边缘型2例。结论 本研究显示PDD与DLB有相似的病理学基础。  相似文献   
107.

Background  

Little is known about the HIV/AIDS epidemic in the Indian Ocean region, including Mauritius. National records suggest a prevalence of HIV in Mauritius of < 1% in the general population, which is one of the lowest prevalence rates in southern Africa. However, HIV-positive cases have been increasing recently in Mauritius. We conducted a cross-sectional survey in January 2003 to assess the prevalence of HIVrelated sexual behaviors and their correlates among young people aged 15–24 years in Mauritius.  相似文献   
108.
109.
The prevalence of BRCA1/2 germline mutations in Japanese patients suspected to have hereditary breast/ovarian cancer was examined by a multi‐institutional study, aiming at the clinical application of total sequencing analysis and validation of assay sensitivity in Japanese people using a cross‐sectional approach based on genetic factors estimated from personal and family histories. One hundred and thirty‐five subjects were referred to the genetic counseling clinics and enrolled in the study. Full sequencing analysis of the BRCA1/2 gene showed 28 types of deleterious mutations in 36 subjects (26.7%), including 13 types of BRCA1 mutations in 17 subjects (12.6%) and 15 types of BRCA2 mutations in 19 subjects (14.1%). Subjects were classified into five groups and 22 subgroups according to their personal and family history of breast and/or ovarian cancer, and the prevalence of deleterious mutations was compared with previously reported data in non‐Ashkenazi individuals. Statistical analysis using the Mantel‐Haenszel test for groups I through IV revealed that the prevalence of Japanese subjects was significantly higher than that of non‐Ashkenazi individuals (P = 0.005, odds ratio 1.87, 95% confidence interval 1.22–2.88). Family history of the probands suffering from breast cancer indicated risk factors for the presence of deleterious mutations of BRCA1/2 as follows: (1) families with breast cancer before age 40 within second degree relatives (P = 0.0265, odds ratio 2.833, 95% confidence interval 1.165–7.136) and (2) families with bilateral breast cancer and/or ovarian cancer within second degree relatives (P = 0.0151, odds ratio 2.88, 95% confidence interval 1.25–6.64). (Cancer Sci 2008; 99: 1967–1976)  相似文献   
110.
The interaction of interleukin-1 (IL-1) and interferon-γ (IFN-γ) actions on several aspects of angiogenesis in vitro and in vivo was studied. The proliferation and migration of human umbilical vein endothelial cells cultured with basic fibroblast growth factor (bFGF) were synergistically inhibited by cotreatment with IL-1 and IFN-γ. Endothelial cell adhesion to collagen was suppressed by IL-1 and the effect was slightly enhanced by the combination of IL-1 and IFN-γ. Local administration of IL-1 (10,000 U) and IFN-γ (1,000 U) inhibited bFGF-induced angiogenesis in the skin of mice, and synergistic inhibitory activity of the combination was demonstrated. Expression of FGF receptors was strongly downregulated by the combination, whereas expressions of epidermal growth factor (EGF) receptors, integrin β1 and integrin β3 were not. EGF partially abrogated the growth-inhibitory effects of IL-1 and IFN-γ. These findings indicate that IL-1 and IFN-γ are each able to act an angiogenesis inhibitor in a situation where FGF plays a major role in angiogenesis, and the activity is synergistically enhanced when they are used in combination.  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