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   1469篇
  免费   81篇
  国内免费   4篇
耳鼻咽喉   7篇
儿科学   87篇
妇产科学   22篇
基础医学   173篇
口腔科学   54篇
临床医学   62篇
内科学   225篇
皮肤病学   13篇
神经病学   153篇
特种医学   16篇
外科学   280篇
综合类   5篇
预防医学   190篇
眼科学   12篇
药学   74篇
肿瘤学   181篇
  2023年   9篇
  2022年   14篇
  2021年   23篇
  2020年   28篇
  2019年   26篇
  2018年   27篇
  2017年   21篇
  2016年   26篇
  2015年   27篇
  2014年   35篇
  2013年   57篇
  2012年   84篇
  2011年   86篇
  2010年   47篇
  2009年   45篇
  2008年   92篇
  2007年   86篇
  2006年   113篇
  2005年   88篇
  2004年   89篇
  2003年   93篇
  2002年   98篇
  2001年   23篇
  2000年   25篇
  1999年   24篇
  1998年   20篇
  1997年   19篇
  1996年   11篇
  1995年   15篇
  1994年   18篇
  1993年   11篇
  1992年   24篇
  1991年   14篇
  1990年   10篇
  1989年   13篇
  1988年   12篇
  1987年   5篇
  1986年   6篇
  1985年   10篇
  1984年   3篇
  1983年   8篇
  1982年   11篇
  1981年   5篇
  1980年   7篇
  1979年   5篇
  1977年   4篇
  1974年   3篇
  1972年   4篇
  1969年   4篇
  1966年   4篇
排序方式: 共有1554条查询结果,搜索用时 20 毫秒
901.
Because of increasing numbers of incident cancers and improving survival rates, more and more cancer patients are at risk of subsequent primary malignant neoplasms. The potential carcinogenicity of cancer therapies raises further concern regarding this unwanted long-term side effect. The objective of this cancer-registry-based study was to assess the trends in the risk of subsequent primary malignancies among cancer patients on a nationwide public-health level. The 470,000 cancer patients registered between 1953 and 1991 in Finland were followed up for subsequent primary neoplasms, and 19,800 subsequent malignant neoplasms were observed, yielding an overall standardized incidence ratio (SIR) of 1.00 for men and 1.25 for women. Substantial variation was observed in the SIR by the site of subsequent malignancy. The adjusted relative risk derived from multiple regression analyses showed only a slight increase by follow-up interval. Overall, the excess relative risk of subsequent malignancies was low, since the majority of cancer patients are old and at low relative risk. Patients under the age of 50 years, however, were at 70% increased risk, and the overall relative risk increased by 50% from the 1950s to the 1980s. Subsequent neoplasms among cancer patients do not pose a major public-health problem, but the possibility of subsequent cancers must be borne in mind in decisions concerning therapy and in clinical follow-up.  相似文献   
902.
ABSTRACT. The hepatic injury developing during occupational exposure to chemicals was investigated in 23 male patients, aged 23–49 years, by comparing case histories, liver function tests, hepatic microsomal enzyme activities in vivo and in vitro with histology. The subjects, 15 chemical industry workers and 8 painters, had disturbed liver tests after years of exposure to solvents, paints and lacquers. Characteristic for the patients was a 2–4-fold increase in serum aminotransferases associated with normal liver or reactive hepatitis with or without fatty liver. AU patients, except subjects with fatty change, had meta-bolically active liver which was reflected as adaptive and toxic changes in cellular ultrastructure. The biochemical liver tests normalized within 3–6 weeks after cessation of the exposure. The findings demonstrate that occupational exposure to chemical solvente may insidiously damage the liver. The injury is detectable by biochemical, metabolic and histological investigations in the early phase.  相似文献   
903.
Pharmacokinetics of ftorafur after intravenous and oral administration   总被引:1,自引:0,他引:1  
The pharmacokinetics of ftorafur (FT), an antineoplastic agent, has been studied in seven cancer patients by determining concentrations of the unchanged compound in serum after single IV and PO doses of 2 g FT. Serum drug concentrations were determined by a new quantitative thin-layer chromatographic method. After IV administration, the mean half-lives of the distribution phase and elimination phase were 1.0 h and 7.6 h, respectively. Total serum clearance was 69 ml/h . kg and the apparent volume of distribution was 0.66 l/kg. Following PO administration there was a short lag-time, 11 min, before the appearance of FT in peripheral serum, and the maximum concentration in peripheral serum was achieved in 3.2 h. Oral absorption was complete and no significant first-pass metabolism could be observed. FT elimination, measured in serum taken from the portal vein and a peripheral vein, occurred substantially at the same rate after IV and PO administration. In contrast, after the PO dose FT appeared in the portal serum significantly earlier than in the peripheral serum, resulting in a difference of 1.7 h in the time of maximum serum concentration. This indicates fast gastrointestinal absorption of FT but hepatic retention (without metabolism) before the appearance of FT in the peripheral serum.  相似文献   
904.
The effect of exogenous heparin on triton lipemia induced in rats was studied in 2 expts. 5×25 mg of Triton WR-1339 injected at intervals of 12 hrs caused an abrupt increase in the blood cholesterol and fat levels. They were both lowered distinctly by 50 IU of heparin injected concomitantly with triton. In the second experiment, 3×25 mg of triton provoked a smaller but significant elevation in the lipemia of rats. 3 × 250 IU of heparin nullified the hypercholesterinemia and the lipemia completely. Smaller doses of heparin caused a gradually diminishing inhibition of triton induced lipemia. The results of these two experiments and one of our earlier experiment suggest that Triton WR-1339 inhibits the release of heparin especially from the mucosal mast cells of gastrointestinal tract. Triton does not inhibit the activation of the clearing factor with exogenous heparin. Under these circumstances, it is possible to measure the shortage of endogenous heparin by replacing it with exogenous heparin using the level of lipemia as indicator.  相似文献   
905.
906.
STUDY OBJECTIVE: Mortality and morbidity vary across neighbourhoods and larger residential areas. Effects of area deprivation on health may vary across countries, because of greater spatial separation of people occupying high and low socioeconomic positions and differences in the provision of local services and facilities. Neighbourhood variations in health and the contribution of residents' characteristics and neighbourhood indicators were compared in London and Helsinki, two settings where inequality and welfare policies differ. DESIGN: Data from two cohorts were used to investigate associations between self rated health and neighbourhood indicators using a multilevel approach. SETTING: London and Helsinki. PARTICIPANTS: From the Whitehall II study (London, aged 39-63) and the Helsinki health study (aged 40-60). MAIN RESULTS: Socioeconomic segregation was higher in London than in Helsinki. Age and sex adjusted differences in self rated health between neighbourhoods were also greater in London. Independent of individual socioeconomic position, neighbourhood unemployment, proportion of residents in manual occupations, and proportion of single households were associated with health. In pooled data, residence in a neighbourhood with highest unemployment was associated with an odds ratio of less than good self rated health of 1.51 (95% CI 1.30 to 1.75). High rates of single parenthood were associated with health in London but not in Helsinki. CONCLUSIONS: Neighbourhood socioeconomic context was associated with health in both countries, with some evidence of greater neighbourhood effects in London. Greater socioeconomic segregation in London may have emergent effects at the neighbourhood level. Local and national social policies may reduce, or restrict, inequality and segregation between areas.  相似文献   
907.
OBJECTIVES: We examined the association of relative weight with individual income at different levels of socioeconomic status among gainfully employed Finnish women and men. METHODS: We used a population-based survey including 2068 women and 2314 men with linked income data from a taxation register. Regression analysis was used to calculate mean income levels within educational and occupational groups. RESULTS: Compared with their normal-weight counterparts, obese women with higher education or in upper white-collar positions had significantly lower income; a smaller income disadvantage was seen in overweight women with secondary education and in manual workers. Excess body weight was not associated with income disadvantages in men. CONCLUSIONS: Obesity is associated with a clear income disadvantage, particularly among women with higher socioeconomic status.  相似文献   
908.
OBJECTIVE: To examine socioeconomic differences in obesity using several different socioeconomic indicators, ranging from childhood socioeconomic environment and adult socioeconomic status to material resources and economic satisfaction. RESEARCH METHODS AND PROCEDURES: The data derived from the Helsinki Health Study baseline surveys in 2000 and 2001. Respondents to postal surveys were middle-aged employees of the City of Helsinki (4,975 women and 1,252 men, response rate 68%). Associations between eight socioeconomic indicators and obesity (BMI > or = 30 kg/m(2)), calculated from self-reported data, were examined by fitting a series of logistic regression models. RESULTS: In women, all socioeconomic indicators except household income and economic satisfaction were associated with obesity. Parental education and childhood economic difficulties, i.e., socioeconomic conditions in childhood, remained associated with obesity after adjusting for all indicators of current socioeconomic position. Indicators of adult socioeconomic status, own education and occupational class, were no longer associated with obesity when childhood socioeconomic conditions were adjusted for. Home ownership and economic difficulties were associated with obesity after full adjustments. In men, the findings paralleled those among women, but few associations reached statistical significance. DISCUSSION: Obesity was associated with several dimensions of socioeconomic position. Childhood socioeconomic disadvantage was associated with obesity independently of the various indicators of current socioeconomic position. Associations between obesity and both educational level and occupational class disappeared after adjustment for other indicators of socioeconomic position. This suggests that the variation observed in the prevalence of obesity by these key socioeconomic indicators may reflect differences in the related material resources.  相似文献   
909.
We explored the effect of a diagnosis of cancer on employment according to cancer type, education, occupation, age, gender, mother tongue (Swedish or Finnish), calendar time and hospital district. All 12,542 new cancer cases diagnosed in 1987-1988 and 1992-1993, aged 15-60 years at the time of the diagnosis were identified from the Finnish Cancer Registry. The employment rate of the cancer survivors 2-3 years after the diagnosis was only 9% lower than their gender- and age-matched referents. However, we found that education and occupation modified the effect of cancer on the employment; the difference between cancer survivors and their referents in the probability of being employed was greater in the lower than in the higher educational groups. A modifying effect of education on the probability of employment was found among people with cancer of the lung, stomach, rectum and cervix uteri and those with cancers of the nervous system.  相似文献   
910.
The IGF system is important in regulation of fetal and childhood growth. In later life, IGF-I and IGF-binding protein-1 (IGFBP-1) have been implicated in the pathogenesis of arteriosclerosis. They are, thus, potential candidates in explaining the link between early growth and adult cardiovascular disease. We measured fasting serum IGF-I and IGFBP-1 concentrations in 394 men and women from a cohort of 7086 individuals, born between 1924 and 1933 in Helsinki, Finland, whose weight and height were recorded at birth and from 7 to 15 yr of age. They also underwent clinical examination, including measurement of body fat using bioimpedance, blood pressure, glucose tolerance, and plasma insulin and fibrinogen concentrations. Serum IGF-I was positively correlated with fasting glucose (r = 0.10, P = 0.06) and fibrinogen (r = 0.19, P = 0.0001) concentrations and blood pressure (systolic and diastolic r = 0.10, P 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