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   3934篇
  免费   322篇
  国内免费   10篇
耳鼻咽喉   55篇
儿科学   129篇
妇产科学   123篇
基础医学   442篇
口腔科学   292篇
临床医学   306篇
内科学   783篇
皮肤病学   67篇
神经病学   257篇
特种医学   237篇
外科学   481篇
综合类   20篇
一般理论   1篇
预防医学   602篇
眼科学   57篇
药学   274篇
中国医学   33篇
肿瘤学   107篇
  2023年   39篇
  2022年   72篇
  2021年   131篇
  2020年   86篇
  2019年   114篇
  2018年   151篇
  2017年   88篇
  2016年   118篇
  2015年   133篇
  2014年   203篇
  2013年   191篇
  2012年   253篇
  2011年   279篇
  2010年   205篇
  2009年   142篇
  2008年   228篇
  2007年   216篇
  2006年   184篇
  2005年   161篇
  2004年   148篇
  2003年   133篇
  2002年   96篇
  2001年   109篇
  2000年   87篇
  1999年   79篇
  1998年   39篇
  1997年   40篇
  1996年   38篇
  1995年   28篇
  1994年   15篇
  1993年   17篇
  1992年   34篇
  1991年   30篇
  1990年   41篇
  1989年   40篇
  1988年   30篇
  1987年   38篇
  1986年   26篇
  1985年   33篇
  1984年   20篇
  1983年   8篇
  1982年   9篇
  1980年   13篇
  1979年   13篇
  1978年   16篇
  1977年   9篇
  1976年   7篇
  1975年   10篇
  1970年   8篇
  1967年   8篇
排序方式: 共有4266条查询结果,搜索用时 812 毫秒
981.
OBJECTIVE: To estimate the prevalence of alcohol abuse/dependence and identify associated factors among demographic, family, socioeconomic and mental health variables. METHODS: A household survey was carried out in the urban area of Campinas, southeastern Brazil, in 2003. A total of 515 subjects, aged 14 years or more were randomly selected using a stratified cluster sample. The Self-Report Questionnaire and the Alcohol Use Disorder Identification Test were used in the interview. Prevalences were calculated, and univariate and multivariate logistic analyses performed by estimating odds ratios and 95% confidence intervals. RESULTS: The estimated prevalence of alcohol abuse/dependence was 13.1% (95% CI: 8.4;19.9) in men and 4.1% (95% CI: 1.9;8.6) in women. In the final multiple logistic regression model, alcohol abuse/dependence was significantly associated with age, income, schooling, religion and illicit drug use. The adjusted odds ratios were significantly higher in following variables: income between 2,501 and 10,000 dollars (OR=10.29); income above 10,000 dollars (OR=10.20); less than 12 years of schooling (OR=13.42); no religion (OR=9.16) or religion other than Evangelical (OR=4.77); and illicit drug use during lifetime (OR=4.47). Alcohol abuse and dependence patterns were different according to age group. CONCLUSIONS: There is a significantly high prevalence of alcohol abuse/dependence in this population. The knowledge of factors associated with alcohol abuse, and differences in consumption patterns should be taken into account in the development of harm reduction strategies.  相似文献   
982.
983.
984.
The article presents prevalence rates for malnutrition, intestinal parasitic infections, anemia, and iron deficiency in under-five children in a population-based cross-sectional survey performed in the urban area of two counties in the Western Brazilian Amazon, Assis Brasil (n = 200) and Acrelandia (n = 477). Available data included: (a) weight and height measurements, standardized as z-scores using the 1977 NCHS reference population, (b) diagnosis of current intestinal parasitic infection, (c) blood hemoglobin levels, and (d) plasma ferritin and soluble transferrin receptor levels. Overall prevalence rates of low weight-for-height, low weight-for-age, and low height-for-age were 3.7%, 8.7%, and 7.5%, respectively, with similar figures in the two towns. Intestinal parasites were detected in 32.5% children; helminths were uncommon. Anemia and iron deficiency were diagnosed in 30.6% and 43.5% of the children, respectively. Evidence of anemia was found in only 47.6% of the children with depleted iron reserves, indicating that hemoglobin measurement alone would severely underestimate the magnitude of iron deficiency in this population. In both towns, anemia and malnutrition were significantly more prevalent among children in the lowest socioeconomic stratum.  相似文献   
985.
The number of AIDS cases in men who have sex with men (MSM) decreased in the initial years of the epidemic, but the percentage of cases in this group has remained unaltered in the last five years. This study, aimed to improve knowledge on the impact of AIDS in the daily lives of MSM, was conducted in Campo Grande, Mato Grosso do Sul State, Brazil, using a questionnaire and interviews. The results show that MSM perceive their vulnerability to HIV infection, referring to inconsistent condom use and multiple sex partners, given that 65% of homosexuals, 75% of bisexuals, and 33% of transvestites reported up to 5 partners in the previous month and emphasizing that 59% of the group reported more than 11 partners during the same period. The susceptibility of certain groups and the identification and understanding of their specificities pose a major challenge in any geographic context where such conditions are present.  相似文献   
986.
The objective of this study was to assess Mini-Mental State Examination norms of a functionally normal sample of community-dwelling elderly. Illiterate and low-educated subjects who scored less than 5 on the Pfeffer Functional Activities Questionnaire (PFAQ) [n = 397; female = 269; mean age = 72.15 (SD = 7.24) years] had the 5th, 25th, 50th, and 75th percentiles calculated according to age (65-74; 75-84 years). Overall MMSE score was 21.97 (SD = 4.48). Mean MMSE for illiterate younger individuals was 19.46 (SD = 3.47), and the quartile distribution was 14, 17, 19, and 21. MMSE of subjects with 1-8 years of schooling was 23.90 (3.87), and the distribution was 15, 22, 24, and 27. MMSE of older illiterate subjects was 18.11 (SD = 3.63), and the distribution of scores was 13, 16, 18, and 20, whereas subjects with 1-8 years of schooling scored 23.81 (SD = 4.01) and the distribution was 15, 22, 24, and 27. These MMSE normative data may help improve the detection of cognitive impairment in Brazil, mainly in the primary clinical setting.  相似文献   
987.
The aim of this study was to evaluate the Edinburgh Postnatal Depression Scale (EPDS) for screening and diagnosis of postpartum depression. Three months after delivery, EPDS was administered to 378 mothers from the 2004 Pelotas Birth Cohort Study, Rio Grande do Sul State, Brazil. Up to 15 days later, mothers were re-interviewed by mental health care professionals using a semi-structured interview based on ICD-10 (gold standard). We calculated the sensitivity and specificity of each cutoff point, and values were plotted as a receiver operator characteristic curve. The best cutoff point for screening postpartum depression was > 10, with 82.6% (75.3-89.9%) sensitivity and 65.4% (59.8-71.1%) specificity. For screening moderate and severe cases, the best cutoff point was > 11, with 83.8% (73.4-91.3%) sensitivity and 74.7% (69.4-79.5%) specificity. For diagnosis, EPDS was valid only for prevalence of postpartum depression in the 20-25% range, with 60% PPV for the > 13 cutoff point (59.5% sensitivity; 88.4% specificity). The specificities and PPVs for all cutoff points were below those reported by other authors. Small numbers and the calculation of PPV in samples with overrepresentation of cases in the majority of studies appear to account for these differences.  相似文献   
988.
AIMS: With the purpose of studying left ventricular filling in Chagas' disease (Chd), we evaluated 169 patients with Chd using echocardiography and Doppler and tissue Doppler imaging (TDI). METHODS AND RESULTS: The patients were divided into four groups according to the pattern of left ventricular filling: Group 0--normal filling pattern, Group 1--abnormal relaxation, Group 2--pseudonormal flow pattern, and Group 3--restrictive pattern. All patients were submitted to TDI of the basal portion of the left ventricle's walls. Diastolic dysfunction was found in 21.3% of the patients, with a strong correlation between the worsening of diastolic function and ejection fraction (r = 0.78, P < 0.001). TDI septal e' wave measurement was the best method for the detection of any kind of diastolic dysfunction. Considering a cut-off point of 11 cm/s, a reduced e' wave value has 97% sensitivity, 84% specificity, 62% positive predictive value, and 99% negative predictive value. The septal E/e' ratio was the best index for the detection of advanced diastolic dysfunction. Considering a cut-point of 7.2, an elevated E/e' ratio has 100% sensitivity, 88% specificity, 54.2% positive predictive value, and 100% negative predictive value. CONCLUSION: This study showed the characterization of the various patterns of left ventricle diastolic function by echocardiography and Doppler in Chagas' disease and the usefulness of TDI in the assessment of diagnosis of diastolic dysfunction in this disease.  相似文献   
989.
990.
A BamHI polymorphism has been identified in the human factor IX gene. This polymorphism, which occurs in approximately 6% of X chromosomes, has been used to determine the carrier status of a female in a family with a history of hemophilia B. This family was uninformative for the previously reported TaqI and Xmnl polymorphisms in the factor IX gene.  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