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   18521篇
  免费   1763篇
  国内免费   26篇
耳鼻咽喉   241篇
儿科学   559篇
妇产科学   398篇
基础医学   2254篇
口腔科学   364篇
临床医学   2484篇
内科学   3564篇
皮肤病学   235篇
神经病学   1398篇
特种医学   837篇
外国民族医学   3篇
外科学   2416篇
综合类   488篇
一般理论   9篇
预防医学   1995篇
眼科学   599篇
药学   1500篇
  1篇
中国医学   13篇
肿瘤学   952篇
  2021年   315篇
  2020年   207篇
  2019年   294篇
  2018年   329篇
  2017年   205篇
  2016年   290篇
  2015年   307篇
  2014年   411篇
  2013年   586篇
  2012年   800篇
  2011年   873篇
  2010年   499篇
  2009年   426篇
  2008年   737篇
  2007年   841篇
  2006年   856篇
  2005年   784篇
  2004年   768篇
  2003年   692篇
  2002年   653篇
  2001年   573篇
  2000年   602篇
  1999年   531篇
  1998年   248篇
  1997年   233篇
  1996年   224篇
  1995年   203篇
  1994年   189篇
  1993年   170篇
  1992年   417篇
  1991年   422篇
  1990年   392篇
  1989年   419篇
  1988年   364篇
  1987年   337篇
  1986年   337篇
  1985年   319篇
  1984年   276篇
  1983年   237篇
  1982年   162篇
  1981年   129篇
  1979年   194篇
  1978年   170篇
  1977年   143篇
  1976年   132篇
  1974年   160篇
  1973年   144篇
  1972年   129篇
  1971年   116篇
  1969年   112篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
3.
Children who expect they can bring about good outcomes and avoid bad outcomes tend to experience more personal successes. Little is known about factors that contribute to these ‘control expectancies’. The purpose of the present study was to determine whether children's internal control expectancies occur in the context of parents’ internal control expectancies, low family strain, and high family cohesiveness and whether these factors are more strongly related to daughters’ than sons’ control expectancies. A community sample of 85 children aged 9–11 years and their parents (85 mothers; 63 fathers) completed rating scales. Fathers’ more internal control expectancies and mothers’ reports of fewer family strains were associated with daughters’ but not sons’ greater internal control expectancies, and greater family cohesiveness was related to both daughters’ and sons’ internal control orientations. These findings suggest that family factors may contribute to children's, particularly daughters’, development of internal control expectancies.  相似文献   
4.
5.
Journal of Neurology -  相似文献   
6.
7.
8.
Associations among dating, sexual activity, gender, and adjustment were investigated in 2,273 Italian adolescents (54% female, ages 14 to 19 years) attending public high schools. After controlling for age and type of school attended, both being in a dating relationship and being male were associated with less alienation, more positive views of the self, and higher general expectations for success. Sexual activity interacted with both gender and dating status in predicting feelings of depression. For boys, there were no differences between youth who were sexually active and youth who were not; however, sexually active girls had higher levels of depressive symptoms than girls who were not sexually active. Among youth who were not sexually active, there were small differences between daters and nondaters; among sexually active youth, daters had lower levels of depression than nondaters. Gender differences in adolescents' experience of dating and sexual relationships and implications for adjustment are discussed.  相似文献   
9.
BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is a rare malignant tumour of the skin, with an estimated incidence of 0.8 to five cases per 1 million people per year. OBJECTIVE: To study epidemiological, immunohistochemical and clinical features, delay in diagnosis, type of treatment and outcome of DFSP from 1982 to 2002. METHODS: Using data from the population-based cancer registry, 66 patients with pathologically proved DFSP were included (fibrosarcomatous DFSP were excluded). Each patient lived in one of the four departments of Franche-Comté (overall population of 1 million people) at the time of diagnosis. The main data sources came from public and private pathology laboratories and medical records. The rules of the International Agency for Research on Cancer were applied. RESULTS: The estimated incidence of DFSP in Franche-Comté was about three new cases per 1 million people per year. Male patients were affected 1.2 times as often as female patients were. The trunk (45%) followed by the proximal extremities (38%) were the most frequent locations. DFSP occurred mainly in young adults between 20 and 39 years of age. Mean age at diagnosis was 43 years, and the mean delay in diagnosis was 10.08 years. Our 66 patients initially underwent a radical local excision. Among them, 27% experienced one or more local recurrences during 9.6 years of follow-up. There was one regional lymph node recurrence without visceral metastases. These recurrences were significantly related to the initial peripheral resection margins. We observed a local recurrence rate of 47% for margins less than 3 cm, vs. only 7% for margins ranging from 3 to 5 cm [P=0.004; OR=0.229 (95%, CI=0.103-0.510)]. The mean time to a first local recurrence was 2.65 years. Nevertheless, there was no death due to the DFSP course at the end of the follow-up, and the final outcome was favourable. CONCLUSION: Our study emphasizes the importance of wide local excision with margins of at least 3 cm in order to prevent local recurrence. However, the recent development of inhibitors of signal transduction by the PDGFB pathway should soon modify the surgical strategy, which is often too mutilating.  相似文献   
10.
BACKGROUND: Until there is a definitive demonstration that early diagnosis and treatment of prostate cancer reduces disease-related mortality, it is imperative to promote informed screening decisions by providing balanced information about the potential benefits and risks of prostate cancer screening. Within a community/academic collaboration, we conducted a randomized trial of a printed booklet and a videotape that were designed for African American (AA) men. The purpose of the trial was to determine the effect of the interventions on knowledge, decisional conflict, satisfaction with the screening decision, and self-reported screening. METHODS: Participants were 238 AA men, ages 40 to 70 years, who were members of the Prince Hall Masons in Washington, DC. Men were randomly assigned to the (a) video-based information study arm, (b) print-based information study arm, or (c) wait list control study arm. Intervention materials were mailed to men at home. Assessments were conducted at baseline, 1 month, and 12 months postintervention. Multivariate analyses, including ANCOVA and logistic regression, were used to analyze group differences. RESULTS: The booklet and video resulted in a significant improvement in knowledge and a reduction in decisional conflict about prostate cancer screening, relative to the wait list control. Satisfaction with the screening decision was not affected by the interventions. Self-reported screening rates increased between the baseline and the 1-year assessment, although screening was not differentially associated with either of the interventions. In exploratory analyses, prostate-specific antigen testing at 1 year was more likely among previously screened men and was associated with having low baseline decisional conflict. CONCLUSIONS: This study represents one of the first randomized intervention trials specifically designed to address AA men's informed decision making about prostate cancer screening. We have developed and evaluated culturally sensitive, balanced, and disseminable materials that improved knowledge and reduced decisional conflict about prostate cancer screening among AA men. Due to the high incidence and mortality rates among AA men, there is a need for targeted educational materials, particularly materials that are balanced in terms of the benefits and risks of screening.  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