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   101948篇
  免费   10009篇
  国内免费   203篇
耳鼻咽喉   1287篇
儿科学   3283篇
妇产科学   2477篇
基础医学   14474篇
口腔科学   2312篇
临床医学   12844篇
内科学   17911篇
皮肤病学   1565篇
神经病学   9154篇
特种医学   3036篇
外国民族医学   10篇
外科学   13040篇
综合类   1907篇
一般理论   111篇
预防医学   12075篇
眼科学   2219篇
药学   8105篇
  1篇
中国医学   104篇
肿瘤学   6245篇
  2021年   1404篇
  2020年   1075篇
  2019年   1653篇
  2018年   1951篇
  2017年   1455篇
  2016年   1546篇
  2015年   1744篇
  2014年   2389篇
  2013年   3643篇
  2012年   5011篇
  2011年   5339篇
  2010年   2849篇
  2009年   2733篇
  2008年   4529篇
  2007年   4993篇
  2006年   4853篇
  2005年   4825篇
  2004年   4559篇
  2003年   4211篇
  2002年   4066篇
  2001年   2862篇
  2000年   2924篇
  1999年   2585篇
  1998年   1153篇
  1997年   934篇
  1996年   904篇
  1995年   903篇
  1994年   899篇
  1993年   851篇
  1992年   2165篇
  1991年   2088篇
  1990年   1950篇
  1989年   1913篇
  1988年   1812篇
  1987年   1821篇
  1986年   1715篇
  1985年   1707篇
  1984年   1429篇
  1983年   1311篇
  1982年   903篇
  1981年   771篇
  1980年   694篇
  1979年   1249篇
  1978年   908篇
  1977年   794篇
  1976年   754篇
  1975年   743篇
  1974年   898篇
  1973年   793篇
  1972年   762篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Serrated polyps (SPs) are precursors to one-third of colorectal cancers (CRCs), with histological subtypes: hyperplastic polyps (HPs), sessile serrated lesions (SSLs) and traditional serrated adenomas (TSAs). The incidence of early-onset CRC before the age of 50 is increasing, with limited understanding of SPs in younger cohorts. Using a large colonoscopy-based cohort, we characterized epidemiologic profiles of SP subtypes, compared to conventional adenomas, with secondary analysis on early-onset polyps. Ninety-four thousand four hundred and twenty-seven patients underwent screening colonoscopies between 2010 and 2018. Demographic, endoscopic and histopathologic characteristics of each polyp subtype were described. High-risk polyps included SSLs ≥10 mm/with dysplasia and conventional adenomas ≥10 mm/with tubulovillous/villous histology/high-grade dysplasia. We examined polyp prevalence with age and compared early- (age < 50) and late-onset polyps (age ≥ 50). Eighteen thousand one hundred and twenty-five patients had SPs (4357 SSLs, 15 415 HPs, 120 TSAs) and 26 699 had conventional adenomas. High-risk SSLs were enriched in the ascending colon (44.1% vs 2.6-35.8% for other locations; P < .003). Early- and late-onset SPs had similar subsite distribution. Early-onset conventional adenomas were more enriched in the distal colon/rectum (51.8% vs 43.4%, P < .001). Multiple conventional adenomas were more represented in late-onset groups (40.8% vs 33.8%, P < .001), with no difference in SSLs. The prevalence of conventional adenomas/high-risk conventional adenomas increased continuously with age, whereas the prevalence of SSLs/high-risk SSLs was stable from age 40 years onwards. A higher proportion of women were diagnosed with early-onset than late-onset SSLs (62.9% vs 57.6%, P = .03). Conventional adenomas, SSLs, early- and late-onset polyps have distinct epidemiology. The findings have implications for improved colonoscopy screening and surveillance and understanding the etiologic heterogeneity of CRC.  相似文献   
2.
3.
4.
Isolated patellofemoral arthritis is an increasingly recognized entity, and is usually associated with previous patellofemoral dysplasia or instability. Patellofemoral arthroplasty (PFA) has evolved significantly in recent years, both in terms of implant design and importantly in the understanding of appropriate patient selection. This review outlines the indications and investigations for PFA, provides a brief history of the development of contemporary implants, and presents the clinical outcomes for the prostheses most commonly used in the UK. In addition, it provides a detailed surgical technique for implantation of an onlay implant, with tips on how to optimize patellofemoral biomechanics and thus achieve a consistently good outcome.  相似文献   
5.
6.
7.
8.
ObjectivesThe study aimed to identify changes in health literacy (HL) and associated variables during the first year following a kidney transplantation.MethodsA total of 196 transplant recipients were included in a prospective follow-up study. The patients answered the Health Literacy Questionnaire (HLQ) at 5 days, 8 weeks, 6 and 12 months following the kidney transplantation. Mixed linear models were used to analyze changes in HL and backward elimination was used to identify variables associated with HL.ResultsTwo main patterns of change were identified: a) HL increased during the first 8 weeks of close follow-up and b) in several domains, the positive increase from 5 days to 8 weeks flattened out from 5 days to 6 and 12 months. Self-efficacy, transplant-related knowledge, and general health were core variables associated with HL.ConclusionsOverall, HL increased during the 8 weeks of close follow-up following the kidney transplantation, while 6 months seem to be a more vulnerable phase. Furthermore, low self-efficacy, less knowledge, and low self-perceived health may represent vulnerable characteristics in patients.Practical implicationsFuture kidney transplant care should take into account patients’ access to and appraisal of health information and social support, and draw attention to potentially vulnerable groups.  相似文献   
9.
10.
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