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   98383篇
  免费   9872篇
  国内免费   630篇
耳鼻咽喉   291篇
儿科学   2258篇
妇产科学   1755篇
基础医学   6459篇
口腔科学   4505篇
临床医学   18276篇
内科学   7666篇
皮肤病学   663篇
神经病学   6672篇
特种医学   974篇
外科学   3618篇
综合类   10836篇
现状与发展   4篇
一般理论   91篇
预防医学   37143篇
眼科学   351篇
药学   4136篇
  102篇
中国医学   1109篇
肿瘤学   1976篇
  2024年   90篇
  2023年   2725篇
  2022年   2455篇
  2021年   4775篇
  2020年   5444篇
  2019年   5073篇
  2018年   4470篇
  2017年   4297篇
  2016年   4158篇
  2015年   4093篇
  2014年   6743篇
  2013年   8808篇
  2012年   6033篇
  2011年   6563篇
  2010年   4933篇
  2009年   4905篇
  2008年   4875篇
  2007年   4876篇
  2006年   4193篇
  2005年   3215篇
  2004年   2742篇
  2003年   2360篇
  2002年   1716篇
  2001年   1651篇
  2000年   1406篇
  1999年   983篇
  1998年   771篇
  1997年   617篇
  1996年   498篇
  1995年   381篇
  1994年   377篇
  1993年   361篇
  1992年   290篇
  1991年   252篇
  1990年   214篇
  1989年   170篇
  1988年   195篇
  1987年   142篇
  1986年   119篇
  1985年   143篇
  1984年   109篇
  1983年   72篇
  1982年   76篇
  1981年   75篇
  1980年   77篇
  1979年   60篇
  1978年   55篇
  1977年   73篇
  1976年   55篇
  1975年   49篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
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   
3.
IntroductionOur aim was to describe practices in multimodal pain management at US children's hospitals and evaluate the association between non-opioid pain management strategies and pediatric patient-reported outcomes (PROs).MethodsData were collected as part of the 18-hospital ENhanced Recovery In CHildren Undergoing Surgery (ENRICH-US) clinical trial. Non-opioid pain management strategies included use of preoperative and postoperative non-opioid analgesics, regional anesthetic blocks, and a biobehavioral intervention. PROs included perioperative nervousness, pain-related functional disability, health-related quality of life (HRQoL). Associations were analyzed using multinomial logistic regression models.ResultsAmong 186 patients, 62 (33%) received preoperative analgesics, 186 (100%) postoperative analgesics, 81 (44%) regional anesthetic block, and 135 (73%) used a biobehavioral intervention. Patients were less likely to report worsened as compared to stable nervousness following regional anesthetic block (relative risk ratio [RRR]:0.31, 95% confidence interval [CI]:0.11–0.85), use of a biobehavioral technique (RRR:0.26, 95% CI:0.10–0.70), and both in combination (RRR:0.08, 95% CI:0.02–0.34). There were no associations of non-opioid pain control modalities with pain-related functional disability or HRQoL.ConclusionUse of postoperative non-opioid analgesics have been largely adopted, while preoperative non-opioid analgesics and regional anesthetic blocks are used less frequently. Regional anesthetic blocks and biobehavioral interventions may mitigate postoperative nervousness in children.Level of evidenceIII.  相似文献   
4.
5.
特纳综合征(TS)是女性常见的性染色体异常疾病,与多种疾病共存。越来越多的证据表明TS患者有较高的骨质疏松患病率,本文就近年来TS中骨质疏松的危险因素及管理治疗的相关研究进展做一综述。  相似文献   
6.
BackgroundDental caries is the most common chronic childhood disease. Past studies revealed that grandparents provide their grandchildren with cariogenic foods and beverages (eg, those with free sugars and/or modified starches). Qualitative research can help identify what drives this phenomenon.ObjectiveOur aim was to examine mothers’ explanations for why grandparents in north central and central Appalachia give their grandchildren cariogenic foods and beverages.DesignA qualitative study on children’s oral health in Pennsylvania and West Virginia from 2018 through 2020 was performed. In-person, semi-structured interviews were conducted. Qualitative data from interviews were recorded, transcribed, and then coded using NVivo. Data analysis for this study was performed using thematic analysis with iterative theme development.Participants/settingThe participants were 126 mothers of children aged 3-5 years from West Virginia (n = 66) and Pittsburgh, PA (n = 60).Main outcome measuresMothers’ perspectives about why grandparents give their grandchildren cariogenic foods and beverages were analyzed.ResultsIn the study sample, 85% of mothers (n = 107/126) named at least 1 of their children’s grandparents as a member of their social network responsible for their children’s oral health. From these interviews, 85% of mothers (n = 91/107) discussed that grandparents gave their grandchildren cariogenic foods and beverages. The mothers described the following 4 themes to explain why grandparents gave their grandchildren cariogenic foods and beverages: privilege of the grandparent role; responsibilities of the grandparent role; symbol of care and affection; and limited consideration or understanding of the detrimental impact.ConclusionsGrandparents play a role in giving their grandchildren cariogenic foods and beverages, which could potentially contribute to childhood caries. Research is needed to develop effective social interventions to help some grandparents understand the implications of a cariogenic diet on their grandchildren’s oral health and/or decrease their provision of cariogenic foods and beverages.  相似文献   
7.
The aim of this study was to examine if citizen science contributes to gaining insight into community health and to the health of the citizen scientists themselves. Therefore, thirteen citizens in four deprived neighbourhoods were trained as citizen scientists to conduct research in their own communities. Results showed that the citizen scientists identified forty (health related) themes in their communities. The citizen scientists reported an increase in their overall self-perceived health which, however, was not significantly demonstrated in the prequestionnaire and postquestionnaire.  相似文献   
8.
9.
The coronavirus disease 2019 pandemic presented challenges for urology patients to receive care in the format of a traditional clinic visit. For renal cancer patients, active surveillance and postintervention surveillance are the standard components of management. Telehealth, which was defined as a televideo encounter via the BlueJeans (Verizon) platform (a telehealth platform), was used to ensure continuity of care. Telehealth using the televideo modality was shown to be an effective model of care delivery to provide an optimal patient experience with ease of use.  相似文献   
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