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   57401篇
  免费   4628篇
  国内免费   517篇
耳鼻咽喉   470篇
儿科学   2198篇
妇产科学   1578篇
基础医学   7538篇
口腔科学   594篇
临床医学   7738篇
内科学   10681篇
皮肤病学   835篇
神经病学   5300篇
特种医学   1296篇
外国民族医学   39篇
外科学   5448篇
综合类   1491篇
现状与发展   4篇
一般理论   100篇
预防医学   7695篇
眼科学   1087篇
药学   3602篇
  6篇
中国医学   467篇
肿瘤学   4379篇
  2024年   102篇
  2023年   625篇
  2022年   1032篇
  2021年   1908篇
  2020年   1219篇
  2019年   1707篇
  2018年   1934篇
  2017年   1465篇
  2016年   1519篇
  2015年   1760篇
  2014年   2316篇
  2013年   3212篇
  2012年   4542篇
  2011年   4666篇
  2010年   2555篇
  2009年   2128篇
  2008年   3815篇
  2007年   3716篇
  2006年   3480篇
  2005年   3406篇
  2004年   3026篇
  2003年   2703篇
  2002年   2537篇
  2001年   540篇
  2000年   408篇
  1999年   538篇
  1998年   550篇
  1997年   446篇
  1996年   391篇
  1995年   407篇
  1994年   314篇
  1993年   285篇
  1992年   248篇
  1991年   239篇
  1990年   208篇
  1989年   205篇
  1988年   178篇
  1987年   143篇
  1986年   149篇
  1985年   147篇
  1984年   156篇
  1983年   130篇
  1982年   138篇
  1981年   187篇
  1980年   130篇
  1979年   94篇
  1978年   79篇
  1977年   75篇
  1976年   63篇
  1974年   70篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
ABSTRACT

Adolescents and young adults smoke waterpipe tobacco (WT) and cigarillos, at least in part, based on erroneous beliefs that these products are safer than cigarettes. To address this challenge, we used a systematic, three-phase process to develop a health communication campaign to discourage WT and cigarillo smoking among at-risk (tobacco users and susceptible non-users) 16- to 25-year-olds. In Phase 1, we used a national phone survey (N = 896) to determine salient message beliefs. Participants reported constituents (i.e., harmful chemicals) emitted by the products were worrisome. In Phase 2, we developed and evaluated four message executions, with varying imagery, tone, and unappealing products with the same constituents, using focus groups (N = 38). Participants rated one execution highly, resulting in our development of a campaign where each message: (1) identified a tobacco product and constituent in the smoke; (2) included an image of an unappealing product containing the constituent (e.g., pesticides, gasoline) to grab attention; and (3) used a humorous sarcastic tone. In Phase 3, we tested the campaign messages (17 intervention and six control) with a nationally representative online survey (N = 1,636). Participants rated intervention and control messages highly with few differences between them. Exposure to messages resulted in significant increases in all risk beliefs from pre to post (< 0.05). For WT, intervention messages increased beliefs about addiction more than control messages (p < 0.05). This systematic, iterative approach resulted in messages that show promise for discouraging WT and cigarillo use.  相似文献   
33.
Background  Limited research exists on patient knowledge/cognition or “getting inside patients'' heads.” Because patients possess unique and privileged knowledge, clinicians need this information to make patient-centered and coordinated treatment planning decisions. To achieve patient-centered care, we characterize patient knowledge and contributions to the clinical information space. Methods and Objectives  In a theoretical overview, we explore the relevance of patient knowledge to care provision, apply historical perspectives of knowledge acquisition to patient knowledge, propose a representation of patient knowledge types across the continuum of care, and include illustrative vignettes about Mr. Jones. We highlight how the field of human factors (a core competency of health informatics) provides a perspective and methods for eliciting and characterizing patient knowledge. Conclusion  Patients play a vital role in the clinical information space by possessing and sharing unique knowledge relevant to the clinical picture. Without a patient''s contributions, the clinical picture of the patient is incomplete. A human factors perspective informs patient-centered care and health information technology solutions to support clinical information sharing.  相似文献   
34.
35.
36.
37.
38.
同步放化疗是不可手术局部晚期食管癌的标准治疗模式,国际推荐根治性放疗剂量为50.0~50.4Gy,但中国食管癌与西方国家在病理类型、生物学行为等方面大有不同,行根治性放疗剂量仍倾向于60Gy。增加放疗剂量能否带来生存获益成为临床亟待解决的问题。有研究认为高剂量放疗可提高局控率、改善生存,但也有研究认为提高剂量未能带来生存获益,且可增加不良反应事件发生率。因此,本文就食管癌根治性放疗剂量对预后的影响进行探讨,并通过放化疗后疗效评估对放疗剂量做出适当调整,以期达个体化放疗。  相似文献   
39.
The outbreaks of rabies in humans transmitted by Desmodus rotundus in 2004 and 2005, in the northeast of the Brazilian State of Para, eastern Amazon basin, made this a priority area for studies on this zoonosis. Given this, the present study provides data on this phenomenon in an urban context, in order to assess the possible circulation of the classic rabies virus (RABV) among bat species in Capanema, a town in the Amazon basin. Bats were collected, in 2011, with mist nets during the wet and dry seasons. Samples of brain tissue and blood were collected for virological and serological survey, respectively. None of the 153 brain tissue samples analyzed tested positive for RABV infection, but 50.34% (95% CI: 45.67-55.01%) of the serum samples analyzed were seropositive. Artibeus planirostris was the most common species, with a high percentage of seropositive individuals (52.46%, 95% CI: 52.31 52.60%). Statistically, equal proportions of seropositive results were obtained in the rainy and dry seasons (c2 = 0.057, d.f. = 1, p = 0.88). Significantly higher proportions of males (55.96%, 95% CI: 48.96-62.96%) and adults (52.37%, 95% CI: 47.35-57.39%) were seropositive. While none of the brain tissue samples tested positive for infection, the high proportion of seropositive specimens indicates that RABV may be widespread in this urban area.  相似文献   
40.

Background

We have recently shown that human epididymis protein 4 (HE4) levels correlate with the severity of cystic fibrosis (CF) lung disease. However, there are no data on how HE4 levels alter in patients receiving CFTR modulating therapy.

Methods

In this retrospective clinical study, 3 independent CF patient cohorts (US-American: 29, Australian: 12 and Irish: 19 cases) were enrolled carrying at least one Class III CFTR CF-causing mutation (p.Gly551Asp) and being treated with CFTR potentiator ivacaftor. Plasma HE4 was measured by immunoassay before treatment (baseline) and 1–6?months after commencement of ivacaftor, and were correlated with FEV1 (% predicted), sweat chloride, C-reactive protein (CRP) and body mass index (BMI).

Results

After 1?month of therapy, HE4 levels were significantly lower than at baseline and remained decreased up to 6?months. A significant inverse correlation between absolute and delta values of HE4 and FEV1 (r?=??0.5376; P?<?.001 and r?=??0.3285; P?<?.001), was retrospectively observed in pooled groups, including an independent association of HE4 with FEV1 by multiple regression analysis (β?=??0.57, P?=?.019). Substantial area under the receiver operating characteristic curve (ROC-AUC) value was determined for HE4 when 7% mean change of FEV1 (0.722 [95% CI 0.581–0.863]; P?=?.029) were used as classifier, especially in the first 2?months of treatment (0.806 [95% CI 0.665–0.947]; P?<?.001).

Conclusions

This study shows that plasma HE4 levels inversely correlate with lung function improvement in CF patients receiving ivacaftor. Overall, this potential biomarker may be of value for routine clinical and laboratory follow-up of CFTR modulating therapy.  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