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   108075篇
  免费   6191篇
  国内免费   1646篇
耳鼻咽喉   715篇
儿科学   1444篇
妇产科学   1121篇
基础医学   11172篇
口腔科学   4587篇
临床医学   9904篇
内科学   18094篇
皮肤病学   1857篇
神经病学   7880篇
特种医学   3652篇
外国民族医学   5篇
外科学   16032篇
综合类   8294篇
现状与发展   5篇
一般理论   7篇
预防医学   8739篇
眼科学   1764篇
药学   12710篇
  56篇
中国医学   4404篇
肿瘤学   3470篇
  2023年   1244篇
  2022年   2041篇
  2021年   3856篇
  2020年   2838篇
  2019年   6560篇
  2018年   6885篇
  2017年   4912篇
  2016年   2307篇
  2015年   2386篇
  2014年   4209篇
  2013年   4662篇
  2012年   3737篇
  2011年   4272篇
  2010年   3503篇
  2009年   2908篇
  2008年   2986篇
  2007年   2975篇
  2006年   2641篇
  2005年   2178篇
  2004年   1959篇
  2003年   1766篇
  2002年   1432篇
  2001年   1248篇
  2000年   1116篇
  1999年   1034篇
  1998年   759篇
  1997年   768篇
  1996年   678篇
  1995年   693篇
  1994年   618篇
  1993年   538篇
  1992年   519篇
  1991年   510篇
  1990年   499篇
  1989年   446篇
  1988年   409篇
  1987年   365篇
  1985年   3204篇
  1984年   3736篇
  1983年   3118篇
  1982年   3652篇
  1981年   3281篇
  1980年   2759篇
  1979年   2688篇
  1978年   2186篇
  1977年   1690篇
  1976年   2119篇
  1975年   1606篇
  1974年   1391篇
  1973年   1334篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
《Cancer radiothérapie》2022,26(4):611-615
In order to provide more convenient irradiation regimens for patient comfort, radiation facility organization and health expenses, new hypofractionated protocols have been evaluated. Moderately (dose/fraction: 2.3 to 3 Gy), then ultra (dose/fraction: 5.2 to 6.1 Gy) hypofractionated irradiations were first validated. The current question is: is it possible to go forward using extreme hypofractionated regimens (EHR) based on 1 to 3 fractions. Different irradiation techniques are under investigation. However, brachytherapy remains the smartest way to deliver a high dose in a small volume. We report prospective and retrospective study results which evaluated EHR for breast and prostate brachytherapy. While oncological outcome and toxicity profile appear extremely encouraging for low-risk breast cancer after a 1 to 4 fractions (6.25 to 20 Gy/fraction), the use of a single fraction of 19 to 23 Gy appears debatable for prostate cancer. Brachytherapy represents an emblematic example of EHR but longer follow-up and more mature results are awaited in order to specify the right indications and refine the EQD2 calculation method including new biological and technical factors.  相似文献   
2.
3.
4.
When the COVID-19 pandemic hit, blood transfusion services worldwide started collection of convalescent plasma as early as possible, as exemplified by the response in Norway. There were challenges related to donor selection, donor safety, testing for relevant antibodies and indications for and dosing of the convalescent plasma. As more knowledge became available, the product quality was more standardised. Multiple case reports, observational studies and some randomized studies were published during the pandemic, as well as laboratory studies reporting different approaches to antibody testing. The results were conflicting and the importance of convalescent plasma was disputed.Even though there has been strong international collaboration with involvement of many key organisations, we may better prepare for the next pandemic. An even stronger, more formalised collaboration between these organisations could provide more clear evidence of the importance of convalescent plasma, based on the principles of passive immunisation.  相似文献   
5.
IntroductionEvidence for the relationship between movement behaviors and mental health among adolescents is inconclusive. We aimed to identify profiles of digital media use (including related bedtime delay) and leisure-time physical activity (LTPA) in adolescence, and to examine whether preadolescent mental health predicted later behavior profiles.MethodsThis study included 1285 participants assessed at 11 years of age, and followed-up four years later. Participants completed the Self-Perception Profile for Children (SPPC), Center for Epidemiological Studies Depression Scale for Children (CES-DC) and Screen for Child Anxiety-Related Emotional Disorders (SCARED) at baseline, and reported digital media use (active and passive use, gaming, and related bedtime delays) and LTPA at follow-up. A latent class approach was employed to identify behavior profiles, membership of which was then predicted with mental health and covariates, including baseline digital media use and LTPA.ResultsWe identified four behavior profiles: 1) high digital media use/moderate LTPA (20% of adolescents; 78% boys), 2) moderate digital media use/high LTPA (31%; 28%), 3) high digital media use/high LTPA (26%; 15%), 4) high passive digital media use and gaming/low LTPA (23%; 89%). After adjusting for covariates, higher LTPA and better perception of athletic competence at baseline associated with higher odds of belonging to any other profile than to the unhealthiest profile (4) at follow-up. Symptoms of depression or anxiety did not associate with later behavior profiles.ConclusionsLTPA and related self-esteem seem to be stronger predictors of future digital media use and LTPA behavior during adolescence than mental health symptoms alone.  相似文献   
6.
In this paper we present a coupled Finite Element Method – Boundary Element Method (FEM-BEM) approach for the solution of the free-boundary axi-symmetric plasma equilibrium problem. The proposed method, obtained from an improvement of the Hagenow-Lackner coupling method, allows to efficiently model the equilibrium problem in unbounded domains by discretizing only the plasma region; the external conductors can be modelled either as 2D or 3D models, according to the problem of interest. The paper explores different iterative methods for the solution of the nonlinear Grad-Shafranov equation, such as Picard, Newton-Raphson and Newton-Krylov, in order to provide a robust and reliable tool, able to handle large-scale problems (e.g. high resolution equilibria). This method has been implemented in the FRIDA code (FRee-boundary Integro-Differential Axisimmetric – https://github. om/matteobonotto/ FRIDA), together with a suitable Adaptive Integration Technique (AIT) for the computation of the source term. FRIDA has been successfully tested and validated against experimental data from RFX-mod device, and numerical equilibria of an ITER-like device.  相似文献   
7.
目的了解老年人生命晚期获知疾病相关信息意向及影响因素。方法2016年10月至2017年6月,采用生命晚期疾病信息意向问卷,利用方便抽样法对福州市中心城区7所养老机构及15个社区的414例年龄≥60岁的老年人进行横断面调查,采用单因素分析、多元线性回归与有序多分类logistic回归分析老年人对疾病相关信息的需求水平、获知程度意向及其影响因素。结果414例老年人疾病相关信息需求得分为(17.1±4.9)分;48.8%(202/414)希望详尽知晓,30.7%(127/414)希望选择性了解,20.5%(85/414)不想知道任何信息;多元线性回归分析显示,年龄、文化程度、是否接受/见过其他生命维持治疗(LSTs)是影响老年人疾病相关信息需求水平的主要因素(标准化回归系数分别为-0.141、0.116、0.115,均P<0.05);有序多分类logistic分析显示,年龄(以60~69岁为参照,70~79岁:OR=0.544,95%CI:0.310~0.957;80~89岁:OR=0.526,95%CI:0.289~0.956)、文化程度(以小学及以下为参照,大专及以上:OR=2.166,95%CI:1.093~4.290)、主要生活费来源(以其他补贴为参照,家人支持:OR=7.303,95%CI:1.157~46.108;退休金:OR=9.288,95%CI:1.502~57.415;公积金/储蓄:OR=15.676,95%CI:2.122~115.793)、是否接受/见过其他LSTs(以是为参照,OR=1.985,95%CI:1.150~3.425)是影响老年人疾病相关信息获知程度意向的主要因素。结论老年人生命晚期获知疾病相关信息的意向程度较高,年龄、文化程度、主要生活费来源、是否接受/见过其他生命维持治疗等是其主要影响因素。  相似文献   
8.
BackgroundDespite indications for the removal of temporary inferior vena cava (IVC) filters, many filters are unintentionally left in place, predisposing patients to adverse outcomes.ObjectiveThis quality improvement study set out to determine the impact of an IVC filter retrieval protocol on filter retrieval rates and patients lost to follow-up for patients who had undergone placement of a temporary IVC filter.MethodsFollowing a quasi-experimental design, data of all consecutive patients who underwent insertion of a temporary IVC filter for a period of 24-month preprotocol and 12-month postprotocol were compared.ResultsFilter retrieval rates of eligible filters increased from 64.2% to 100%; patients lost to follow-up decreased from 35.9% to 0% (p < .01, both outcomes).ConclusionAdoption of a comprehensive IVC filter protocol by the service that implants these devices can improve filter retrieval rates and decrease patients being lost to follow-up.  相似文献   
9.
10.
We review the spectrum of cutaneous disorders associated with inflammatory and neoplastic plasmacytic pathology. Because plasma cells are derived from B‐lymphocytes our overview includes discussion of certain lymphoplasmacytic proliferations. It is structured along histopathological lines, addressing conditions characterized by (a) cutaneous plasma cell infiltrates, (b) deposits of plasma cell products or their derivatives in the skin and (c) miscellaneous, poorly understood cutaneous complications of plasmacytic disorders. Lesions arising primarily in the skin and those due to cutaneous involvement by multisystem disorders are addressed. The range includes a spectrum of tumefactive and circulatory manifestations. We highlight key clinical and pathological features of the different conditions and outline recent advances in our understanding of these entities. By emphasizing the dermatopathological characteristics of this spectrum of disorders we hope to hone the diagnostic accuracy of practitioners in the field.  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