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   50149篇
  免费   3987篇
  国内免费   794篇
耳鼻咽喉   203篇
儿科学   761篇
妇产科学   354篇
基础医学   5181篇
口腔科学   776篇
临床医学   5384篇
内科学   7202篇
皮肤病学   216篇
神经病学   5759篇
特种医学   1422篇
外国民族医学   2篇
外科学   3433篇
综合类   5326篇
现状与发展   4篇
一般理论   1篇
预防医学   8997篇
眼科学   380篇
药学   5081篇
  49篇
中国医学   2468篇
肿瘤学   1931篇
  2024年   153篇
  2023年   847篇
  2022年   1511篇
  2021年   2320篇
  2020年   2444篇
  2019年   1788篇
  2018年   1707篇
  2017年   1897篇
  2016年   1835篇
  2015年   1749篇
  2014年   4010篇
  2013年   4088篇
  2012年   3240篇
  2011年   3545篇
  2010年   2662篇
  2009年   2593篇
  2008年   2478篇
  2007年   2283篇
  2006年   1998篇
  2005年   1605篇
  2004年   1310篇
  2003年   1224篇
  2002年   989篇
  2001年   800篇
  2000年   617篇
  1999年   520篇
  1998年   440篇
  1997年   413篇
  1996年   362篇
  1995年   349篇
  1994年   284篇
  1993年   275篇
  1992年   230篇
  1991年   199篇
  1990年   233篇
  1989年   182篇
  1988年   197篇
  1987年   169篇
  1986年   165篇
  1985年   213篇
  1984年   173篇
  1983年   122篇
  1982年   134篇
  1981年   122篇
  1980年   108篇
  1979年   68篇
  1978年   56篇
  1977年   40篇
  1976年   57篇
  1975年   29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.
郭双辉  张玉梅 《中国全科医学》2022,25(12):1524-1528
认知功能障碍在肌萎缩侧索硬化(ALS)患者中是普遍存在的,ALS伴认知功能障碍常提示预后不良。近年来对ALS患者认知功能障碍的研究取得了一定的进展,本文对ALS伴认知功能障碍的临床特点、生物标志物、遗传学特征和最新治疗进展进行综述,以期为ALS伴认知功能障碍的临床诊疗提供新思路。  相似文献   
3.
4.

Background

Hyperglycaemia is common in patients with acute brain injury admitted to an intensive care unit (ICU). Many studies have found associations between development of hyperglycaemia and increased mortality in hospitalised patients. However, the optimal target for blood glucose control is unknown. We want to conduct a systematic review with meta-analysis and trial sequential analysis to explore the beneficial and harmful effects of restrictive versus liberal glucose control on patient outcomes in adults with severe acute brain injury.

Methods

We will systematically search medical databases including CENTRAL, Embase, MEDLINE and trial registries. We will search the following websites for ongoing or unpublished trials: http://www.controlled-trials.com/ , http://www.clinicaltrials.gov/ , www.eudraCT.com , http://centerwatch.com/ , The Cochrane Library's CENTRAL, PubMed, EMBASE, Science Citation Index Expanded and CINAHL. Two authors will independently review and select trials and extract data. We will include randomised trials comparing levels of glucose control in our analyses and observational studies will be included to address potential harms. The primary outcomes are defined as all-cause mortality, functional outcome and health-related quality of life. Secondary outcomes include serious adverse events including hypoglycaemia, length of ICU stay and duration of mechanical ventilation, and explorative outcomes including intracranial pressure and infection. Trial Sequential Analysis will be used to investigate the risk of type I error due to repetitive testing and to further explore imprecision. Quality of trials will be evaluated using the Cochrane Risk of Bias tool, and quality of evidence will be assessed using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach.

Discussion

The results of the systematic review will be disseminated through peer-reviewed publication. With the review, we hope to inform future randomised clinical trials and improve clinical practice.  相似文献   
5.
BackgroundRocker sole (RS) shoes have been linked to impaired postural control. However, which features of RS design affect balance is unclear.Research questionWhich RS design features affect standing balance and gait stability?MethodsThis study utilized an intervention and cross-over design. Twenty healthy young adults (10 males and 10 females) participated in this study. Standing balance and gait stability were measured using a single force platform and three-dimensional motion analysis system, respectively. The experimental conditions included the control shoe and five RS shoes in the combination of apex position (%) and apex angle (degree) for RS50-95, RS60-95, RS70-95, RS60-70, and RS60-110. The main outcome measures were the area surrounding the maximal rectangular amplitude, mean path length, average displacement of the center of pressure along the lateral and anterior/posterior directions, and maximal center of pressure excursion as the standing balance and lateral margin of stability as the gait stability. Statistical analyses were conducted using a two-way split-plot analysis of variance with repeated measures (with RS design as the within-subject factor and sex as the between-subject factor) and the Bonferroni post hoc test (α = .05).ResultsRegarding the mean path length, RS60-70 was significantly longer than the control shoe, and it showed a significantly increased lateral margin of stability. Thus, RS60-70 was shown to affect standing balance, limit of stability, and gait stability of the frontal plane during gait.SignificanceThese results suggest that the apex angle of the RS design feature affects standing balance and gait stability, and RS60-70 is detrimental to stability. Therefore, when RS with a small apex angle is prescribed, it is necessary to consider the patient’s balance ability.  相似文献   
6.
ObjectivesPrior evidence suggests that sleep duration and sleep difficulties may be associated with cognitive function in old age, but little is known about the sleep–cognition association in late mid-life. Our aim was to examine the associations of accelerometer-based sleep duration as well as subjective sleep difficulties with different domains of cognitive function among aging workers.MethodsThe study population consisted of 289 participants (mean age 62.4 years, SD 1.02; 83% women) from the Finnish Retirement and Aging Study (FIREA). Sleep difficulties were measured using Jenkins Sleep Problem Scale (difficulties falling asleep, difficulties maintaining sleep, waking up too early in the morning, and nonrestorative sleep). Sleep duration was measured with wrist-worn accelerometer and self-report, and participants were divided into short (<7 h/night), mid-range (7–9 h/night) and long (≥9 h/night) sleepers. Participants underwent extensive cognitive testing covering three domains: (1) memory, (2) executive function, and (3) attention and information processing.ResultsGreater difficulties in waking up too early in the morning were associated with poorer executive function measured with Spatial Working Memory (SWM) test (p = 0.005). Additionally, nonrestorative sleep was associated with poorer executive function measured with Trail Making Test, B–A, (p = 0.036) and borderline significantly with lower SWM (p = 0.056). Compared to mid-range sleepers, long sleepers tended to have poorer cognitive function (all memory function tests and SWM), but the associations were not statistically significant due to small number of long sleepers.ConclusionsSubjective sleep difficulties may be linked to poorer executive function in a relatively healthy population of older workers in their 60 s. Thus, promoting good sleep quality may translate into better cognitive health in late mid-life.  相似文献   
7.
目的探讨品管圈在植入式静脉输液港(IVAP)患者护理中的应用。方法选取本院2018年10月-2018年12月IVAP患者30例作为对照组,2019年1月-2019年3月品管圈活动干预后IVAP患者30例作为观察组。对照组采用常规护理措施,观察组采用品管圈活动干预后的护理措施。比较两组IVAP患者并发症的发生率和对护理工作的满意度。结果观察组导管堵塞1例;并发症发生率为3.33%(1/30)。对照组感染4例,血栓2例,导管堵塞4例;并发症发生率为33.33%(10/30)。观察组并发症发生率低于对照组(P <0.05)。观察组对优质服务、技术水平、关怀、出院指导、护理总满意度评分分别为(42.39±5.27)分、(31.49±4.32)分、(22.25±4.69)分、(20.26±4.91)分、(112.24±10.38)分;对照组分别为(38.65±4.91)分、(28.68±4.26)分、(19.96±4.30)分、(19.94±4.63)分、(103.37±10.12)分;观察组对优质服务、技术水平、关怀、出院指导、护理总满意度评分均高于对照组(P <0.05)。结论通过品管圈活动干预后的护理措施明显降低IVAP患者并发症的发生率,提高患者对护理工作的满意度。  相似文献   
8.
对当前的疾病预防控制体系和机构面临的体系不健全、政府投入不充分、事业发展不平衡、人才缺失和能力不足、缺乏系统的理论指导、体系的碎片化严重、与社会经济发展的战略衔接不力、机构内部内生动力和活力不足以及体系治理能力不足等问题做了讨论分析,以期进一步分析在健康中国战略和事业单位机构改革等宏观环境变化所带来的机遇以及疾控体系的发展策略和具体措施,促进疾病预防控制事业在改革中谋发展。  相似文献   
9.
Particle size analysis in the pharmaceutical industry has long been a source of debate regarding how best to define measurement accuracy; the degree to which the result of a measurement or calculation conforms to the true value. Defining a “true” value for the size of a particle can be challenging as the output of its measurement will differ because of variations in measurement approaches, instrumental differences and calculation methods. Consequently, for “real” particles, a universal “true” value does not exist and accuracy is therefore not a definable characteristic. Accordingly, precision is then a measure of the ability to reproducibly achieve a measurement of unknown relevance.This article proposes, in place of accuracy, a means to define the “appropriateness” of a measurement in line with the critical quality attributes (CQA) of the material being characterized. The decision as to whether the measurement is correct should involve a link to the CQA; that is, correlation should be demonstrated, without which the measured particle size cannot be defined as a critical material attribute.Correspondingly, methods should also be able to provide sufficient precision to demonstrate discrimination relating to variation in the CQA. The benefits and challenges of this approach are discussed.  相似文献   
10.
中药生产过程质量控制关键技术研究进展   总被引:10,自引:8,他引:2  
中医药发展已上升到国家战略层面,在医药行业贯彻实施"中国制造2025"战略的新形势下,中药生产过程质量控制是中药工业需要加快突破的关键领域之一。对中药生产过程质量控制领域在工艺设计、分析检测、过程建模、制造装备等方面的关键共性问题进行解析,综述了中药生产过程质量控制体系中工艺过程理解、生产过程实时分析方法开发、过程控制策略建立3个方面的研究进展;并结合企业研究实践,介绍了质量源于设计(quality by design,Qb D)、过程分析技术(process analytical technology,PAT)、实验设计(design of experiment,DOE)、多变量统计分析等关键技术在上述3个研究方向中的应用进展,分析了实际工业应用的难点问题并对其应用前景进行展望,旨在为中药企业应用和提升生产过程质量控制技术提供参考。  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