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   4614992篇
  免费   341067篇
  国内免费   126746篇
耳鼻咽喉   48871篇
儿科学   110255篇
妇产科学   79711篇
基础医学   483682篇
口腔科学   117907篇
临床医学   476319篇
内科学   623408篇
皮肤病学   71866篇
神经病学   329366篇
特种医学   157462篇
外国民族医学   714篇
外科学   498362篇
综合类   637806篇
现状与发展   363篇
一般理论   376篇
预防医学   418668篇
眼科学   84581篇
药学   488450篇
  3090篇
中国医学   204062篇
肿瘤学   247486篇
  2024年   10253篇
  2023年   64437篇
  2022年   126781篇
  2021年   167740篇
  2020年   154868篇
  2019年   140419篇
  2018年   141317篇
  2017年   145190篇
  2016年   153331篇
  2015年   158903篇
  2014年   288328篇
  2013年   338291篇
  2012年   261950篇
  2011年   298677篇
  2010年   241267篇
  2009年   237045篇
  2008年   235314篇
  2007年   232100篇
  2006年   209838篇
  2005年   180481篇
  2004年   151938篇
  2003年   130829篇
  2002年   105108篇
  2001年   93788篇
  2000年   77761篇
  1999年   66374篇
  1998年   62093篇
  1997年   57537篇
  1996年   53026篇
  1995年   48491篇
  1994年   43535篇
  1993年   36547篇
  1992年   34060篇
  1991年   30505篇
  1990年   26909篇
  1989年   24225篇
  1988年   22831篇
  1987年   20026篇
  1986年   18302篇
  1985年   26978篇
  1984年   25869篇
  1983年   17720篇
  1982年   20829篇
  1981年   18303篇
  1980年   16103篇
  1979年   13763篇
  1978年   11494篇
  1977年   9160篇
  1976年   8805篇
  1975年   6017篇
排序方式: 共有10000条查询结果,搜索用时 31 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.

Objective

The aim of the study was to estimate the effect of the state-based reinsurance programs through the section 1332 State Innovation Waivers on health insurance marketplace premiums and insurer participation.

Data Source

2015 to 2022 Robert Wood Johnson Foundation Health Insurance Exchange Compare Datasets.

Study Design

An event study difference-in-differences (DD) model separately for each year of implementation and a synthetic control method (SCM) are used to estimate year-by-year effects following program implementation.

Data Collection/Extraction Methods

Not applicable.

Principal Findings

Reinsurance programs were associated with a decline in premiums in the first year of implementation by 10%–13%, 5%–19%, and 11%–17% for bronze, silver, and gold plans (p < 0.05). There is a trend of sustained declines especially for states that implemented their programs in 2019 and 2020. The SCM analyses suggest some effect heterogeneity across states but also premium declines across most states. There is no evidence that reinsurance programs affected insurer participation.

Conclusion

State-based reinsurance programs have the potential to improve the affordability of health insurance coverage. However, reinsurance programs do not appear to have had an effect on insurer participation, highlighting the need for policy makers to consider complementary strategies to encourage insurer participation.  相似文献   
3.
4.
目的 系统评价翻转课堂教学模式在物理治疗学教学中的应用效果。方法 计算机检索CENTRAL、MEDLINE、EMBASE、CINAHL Plus、Academic Search Premier、Teacher Reference Center、ERIC以及Education Research,纳入翻转课堂教学模式应用于物理治疗学教学的原始研究。检索时限为建库至2021年6月。由2名研究人员独立完成文献筛选、数据提取、质量评价,对翻转课堂教学模式对比传统教学模式在物理治疗学教学中的效果进行综述。结果与结论 共检索文献1 307篇,最终纳入7篇,包括至少770名学生。发表时间集中在2013年至2019年,研究对象为物理治疗学专业学生,主要结局指标为考试成绩。翻转课堂教学模式总体说来可提高学生的笔试成绩,增强高阶思维能力,得到了学生和教师的积极评价。  相似文献   
5.
BackgroundVoices for Food was a longitudinal community, food pantry–based intervention informed by the social ecological model, and designed to improve food security, dietary intake, and quality among clients, which was carried out in 24 rural food pantries across 6 Midwestern states.ObjectiveOur objective was to evaluate changes in adult food security, dietary intake, and quality from baseline (2014) to follow-up (2016), and to assess the role of adult food security on dietary outcomes.DesignA multistate, longitudinal, quasi-experimental intervention with matched treatment and comparison design was used to evaluate treatment vs comparison group changes over time and changes in both groups over time.Participants/settingAdult food pantry clients (n = 617) completed a demographic food security survey, and up to three 24-hour dietary recalls at baseline (n = 590) and follow-up (n = 160).InterventionCommunity coaching served as the experimental component, which only “treatment” communities received, and a food council guide and food pantry toolkit were provided to both “treatment” and matched “comparison” communities.Main outcome measuresChange in adult food security status, mean usual intakes of nutrients and food groups, and Healthy Eating Index-2010 scores were the main outcome measures.Statistical analyses performedLinear mixed models estimated changes in outcomes by intervention group and by adult food security status over time.ResultsImprovements in adult food security score (–0.7 ± 0.3; P = .01), Healthy Eating Index-2010 total score (4.2 ± 1.1; P < .0001), and empty calories component score (3.4 ± 0.5; P <.0001) from baseline to follow-up were observed in treatment and comparison groups, but no statistically significant changes were found for adult food security status, dietary quality, and usual intakes of nutrients and food groups between the 2 groups over time. The intervention effect on dietary quality and usual intake changes over time by adult food security status were also not observed.ConclusionsFood pantry clients in treatment and comparison groups had higher food security and dietary quality at the follow-up evaluation of the Voices for Food intervention trial compared with baseline, despite the lack of difference among the groups as a result of the experimental coaching component.  相似文献   
6.
Kinase alterations are increasingly recognised as oncogenic drivers in mesenchymal tumours. Infantile fibrosarcoma and the related renal tumour, congenital mesoblastic nephroma, were among the first solid tumours shown to harbour recurrent tyrosine kinase fusions, with the canonical ETV6::NTRK3 fusion identified more than 20 years ago. Although targeted testing has long been used in diagnosis, the advent of more robust sequencing techniques has driven the discovery of kinase alterations in an array of mesenchymal tumours. As our ability to identify these genetic alterations has improved, as has our recognition and understanding of the tumours that harbour these alterations. Specifically, this study will focus upon mesenchymal tumours harbouring NTRK or other kinase alterations, including tumours with an infantile fibrosarcoma-like appearance, spindle cell tumours resembling lipofibromatosis or peripheral nerve sheath tumours and those occurring in adults with a fibrosarcoma-like appearance. As publications describing the histology of these tumours increase so, too, do the variety kinase alterations reported, now including NTRK1/2/3, RET, MET, RAF1, BRAF, ALK, EGFR and ABL1 fusions or alterations. To date, these tumours appear locally aggressive and rarely metastatic, without a clear link between traditional features used in histological grading (e.g. mitotic activity, necrosis) and outcome. However, most of these tumours are amenable to new targeted therapies, making their recognition of both diagnostic and therapeutic import. The goal of this study is to review the clinicopathological features of tumours with NTRK and other tyrosine kinase alterations, discuss the most common differential diagnoses and provide recommendations for molecular confirmation with associated treatment implications.  相似文献   
7.
8.
The purpose of this study was to investigate the association between habitual snoring (HS), middle ear disease (MED), and speech problems in children with cleft palate. This cross-sectional study included children aged 2.0–7.9 years with non-syndromic cleft palate anomalies. Parents completed the Pediatric Sleep Questionnaire and a questionnaire about MED. Audiograms and speech assessment were also conducted. Ninety-five children were enrolled; 15.2% of families reported HS, 97.6% MED, and 17.1% speech problems. HS (37.5% vs 10.3%, P = 0.007) and early episodes of MED (92.3% vs 58.2%, P = 0.021) were more likely to be reported for children with isolated cleft palate when compared to those with cleft lip and palate. Children with cleft lip and palate had a higher frequency of MED with effusion compared to those with Robin sequence (86.4% vs 57.1%, P = 0.049). The odds ratio for HS in children with ≥1 episode of MED in the last year was 7.37 (95% confidence interval 1.55–35.15, P = 0.012). There was a trend for children with speech problems reported by parents to have HS (30.8% vs 11.5%, P= 0.076). Anatomical factors play a role in the frequency of upper airway symptoms in children with cleft palate. A recent history of at least one episode of MED was associated with an increased frequency of HS.  相似文献   
9.
Oocyte and embryo grading is one of the most important steps in assisted reproductive technology to identify the best among cultured embryos for transfer or vitrification. The most commonly used non-invasive method is morphological assessment of gametes and embryos using a microscope. This method despite being simple and cost-effective has interobserver and intraobserver variability and subjectivity and has little to offer about the physiological state of embryos. This review sourced research articles and reviews pertaining to other non-invasive assessment methodologies from Medline and PubMed to collate latest technologies in vogue and identify novel methodologies of the future. The review assesses the current understanding in oocyte and embryo grading and touches upon novel non-invasive techniques and potential biomarkers to identify the best embryo. The latest available literature on time-lapse imaging, hierarchical algorithms, omics (consisting of proteomics and secretomes), miRNAs, mitochondrial RNAs and artificial intelligence has been accessed to summarize the enormous information available, to identify gaps in current interpretations, to identify emerging technologies and to provide direction for future research. This review will greatly benefit anyone practicing assisted reproduction and clinical embryology.  相似文献   
10.
Measuring outcomes in health care have become mandatory as regulatory agencies, institutional guidelines, employers, and consumer groups advocate for quality health care focusing on improving patient outcomes. System-level quality departments often provide a framework for performance improvement (PI) that supports the organizational PI plan. However, nurses must learn to lead and be actively involved in projects in the radiology department to ensure key performance indicators are developed with on-the-ground quality management to improve patient outcomes, system performance, and professional development. This article explores such efforts at a large women’s specialty hospital in the Southern United States.  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