全文获取类型
收费全文 | 109093篇 |
免费 | 11091篇 |
国内免费 | 3254篇 |
专业分类
耳鼻咽喉 | 859篇 |
儿科学 | 1314篇 |
妇产科学 | 1054篇 |
基础医学 | 12685篇 |
口腔科学 | 3853篇 |
临床医学 | 11106篇 |
内科学 | 11246篇 |
皮肤病学 | 1541篇 |
神经病学 | 6988篇 |
特种医学 | 3405篇 |
外国民族医学 | 13篇 |
外科学 | 7587篇 |
综合类 | 15848篇 |
现状与发展 | 8篇 |
一般理论 | 3篇 |
预防医学 | 19065篇 |
眼科学 | 1364篇 |
药学 | 14519篇 |
117篇 | |
中国医学 | 5920篇 |
肿瘤学 | 4943篇 |
出版年
2024年 | 376篇 |
2023年 | 1943篇 |
2022年 | 3877篇 |
2021年 | 5330篇 |
2020年 | 5048篇 |
2019年 | 4403篇 |
2018年 | 4026篇 |
2017年 | 4318篇 |
2016年 | 4403篇 |
2015年 | 4298篇 |
2014年 | 7459篇 |
2013年 | 8131篇 |
2012年 | 7206篇 |
2011年 | 7546篇 |
2010年 | 5672篇 |
2009年 | 5283篇 |
2008年 | 5080篇 |
2007年 | 5078篇 |
2006年 | 4347篇 |
2005年 | 3807篇 |
2004年 | 3220篇 |
2003年 | 2890篇 |
2002年 | 2270篇 |
2001年 | 2157篇 |
2000年 | 1689篇 |
1999年 | 1517篇 |
1998年 | 1404篇 |
1997年 | 1276篇 |
1996年 | 1104篇 |
1995年 | 988篇 |
1994年 | 951篇 |
1993年 | 758篇 |
1992年 | 729篇 |
1991年 | 617篇 |
1990年 | 532篇 |
1989年 | 545篇 |
1988年 | 476篇 |
1987年 | 404篇 |
1986年 | 321篇 |
1985年 | 409篇 |
1984年 | 314篇 |
1983年 | 196篇 |
1982年 | 219篇 |
1981年 | 163篇 |
1980年 | 170篇 |
1979年 | 125篇 |
1978年 | 84篇 |
1977年 | 61篇 |
1976年 | 77篇 |
1974年 | 46篇 |
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
41.
目的:分析2010年至2018年甲状腺结节相关SCI论文,并建模进行定性与定量分析。方法:利用文献计量学中的引文分析、共被引分析、数据可视化、聚类分析等方法,使用CiteSpace分析工具,分析来源于Web of ScienceTM核心合集数据库中有关论文的出版情况、国家、机构、作者、知识基础与研究热点。结果:到2018年10月31日截止,研究了4 618篇论文。发表论文数:美国在国家/地区中排名第一,延世大学在研究机构中排名第一,Kwak JY在所有作者中排名第一。从2010年开始,每年发表的论文数量都在稳步增长,有相当多的论文发表在如《新英格兰杂志》、《THYROID》、《JAMA》、《CELL》等高影响因子的期刊上。甲状腺结节的SCI论文参考文献聚类为6类,分别是papillary-like nuclear feature、current statu、radiofrequency ablation、ultrasound elastography、goiter area、data system。代表研究前沿的关键词是meta-analysis、recommendation、thyroid carcinoma、shear wave elastography与bethesda system。结论:本文通过对国际上甲状腺结节的研究基础、研究热点的分析,阐述了甲状腺结节的研究趋势,为我国医学工作者的研究提供参考。 相似文献
42.
背景 在人口老龄化日益加剧的社会背景之下,家庭养老功能不断减弱,机构养老成为今后发展的必然趋势。据报道,很多养老机构的老年人营养不合理,严重影响老年人的健康状况与生活质量。目的 通过调查北京市养老机构老年人营养现状及其影响因素,为全科医师营养教育及老年人生活质量提升提供理论依据。方法 2014年10月-2015年12月,采用方便整群抽样的方法,抽取了北京市7家养老机构,对符合纳入标准的老年人进行面对面问卷调查,问卷内容包括:一般情况、微型营养评定量表(MNA)、日常生活活动能力指数(BI)、老年人抑郁量表(GDS)。采用二元Logistic回归分析养老机构老年人营养状况的影响因素。结果 本研究共发放问卷258份,回收有效问卷258份,有效回收率为100%。被调查的258例老年人中,存在营养不良及存在营养不良发生风险的老年人共计75例(29.1%)。不同年龄、性别、婚姻状况、体质指数(BMI)、医疗费用支付方式、生活自理能力及精神状态的老年人营养状况比较,差异有统计学意义(P<0.05)。二元Logistic回归分析结果显示:年龄〔OR(95%CI)=2.349(1.070,5.156)〕、BMI〔OR(95%CI)=0.092(0.036,0.239)〕、医疗费用支付方式〔OR(95%CI)=0.208(0.083,0.522)〕、日常活动能力〔OR(95%CI)=10.214(3.099,33.669)〕、患病种数〔OR(95%CI)=2.682(1.248,5.763)〕及精神状态〔OR(95%CI)=4.822(2.005,11.600)〕是老年人营养状况的影响因素(P<0.05)。结论 北京地区养老机构的老年人面临着营养不良及营养不良发生风险的健康威胁,高龄、低BMI、抑郁、合并多种疾病、日常活动能力低下及无医保是其独立危险因素,需要对老年人加强个性化营养教育和营养治疗。 相似文献
43.
目的探讨护理教学查房在ICU教学中的临床应用效果。方法选定2018年1月-2019年1月来本院实习的100例学生,按照教学查房方法分为对照组(50例)与观察组(50例),前者采用传统教学查房方法,后者采用针对性教学查房方法。通过出科操作考试及理论考试后,比较2组实习学生的操作考核成绩、理论考核成绩指标。结果教学结束,观察组实习学生的操作考核成绩(94.11±3.54)分、理论考核成绩(85.74±5.39)分均高于对照组实习学生(P<0.05)。结论针对性教学查房方法可有效提高实习学生的操作考核成绩、理论考核成绩,改善其教学质量。 相似文献
44.
To evaluate the anthropometric indexes in subjects with varicocele compared to controls and the incidence of varicocele in different body mass index (BMI) groups for the purpose of exploring the association between varicocele and anthropometric indexes. A comprehensive literature search was conducted by using PubMed, MEDLINE, EMBASE databases and Cochrane Library up to February 2019. A systematic review and meta‐analysis was conducted by STATA, and Newcastle–Ottawa Scale was utilised for assessing risk of bias. Ultimately, 13 articles containing seven case–control studies and six cross‐sectional studies with 1,385,630 subjects were involved in our study. Pooled results demonstrated that varicocele patients had a lower BMI (WMD = ?0.77, 95% CI = ?1.03 to ?0.51) and a higher height than nonvaricocele participants, especially in grade 3 varicocele patients. Subgroup analyses showed that normal BMI individuals had a higher risk of varicocele than obese or overweight individuals and a lower risk than underweight individuals. In conclusion, this study indicates that varicocele patients have a lower BMI and a higher height than nonvaricocele participants. Moreover, men with excess bodyweight have a lower incidence of varicocele compared to normal weight or underweight people. That is to say, high BMI and adiposity protect against varicocele and high BMI is associated with a decreased risk of varicocele. 相似文献
45.
Factors predicting the development of pressure ulcers in an at‐risk population who receive standardized preventive care: secondary analyses of a multicentre randomised controlled trial
下载免费PDF全文
![点击此处可从《Journal of advanced nursing》网站下载免费的PDF全文](/ch/ext_images/free.gif)
46.
Precise data on food chemical composition is crucial for any quantitative nutrition research and indispensable for evaluation and planning of computer-based menus. Moreover, exact food chemical composition is of the utmost importance in composing specific diets that may be low in certain essential nutrients. Therefore, this research evaluated a weekly vegan menu using three different food composition databases (FCDB): the Croatian, the official Danish Food Composition Database and the United States Department of Agriculture (USDA) – National Nutrient Database for Standard Reference. Significant differences (p < 0.05) were determined in evaluated and optimised offers for the same menu when using different FCDBs. Furthermore, in these menus quantities of some nutrients have not reached official daily recommendations needed for prevention of non-communicable diseases. In this research, new vegan menus that can provide adequate quantity of essential nutrients, regardless of FCDB utilized, were created with linear optimisation (LO). This resulted in high quality daily menu offers. However, depending on the FCDB that was used, optimal menus differed in daily meal combinations, and the effectiveness of the optimisation in the minimisation of differences caused by differences of data in FCDBs was tested. Linear optimisation has been proved to be an effective tool in planning of specific diets, such as vegan diets. Nonetheless, the quality of computer-planned menus depends heavily on the quality of FCDB used. 相似文献
47.
48.
49.
《Vaccine》2022,40(28):3851-3860
We propose a probabilistic model to quantify the cost-benefit of mass Vaccination Scenarios (VSs) against COVID-19. Through this approach, we conduct a six-month simulation, from August 31st, 2021 to March 3rd, 2022, of nine VSs, i.e., the three primary vaccine brands in Brazil (CoronaVac, AstraZeneca and Pfizer), each with three different vaccination rates (2nd doses per week). Since each vaccine has different individual-level effectiveness, we measure the population-level benefit as the probability of reaching herd immunity (HI). We quantify and categorize the cost-benefit of VSs through risk graphs that show: (i) monetary cost vs. probability of reaching HI; and (ii) number of new deaths vs. probability of reaching HI. Results show that AstraZeneca has the best cost-benefit when prioritizing acquisition costs, while Pfizer is the most cost-beneficial when prioritizing the number of deaths. This work provides helpful information that can aid public health authorities in Brazil to better plan VSs. Furthermore, our approach is not restricted to Brazil, the COVID-19 pandemic, or the mentioned vaccine brands. Indeed, the method is flexible so that this study can be a valuable reference for future cost-benefit analyses in other countries and pandemics, especially in the early stages of vaccination, when data is scarce and uncertainty is high. 相似文献
50.
Altayeb Abdalla Ahmed 《Medicine》2021,100(19)
Estimating stature based on body/limb parts can help define the characteristics of unidentified bodies. The most studied upper limb part is the hand, although few studies have examined whether stature can be estimated using fingers plus other hand dimensions. Moreover, there is paucity in anthropometric studies that determined whether bilateral whole limb parts (e.g., arms, forearms, and hands) are related to stature among the living subjects.This prospective cross-sectional study aimed to evaluate the relationship between different upper limb measurements and the stature of Saudi men. Furthermore, I assessed whether upper limb asymmetry was present, and developed regression models to estimate stature based on different available measurements. Stature and 13 upper limb parameters were measured for 100 right-handed Saudi men who were 18 to 24 years old.All measurements were positively correlated with stature (P < .001), and the best single predictor was the bilateral ulnar length. Asymmetry was more pronounced in the hand measurements. A multiparameter model provided reasonable predictive accuracy (±3.77–5.68 cm) and was more accurate than single-parameter models. Inclusion of the right-side fingers improved the model''s accuracy.This study developed potential models for estimating stature during the identification of bodies of Saudi men. 相似文献