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   27767篇
  免费   3131篇
  国内免费   1001篇
耳鼻咽喉   180篇
儿科学   286篇
妇产科学   231篇
基础医学   1010篇
口腔科学   579篇
临床医学   4095篇
内科学   2040篇
皮肤病学   182篇
神经病学   860篇
特种医学   645篇
外国民族医学   7篇
外科学   1450篇
综合类   4345篇
现状与发展   2篇
一般理论   2篇
预防医学   6060篇
眼科学   129篇
药学   4892篇
  83篇
中国医学   4178篇
肿瘤学   643篇
  2024年   219篇
  2023年   743篇
  2022年   1226篇
  2021年   1469篇
  2020年   1541篇
  2019年   1201篇
  2018年   1099篇
  2017年   1229篇
  2016年   1313篇
  2015年   1195篇
  2014年   2243篇
  2013年   2412篇
  2012年   1988篇
  2011年   1998篇
  2010年   1531篇
  2009年   1393篇
  2008年   1267篇
  2007年   1221篇
  2006年   1067篇
  2005年   852篇
  2004年   716篇
  2003年   621篇
  2002年   498篇
  2001年   430篇
  2000年   332篇
  1999年   328篇
  1998年   264篇
  1997年   206篇
  1996年   191篇
  1995年   144篇
  1994年   144篇
  1993年   102篇
  1992年   113篇
  1991年   90篇
  1990年   76篇
  1989年   60篇
  1988年   56篇
  1987年   37篇
  1986年   48篇
  1985年   52篇
  1984年   43篇
  1983年   21篇
  1982年   19篇
  1981年   19篇
  1980年   27篇
  1979年   9篇
  1978年   17篇
  1977年   11篇
  1976年   4篇
  1975年   8篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
3.
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   
4.
ABSTRACT

Objective

To investigate primary care physician clinical practice patterns, barriers, and education surrounding pediatric physical activity (PA), and to compare practice patterns by discipline.  相似文献   
5.
Although numerous studies have proven the medicinal values of Yulangsan polysaccharide (YLSP), the toxicity of this active ingredient is unknown. In the acute toxicity study, a single oral administration of 24 g/kg YLSP caused neither toxicological symptoms nor mortality, and the LD50 was estimated >24 g/kg. In the chronic toxicity study, we administered doses of 0, 0.6, 1.2 and 2.4 g/kg YLSP in rats by oral gavage for 26 weeks followed by a 3-week recovery period. There was no mortality or remarkable clinical signs observed during this 26-week study. Additionally, there were no toxic differences in the following parameters: body weight, food consumption, hematology, clinical biochemistry, organ weight, and macroscopic findings. There were no adverse effects on histopathology observed in males or female rats treated with YLSP. Based on the results, the no-observed-adverse-effect-level of YLSP in rats is greater than 2.4 g/kg when administered orally for 26 consecutive weeks.  相似文献   
6.
Determining aortic stenosis (AS) severity is clinically important. Calculating aortic valve (AV) area by means of the continuity equation assumes a circular left ventricular outflow tract (LVOT). The full impact of this assumption in calculating AV area is unknown. Predictors of noncircular LVOT shape in patients with AS are undefined.In 109 adult patients with AS who underwent multiplanar transesophageal echocardiography, we calculated AV area by means of the standard continuity method and by a modified method involving planimetric LVOT area.We found 54 circular, 37 horizontal-oval, 8 vertical-oval, and 10 irregular LVOTs. Area derived by direct planimetry correlated better with the modified than the standard continuity method (r=0.89 vs r=0.85; both P=0.0001). Valve areas of patients with mild, moderate, or severe AS by planimetry were more often mischaracterized with use of the standard than modified method (29 vs 18; P <0.0001). Horizontal-oval AV area derived by planimetry (1.28 ± 0.55 cm2) was underestimated by the standard method (1.05 ± 0.47 cm2; P=0.001), but not by the modified method. Congenital AV morphology and low cardiac index were the only multivariate predictors of horizontal-oval shape. Low cardiac index was the only predictor of noncircular shape.More than half our patients with AS had noncircular LVOTs. Using the modified method reduces mischaracterizations of AS severity. Congenital AV morphology and low cardiac index predict horizontal-oval or noncircular shape. These data suggest the value of direct LVOT measurement to calculate AS severity in patients who have congenital AV or a low cardiac index.  相似文献   
7.
Objective: A multidisciplinary vocational rehabilitation programme, the Vocational Enablement Protocol (VEP) was developed to address the specific needs of employees with hearing difficulties. In the current study we evaluated the process of implementing the VEP in audiologic care among employees with hearing impairment. Design: In conjunction with a randomized controlled trial, we collected and analysed data on seven process parameters: recruitment, reach, fidelity, dose delivered, dose received and implemented, satisfaction, and perceived benefit. Study sample: Sixty-six employees with hearing impairment participated in the VEP. The multidisciplinary team providing the VEP comprised six professionals. Results: The professionals performed the VEP according to the protocol. Of the recommendations delivered by the professionals, 31% were perceived as implemented by the employees. Compliance rate was highest for hearing-aid uptake (51%). Both employees and professionals were highly satisfied with the VEP. Participants rated good perceived benefit from it. Conclusions: Our results indicate that the VEP could be a useful treatment for employees with hearing difficulties from a process evaluation perspective. Implementation research in the audiological setting should be encouraged in order to further provide insight into parameters facilitating or hindering successful implementation of an intervention and to improve its quality and efficacy.  相似文献   
8.
目的:探究超脉冲CO2点阵激光联合富血小板血浆(PRP)治疗面部痤疮凹陷性瘢痕的疗效。方法:72例面部痤疮凹陷性瘢痕患者,随机分为观察组(36例)和对照组(36例)。对照组采用超脉冲CO2点阵激光治疗,观察组采用超脉冲CO2点阵激光联合PRP治疗。比较两组患者的灰度差异、时间指标、瘢痕程度、疼痛、不良反应及视觉评估。结果:观察组的并发症发生率为11.11%,低于对照组的36.11%,差异具有统计学意义(P<0.05)。治疗后,两组患者的灰度差异率均减小,且观察组患者的灰度差异率显著低于对照组,差异具有统计学意义(P<0.05)。治疗后,观察组的炎性渗出时间、红肿时间、愈合时间、停工时间及瘢痕程度评分均低于对照组,差异均具有统计学意义(P<0.05);但疼痛度评分组间比较,差异无统计学意义(P>0.05)。结论:超脉冲CO2点阵激光联合PRP治疗面部痤疮凹陷性瘢痕效果较好,可有效降低瘢痕程度,减少治疗时间及并发症的发生,帮助患者迅速回归正常工作与生活,值得临床推广使用。  相似文献   
9.
目的探讨评教评学模式在肿瘤外科护理带教中的应用效果。方法选择2017年6月—2019年2月于该院肿瘤外科实习的88名护生作为该次研究对象,随机将护生分为对照组与观察组,两组分别有护生44名,对照组给予传统带教方法,观察组给予评教评学模式带教,比较两组护生的护理带教结果。结果观察组护生对带教老师综合能力评价优良率是92.0%,对照组评价优良率是76.0%,组间对比差异有统计学意义(χ^2=4.192,P=0.041<0.05)。观察组带教老师对护生综合能力评价优良率是90.9%,对照组评价优良率是72.7%,组间对比差异有统计学意义(χ^2=4.889,P=0.027<0.05)。观察组护生的理论知识与实操技能考核成绩均要显著比对照组高,差异有统计学意义(P<0.05)。结论评教评学模式在肿瘤外科护理带教中具有显著应用价值,可充分激发师生的教学积极性,改善护理教学质量。  相似文献   
10.
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