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   938篇
  免费   69篇
  国内免费   18篇
耳鼻咽喉   10篇
儿科学   3篇
妇产科学   3篇
基础医学   58篇
口腔科学   124篇
临床医学   172篇
内科学   49篇
皮肤病学   9篇
神经病学   21篇
特种医学   19篇
外科学   48篇
综合类   241篇
预防医学   119篇
眼科学   12篇
药学   83篇
  4篇
中国医学   36篇
肿瘤学   14篇
  2024年   2篇
  2023年   19篇
  2022年   40篇
  2021年   62篇
  2020年   79篇
  2019年   37篇
  2018年   50篇
  2017年   36篇
  2016年   28篇
  2015年   31篇
  2014年   92篇
  2013年   81篇
  2012年   84篇
  2011年   67篇
  2010年   42篇
  2009年   55篇
  2008年   34篇
  2007年   37篇
  2006年   27篇
  2005年   16篇
  2004年   20篇
  2003年   10篇
  2002年   9篇
  2001年   7篇
  2000年   2篇
  1999年   5篇
  1998年   3篇
  1997年   6篇
  1996年   1篇
  1994年   2篇
  1993年   3篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1989年   3篇
  1987年   2篇
  1985年   2篇
  1984年   2篇
  1983年   3篇
  1982年   5篇
  1981年   8篇
  1980年   2篇
  1979年   3篇
  1976年   3篇
  1973年   1篇
  1969年   1篇
排序方式: 共有1025条查询结果,搜索用时 19 毫秒
1.
目的运用360度评价对我院住培学员的岗位胜任力进行评价,对学员岗位胜任力的现状进行探讨分析。方法使用问卷调查表分别从专业基地教学主任、学员指导教师、同专业学员及学员本人的角度,对2017级222名住培学员的岗位胜任力进行360度评价,利用SPSS22.0对数据进行统计分析。结果连续两年的测评,住院学员8类岗位胜任力的自评和他评得分低于满分,学员在临床基本能力、医患沟通能力、掌握与运用医学知识、团队合作能力4项内容的评分,差异有统计学意义(P<0.05);同时学员在临床基本能力、医生职业精神与素质、医患沟通能力、掌握与运用医学知识、团队合作能力5项内容的评分较上一年相比,差异也有统计学意义(P<0.05)。结论调查结果提示360度评价可帮助住培学员提高岗位胜任力,后续培训应围绕调查结果和以岗位胜任力为导向来调整与设置,需增加人文属性内容的培训以及再量化培训测评内容、指标和进一步完善考评反馈机制。  相似文献   
2.
Previous research in Scotland used a merging approach to combine census boundary data for geographies specific to 1981, 1991 and 2001 to create Consistent Areas Through Time (CATTs) for the analysis of health and social data for small areas. In this paper, we adopt the same methodology to integrate the 2011 Scottish Output Areas to the CATTs. First, we overlaid the 2001 Output Areas upon the 2011 Output Areas to create SUPER OAs, which were then combined with SUPER EDs, which represented a consistent small area geography for 1981 and 1991. This resulted in 8,548 CATTs providing a consistent geography for the 1981, 1991, 2001 and 2011 Censuses in Scotland. We demonstrate the utility of the CATTs by exploring the correlations between deprivation, the proportion of the population who were permanently sick and those with degree qualifications, across the 4 censuses, a research angle impossible without consistent geographies. We have provided a resource that enables users to deepen their understanding of small area social changes in Scotland between the 1981 and 2011 Censuses.  相似文献   
3.
A pregelatinized starch (PGS) was derivatized with sodium chloroacetate (SCA) in alcoholic medium under alkaline condition to produce carboxymethyl pregelatinized starch (CMPGS) with various degrees of substitution (DS). Influence of the molar ratio of SCA to the glucopyranose units (SCA/GU), reaction time, temperature and the amount of sodium hydroxide on the degree of substitution (DS) and the reaction efficiency (RE) was studied. An optimal concentration of 30% of NaOH, for a reaction time of 1 h at 50 °C and molar ratio (SCA/GU) equal to 1.0, yielded an optimal DS of 0.55 and a RE of 55%. SEM micrographs revealed that the carboxymethylation assigned the structural arrangement of CMPGS and caused the granular disintegration. Wide angle diffraction X-ray (XRD) showed that the crystallinity of starch was obviously varied after carboxymethylation. New bands in FTIR spectra at 1417 and 1603 cm−1 indicated the presence of carboxymethyl groups. The solubility and viscosity of CMPGS increased with an increase in the degree of modification. In order to investigate the influence of DS on physical and drug release properties, CMPGS obtained with DS in the range of 0.12–0.55 was evaluated as tablet excipient for sustained drug release. Dissolution tests performed in phosphate buffer (pH 6.8), with Ibuprofen as drug model (25% loading) showed that CMPGS seems suitable to be used as sustained release excipient since the drug release was driven over a period up to 8 h. The in vitro release kinetics studies revealed that all formulations fit well with Korsmeyer-Peppas model and the mechanism of drug release is non-Fickian diffusion.  相似文献   
4.
Risedronate is a nitrogen-containing bisphosphonate for the treatment and prevention of postmenopausal osteoporosis. The current work aims to develop a novel green HPLC-UV method for the rapid analysis of risedronate sodium in bulk and tablet formulation. The analyzed samples were separated on Waters Atlantis dC18 (150 mm × 3.9 mm; 5 μm) column using a green mobile phase consisting of potassium phosphate buffer pH 2.9 and potassium edetate buffer pH 9.5 in a ratio of 1:2, the final pH was adjusted to 6.8 with phosphoric acid, the mobile phase was pumped at a rate of 1.0 mL/min, with column temperature set at 30 °C, eluted samples were detected at 263 nm and the chromatographic run time was 3.0 min. The method was found to be linear over the concentration range of 14–140 μg/mL with a correlation coefficient (r2) of 0.9994. Accuracy and precision were evaluated from three QC samples (LQC, MQC and HQC) together with the five calibrators where the percentage accuracy was found to be 101.84%. Processed quality control samples of risedronate sodium were tested for stability at different conditions, short term, long term and freeze- thaw stability. The current method was further extended to study the content uniformity of Actonel® tablets following United States Pharmacopoeia (USP) guidelines. The proposed method was fully validated as per ICH guidelines.  相似文献   
5.
BackgroundFrequent patient handling activities present numerous challenges to healthcare workers. A variety of products are available to assist with in-bed positioning but few comparative studies have been completed to ascertain turning effectiveness.MethodsThe purpose of this study was to compare two turning devices (air-powered positioning system with wedges versus ceiling lift with pillows) for in-bed repositioning and turning effectiveness. The study took place at a large community hospital in the Midwestern USA and used a prospective, four-group crossover study design to compare devices.ResultsThe two turning groups were not significantly different for any of the demographic variables. The use of an air-powered positioning system with wedges achieved a greater degree of turn and maintained that turn after an hour better than the lift device with pillows. There were no hospital acquired pressure injuries in either group.ConclusionThe devices used demonstrated significant differences in turn angle achieved and ability to maintain the turn at one hour. Future studies need to further delineate the ideal method for turning and compare devices to identify best practice and equipment. An effective turning method would integrate ease of use with the ability to achieve an optimal degree of turn in order to prevent hospital acquired pressure injuries while also decreasing caregiver injuries.  相似文献   
6.
7.
目的:探究针灸联合推拿治疗对腰椎间盘突出症患者疼痛及功能恢复的影响。方法:选取2017年8月-2018年6月于我院治疗的90例腰椎间盘突出症患者,采用随机数字表法分为两组,各45例。对照组给予常规治疗,观察组采用针灸联合推拿治疗。对比两组临床疗效、治疗前后中医证候积分、疼痛评分(Visual Analogue Scale,VAS)及功能恢复评分(Japanese Orthopaedic Association Scores,JOA)。结果:相较于对照组观察组的治疗总有效率较高,差异有统计学意义(P<0.05);观察组治疗后各中医证候积分分别为(1.05±0.64)分、(1.12±0.87)分、(1.01±0.62)分、(0.94±0.12)分,VAS评分为(1.84±0.22)分均低于对照组(2.57±0.81)分、(2.63±0.91)分、(2.94±0.68)分、(1.38±0.36)分、(3.24±0.36)分,JOA评分为(21.33±2.46)分高于对照组(18.57±2.24)分,差异有统计学意义(P<0.05)。结论:针灸联合推拿在治疗腰椎间盘突出症中获得较好的临床效果,患处疼痛感有效缓解,腰椎功能明显改善,值得推广应用。  相似文献   
8.
IntroductionPractical training for medical students is provided during the final years of study and is determined by several conditioning factors, including the MIR training that students receive simultaneously. In general, practical training evaluation receives much less attention than the theoretical one; its quality is not evaluated, and the professors do not receive feedback. The objective of our study was to determine how students value practical training in pulmonology rated the experience after completing a three-week rotation, in order to apply the information gained toward a process of continual improvement.MethodsThe study included 2 anonymous surveys taken by medical students during the same academic year-one internal, prepared by the Department of Pneumology, itself, and another external one, prepared by the Evaluation Unit for Teaching Excellence at the University of Salamanca.ResultsOn the internal evaluation, student opinions of their practical training ran high (8.26) and the perceived usefulness was also high (8.23), on a scale of 0 to 10 and no differences were noted according to whether the survey was taken during their fourth, fifth, or sixth year of study. These results agree with those obtained in the external evaluation with a mean value of 4.56 on a scale of 0 to 5. Student preferences during their rotation in the department were for hospitalization and consultation units, with the technical areas being lesser valued.ConclusionsAchieving and maintaining a high quality of practical training is a goal that should be consistently evaluated so that professors may receive feedback (internal and external). Rotations in the Department of Pneumology provide an opportunity to improve the perception that medical students have regarding this specialty. It is imperative to reflect upon the contents of these rotations, seeking a balance between clinical areas and technical areas.  相似文献   
9.
OBJECTIVES: This study evaluated the effect of a warm or cold air-dry stream for solvent evaporation on the microtensile resin-dentin bond strength (muTBS), nanoleakage pattern (SEM), degree of conversion (DC) and solvent evaporation rates (SE) of an ethanol/water- (Adper Single Bond, [SB] 3MESPE) and an acetone-based (Prime & Bond 2.1, [PB] Dentsply), two-step etch-and-rinse adhesive system. MATERIALS AND METHODS: Adhesives were applied on demineralized dentin surfaces. For SE, a warm or cold air-dry stream (10 s) was applied prior to light-activation (10 s). Bonded sticks (0.8mm2) were tested in tension (0.5 mm/min). Two bonded sticks from each tooth were immersed in a 50% (w/v) solution of silver nitrate (24 h), photodeveloped (8 h) and analyzed by SEM. The DC and solvent evaporation rate of the adhesives were evaluated under FTIR and analytical balance, respectively. Data were analyzed by two-way ANOVA and Tukey test (alpha=0.05). RESULTS: Higher muTBS and lower nanoleakage were observed when the SE step was performed with warm air-dry stream. However, the DC of the adhesives was not altered by the use of a warm air-dry. CONCLUSIONS: The use of a warm air-dry stream seems to be a clinical tool to improve the bond strength and the quality of the hybrid layer (less nanoleakage infiltration), since it might reduce the number of pores within the adhesive layer.  相似文献   
10.

Objectives

The aim of this work was to investigate the effect of high irradiance curing on resultant degree of conversion of ‘flowable’ resin composites and their counterpart higher viscosity paste materials.

Methods

Five commercial flowable materials (Venus; Heraeus Kulzer, Synergy D6; Coltene, Premise; Kerr, Grandio; Voco and Gradia; GC Corp) and their counterpart higher viscosity restorative versions were tested. Specimens were cured with a halogen Swiss Master Light (EMS, Switzerland) using five different curing protocols with similar radiant exposure (18 J/cm2): 400 mW/cm2 for 45 s, 900 mW/cm2 for 20 s, 1500 mW/cm2 for 12 s, 2000 mW/cm2 for 9 s and 3000 mW/cm2 for 6 s. Degree of conversion (DC) was measured in real time by Fourier transform near infrared spectroscopy (FT-NIRS).

Results

Three- and subsequent two way ANOVA testing revealed significant differences (p ≤ 0.02) with respect to “composite type” and “cure protocol” for DC for all 5 product comparisons. Supplementary one-way ANOVA also revealed significant differences between curing protocols (p < 0.05). The majority of higher viscosity resin composite paste materials exhibited similar DC regardless of curing protocol. However, a significant decrease in DC for specimens cured at 3000 mW/cm2 for 6 s compared with 400 mW/cm2 for 45 s was observed for the flowable materials, Grandio (41 ± 0.36 and 62 ± 1.15%, respectively) and Venus (44 ± 0.44 and 67 ± 0.44%, respectively). Conversely, other flowable materials exhibited little or no significant differences between curing modes. Generally, a higher degree of conversion was observed for flowables compared with their more viscous counterpart, except at high irradiance for those materials where a reciprocal relationship with exposure time was not observed.

Conclusions

The validity of exposure reciprocity law and final degree of conversion depends on several factors, amongst which resin viscosity and filler content were important. Practitioners should be aware of the importance of resin composite constituents and irradiation protocols. Information on material composition and appropriate radiation sources by manufacturers may assist practitioners with the selection of appropriate curing protocols for specific material/light curing unit combinations with the aim of reducing the incidence of under-cured restorations and the clinical impact thereof.  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