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   29029篇
  免费   2673篇
  国内免费   768篇
耳鼻咽喉   416篇
儿科学   501篇
妇产科学   313篇
基础医学   2552篇
口腔科学   511篇
临床医学   6524篇
内科学   2717篇
皮肤病学   102篇
神经病学   3010篇
特种医学   1832篇
外科学   2989篇
综合类   4344篇
现状与发展   1篇
一般理论   3篇
预防医学   2854篇
眼科学   280篇
药学   1497篇
  260篇
中国医学   1335篇
肿瘤学   429篇
  2024年   102篇
  2023年   644篇
  2022年   1229篇
  2021年   1719篇
  2020年   1730篇
  2019年   1297篇
  2018年   1249篇
  2017年   1298篇
  2016年   1144篇
  2015年   1110篇
  2014年   2457篇
  2013年   2814篇
  2012年   1914篇
  2011年   1964篇
  2010年   1502篇
  2009年   1416篇
  2008年   1357篇
  2007年   1195篇
  2006年   1038篇
  2005年   845篇
  2004年   670篇
  2003年   543篇
  2002年   436篇
  2001年   356篇
  2000年   321篇
  1999年   266篇
  1998年   219篇
  1997年   195篇
  1996年   177篇
  1995年   142篇
  1994年   108篇
  1993年   112篇
  1992年   131篇
  1991年   81篇
  1990年   77篇
  1989年   62篇
  1988年   66篇
  1987年   53篇
  1986年   40篇
  1985年   42篇
  1984年   56篇
  1983年   39篇
  1982年   39篇
  1981年   34篇
  1980年   29篇
  1979年   21篇
  1978年   25篇
  1977年   24篇
  1976年   17篇
  1975年   18篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
71.
This study investigates functional disability among some of the nation's most vulnerable older adults: rural Medicaid recipients. Data were provided by 221 older adults (mean age = 75.9 years; 82% women) who were receiving community-based long-term care services through Medicaid. Participants self-reported functional ability involving the completion of six basic activities of daily living (BADLs), three cognitive instrumental activities of daily living (IADLS), and four physical IADLs. Self-reports of depressed affect and the number of physical health conditions were also obtained. Path analysis was used to examine all of the associations among age, gender, number of chronic health conditions, depressed affect and functional disability. The tested model was significant [chi2 (DF = 3, n = 221) = 5.052, p = 0.168; TLI = 0.945; CFI = 0.992; RMSEA = 0.056] and explained 45.1% of the variance in BADL disability. Depressed affect significantly predicted disability in cognitive IADLs and physical IADLs, which predicted disability in BADLs. Age and gender had indirect effects on BADL, through their association with cognitive IADLs and physical IADLs. The number of chronic health conditions exerted both indirect and direct effects on BADL disability. Results are discussed within the context of the growing literature that suggests the importance of psychological variables as predictors of functional disability. Moreover, we discuss whether community-based long-term care is appropriate for older adults with high levels of functional disability.  相似文献   
72.
邵华军  赵力 《河北医学》2002,8(7):583-587
目的 :研究COPD肺心病急性加重期多个器官的受损情况。方法 :采用日本OLYMPUS公司AU10 0 0全自动生化分析仪测量 10 9例肺心病急性加重期患者的 17项血生化指标。并与 110例健康体检者进行对照研究。结果 :两组之间血肌酐 (Cr)差异不显著 (P >0 .0 5 ) ,总胆红素 (TBIL)及空腹血糖 (GLU)差异显著 (P <0 .0 5 ) ,其余 14项生化指标P值均 <0 .0 1,两组间差异非常显著。结论 :COPD肺心病急性加重期除了心力衰竭 ,呼吸衰竭之外 ,还常常伴有肝损害、肾损害、高血糖、低脂低胆固醇血症、低蛋白血症及营养不良。保肝护肾 ,注意血糖血脂及营养支持治疗不容忽视  相似文献   
73.
The aims of this paper are to evaluate the training in out‐patients and in theatre after the recent changes in SpR training. A postal questionnaire was sent to 191 Specialist Registrars (SpRs) in England and Wales and 57 were returned (30%). There were temporal bone facilities within the hospital for 53 SpRs but only three used them because there were no temporal bones. Surgical training was more satisfactory than out‐patient training. Fewer general clinics and more specialized clinics are required, and consultant supervision is still patchy and needs attention.  相似文献   
74.
运动训练联合基因治疗对肾性高血压大鼠肾功能的影响   总被引:1,自引:0,他引:1  
目的观察运动训练联合β1肾上腺素能受体基因治疗对肾性高血压大鼠血压、肾功能、肾脏前肾素原mRNA、肾脏β1受体mRNA和蛋白的影响,探讨其改善肾功能的机制。方法两肾一夹法制作肾性高血压模型,基因治疗采用经鼠尾静脉注射阳离子脂质体与β1反义寡核苷酸方法。检测大鼠血压、肾功能变化。半定量RT—PCR测定肾脏β1受体mRNA、前肾素原mRNA水平。Western印迹法测检肾脏β1受体的蛋白水平。结果与模型组比较,运动联合基因治疗可使血压下降并维持4周,血压下降最高达41mmHg;尿蛋白量[(45.82±6.56)比(29.12±5.22)mg/L,P〈0.01】、BUN[(13.10±2.62)比(9.05±1.84)mmol/L,P〈0.05]显著降低(P〈0.01,P〈0.05);内生肌酐清除率显著升高(P〈0.01);前肾素原mRNA、β1受体mRNA、蛋白表达水平显著降低(P〈0.05)。结论运动训练联合β1受体反义基因治疗可以明显地降低血压,改善肾功能;且运动训练可以增强基因治疗对β1受体mRNA和蛋白的抑制作用,在转录和翻译水平抑制过度激活的β1受体的表达。  相似文献   
75.
BACKGROUND: We recently implemented the use of an ex-vivo porcine model to teach residents the fundamentals of performing a laparoscopic Nissen fundoplication. METHODS: Residents were trained using intact porcine esophagus, stomach, and spleen placed in a standard video-trainer. They were later asked to complete a survey containing a course evaluation. RESULTS: Sixteen residents (R1-R4) completed the survey. They agreed that (1) the exercise was a valuable use of their limited time, (2) repeating the exercise will be of additional benefit, (3) it will improve their ability to perform or assist in an actual case in the OR, and (4) the surgical principles learned using the model will transfer to other laparoscopic cases. Significant subjective improvements were reported in resident comfort level in assisting in or performing a laparoscopic Nissen fundoplication. CONCLUSIONS: The use of an inexpensive ex-vivo porcine training model increases resident comfort level in performing a Nissen fundoplication in the operating room.  相似文献   
76.
This paper describes a response directed stress management intervention (SMI) in the form of a Jungian based preference awareness education (PAE). It uses the Insights System of personality types to increase awareness of behaviour and communication preferences of self and different others. Eighteen self‐recruited academic employees participated for 7 weeks and received feedback about work preferences and personality type. The aim was to reduce perceptions of stress and interpersonal stress and to increase feelings of job satisfaction and interpersonal satisfaction. The data were analysed using two‐tailed t‐tests. No significant findings were observed for the total sample after training, however, interesting results were found for certain sub‐sample groups. Extravert‐thinking types, reported decreased stress levels (p > 0.018), and participants suffering high stress/interpersonal stress pre‐PAE, reported decreased stress levels (p > 0.010–0.018). Participants suffering low job/interpersonal satisfaction pre‐PAE, reported increased job satisfaction (p > 0.015–0.016). These results suggest that individuals who report high levels of stress and dissatisfaction are most likely to benefit from this type of intervention. Future PAE research might: (a) use pilot studies to meet the intervention preferences of employees that are reluctant to participate in SMIs; (b) include a wait‐list control group; use: (c) a follow up education/measures; (d) and organizational level (stressor directed) SMIs at the same time as response directed initiatives. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   
77.
78.
额叶外伤后早期数字工作记忆的fMRI研究   总被引:5,自引:1,他引:4  
目的:利用功能磁共振成像技术研究额叶外伤后,执行工作记忆任务时脑结构损伤与脑激活功能区的改变。材料和方法:对10例额叶外伤后早期患者(伤后平均31d,其中男性7例,女性3例;平均年龄30.1年)和12例正常志愿者作为对照组(男性7例,女性5例;平均年龄26.9年)分别进行2位和4位数字的正反序工作记忆的实验,使用single-trial设计方法;GE3.0T磁共振机扫描、采集图像,运用AFNI软件包进行数据分析。结果:①正常对照组反序4位数字任务大于正序4位数字脑区有辅助运动区SMA,双侧背外侧前额叶,左侧顶叶,右侧角回;②患者组反序4位数字任务大于正序4位数字的脑区有左侧枕叶;③正常对照组反序4位数字任务大于患者组的部位有左侧DLPFC,左侧角回;正序4位数字大于患者组的部位有左侧枕叶,右侧角回;④患者组反序4位数字任务时大于对照组的部位有楔状回,右侧Broca区;正序4位数字大于对照组的部位有右侧初级运动区MA,右侧额极区。结论:前额叶在脑工作记忆网络中处于重要节点,大脑右侧半球在工作记忆系统中起到巨大代偿作用的脑资源,fMRI提供认知功能损伤的影像学依据,应在临床上发挥更大作用。  相似文献   
79.
Background and objectives: To determine improvement in hand dexterity with targeted laparoscopic skill exercises desirable for use in the operating rooms among in-training laparoscopic gynaecological surgeons and medical students. Design: Cross-sectional study with paired analysis. Setting: Kiel School of Gynaecological Endoscopy and Reproductive Medicine, Germany, between February and April 2005. Subjects: Twenty third-year medical students and 20 in-training gynaecological endoscopic surgeons from various parts of the world. Interventions: Demonstration and explanation of a set of five laparoscopic skill exercises desirable for use in the operating rooms before administering a pretest. This was followed by voluntary practice of these exercises for at least 10 times over 1 day. The posttest was performed the next day once the participant was comfortable performing the skill. Pre- and posttest assessments were conducted by independent supervisors. Main outcome measures: Time to completion of tasks with minimal errors. Results: There was significant reduction in mean time for all the laparoscopic skill exercises performed with dominant, nondominant, and both hands, before and after the training and practice (p-value <0.01; paired t-test). Moderate to high correlation (0.617–0.901) was seen with the intermediate and complex/difficult tasks, whereas low correlation was seen with the simple/easy task (0.200–0.336). Medical students and gynaecologists both showed improvement in performance from pretest to posttest in terms of reduction in mean time taken to perform all the tasks with minimal errors. Conclusions: Simple laparoscopic training devices can substantially help an individual hand’s improvement and acquisition of laparoscopic skills. Simple laparoscopic training devices along with animal models will continue to provide an efficient and effective environment for learning and teaching laparoscopic surgical skills. With this training, performance improves progressively with practice.  相似文献   
80.
Overview Excess spasticity leads to disability that is marked by impaired locomotion, handicapping deformities and, if not controlled, discomfort and pain. Selective peripheral neurotomy in the child is indicated for severe focal spasticity, when botulinum toxin injections cannot delay surgery any longer. Materials and methods Preoperative motor blocks mimicking the outcome of the surgical procedure are essential to establish the objectives of neurotomy. In the lower limb, obturator neurotomy is indicated for spasticity in the adductor muscles, hamstring neurotomy for the knee flexion and tibial neurotomy for the spastic foot. Anterior tibial neurotomy is indicated for the extensor hallucis spasticity and femoral neurotomy for spasticity in the quadriceps. In the upper limb, neurotomy of the pectoralis major and teres major nerves is indicated for spasticity of the internal rotators of the shoulder. Neurotomy of the musculocutaneous nerve is indicated for spasticity of the flexors of the elbow, and neurotomy of median and ulnar nerves are indicated for spasticity of the pronators and flexors of the wrist and fingers. Conclusion Selective peripheral neurotomy is a valuable neurosurgical procedure in well-trained surgical hands for severe focalised spasticity.  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