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   29118篇
  免费   2508篇
  国内免费   316篇
耳鼻咽喉   387篇
儿科学   446篇
妇产科学   522篇
基础医学   1255篇
口腔科学   306篇
临床医学   4948篇
内科学   2764篇
皮肤病学   391篇
神经病学   1283篇
特种医学   684篇
外科学   2516篇
综合类   4165篇
一般理论   1篇
预防医学   5377篇
眼科学   151篇
药学   3635篇
  21篇
中国医学   1377篇
肿瘤学   1713篇
  2024年   62篇
  2023年   587篇
  2022年   1226篇
  2021年   1498篇
  2020年   1538篇
  2019年   1382篇
  2018年   1274篇
  2017年   1162篇
  2016年   1106篇
  2015年   1069篇
  2014年   2752篇
  2013年   2288篇
  2012年   2114篇
  2011年   2186篇
  2010年   1587篇
  2009年   1598篇
  2008年   1513篇
  2007年   1420篇
  2006年   1132篇
  2005年   899篇
  2004年   690篇
  2003年   517篇
  2002年   386篇
  2001年   318篇
  2000年   298篇
  1999年   264篇
  1998年   174篇
  1997年   172篇
  1996年   139篇
  1995年   132篇
  1994年   94篇
  1993年   91篇
  1992年   63篇
  1991年   54篇
  1990年   35篇
  1989年   22篇
  1988年   23篇
  1987年   14篇
  1986年   6篇
  1985年   18篇
  1984年   12篇
  1983年   5篇
  1982年   7篇
  1981年   7篇
  1980年   2篇
  1979年   2篇
  1976年   1篇
  1975年   1篇
  1972年   1篇
  1970年   1篇
排序方式: 共有10000条查询结果,搜索用时 828 毫秒
71.
2种清洗设备洗涤医用器械的质量分析   总被引:2,自引:0,他引:2  
目的通过观察全自动清洗消毒器与超声波清洗机洗涤不同类医用器械的质量,找出不同器械的最佳洗涤方法,为制订各种器械洗涤流程提供依据。方法将回收器械随机分为A洗涤法和B洗涤法。A洗涤法:将回收器械直接放入全自动清洗消毒器内按程序进行清洗、消毒和干燥。B洗涤法:将器械放入超声波机内按程序加酶浸泡、超声波清洗、冷水热水喷淋清洗消毒、上油烘干。比较2种洗涤方法的洗涤效果。结果A洗涤法洗涤后齿类器械剩余残留物为0.52‰,非齿类器械剩余残留物为0.07‰,2种器械洗涤效果差异有统计学意义(!2=28.189,P=0.000),洗涤齿类器械效果差;B洗涤法洗涤齿类器械剩余残留物为0.04‰,非齿类器械剩余残留物为0.01‰,2种器械洗涤效果差异无统计学意义(!2=1.008,P=0.313)。而2组洗涤法洗涤齿类器械效果有统计学意义(!2=44.097,P=0.000);非齿类器械洗涤后剩余残留物对比不明显,洗涤效果差异无统计学意义(!2=2.667,P=0.102)。结论采用超声波清洗机清洗齿类器械洗涤效果佳;而采用全自动清洗消毒器洗涤齿类器械洗涤效果差,但洗涤非齿类器械洗涤容量大,效果好。  相似文献   
72.
病案作为记录医疗活动过程的重要载体,包含着各类丰富的信息。医疗服务质量评价有很多内容是通过病案实现的。作者分析了包括"三级医师查房"在内的20余项在病案中反映的医疗服务质量项目,指出影响质量判断的常见因素,并提出解决的对策与措施。  相似文献   
73.
目的 通过体模检测和病例检查的对照研究,比较计算机X射线摄影(computed radiography,CR)新旧两种不同成像板(IP)对影像质量和病人辐射的影响,探讨新旧IP的使用原则。方法 对新旧IP进行常规暗噪声、均匀性和一致性、擦除完全性检测;根据阈值对比度-细节检测能力(TCDD)技术,75 kV时新旧IP对体模TO.16进行摄影,请3位观察者采用双盲法对所得影像进行观察评分,计算阈值检测指数HT(A);结合临床用相同曝光条件,不同的IP分别对膝关节、胸部、腰椎进行投照,请3位放射专家进行双盲阅片,评价影像质量。结果 新旧IP在物理指标上基本相同,在相同曝光条件下,新IP的检测能力高于旧IP,当旧IP提高20%的辐射剂量后,旧IP检测能力接近新IP。结论 随着IP使用次数的增加,需逐步提高曝光剂量才能保证影像质量;若保持原有剂量不变,IP的检测能力就会下降,将影响疾病的诊断。  相似文献   
74.
PET/CT图像采集时间对图像质量和病灶检出率的影响   总被引:1,自引:0,他引:1  
目的探讨在不影响图像质量和病灶检出率前提下缩短PET/CT图像采集时间的可行性。方法18例接受PET/CT检查的患者,在CT扫描后按1、2、3min/床位依次进行3次PET扫描,共得到54帧图像。患者按体重分为以下3组:(1)45~60kg(7例),(2)61~75kg(7例),(3)76~90k(4例)。由2位有经验的医师共同阅片确定每例患者病变的位置和数目,图像质量由2位医师独立判断。结果3min/床位PET/CT图像上共检出127个病灶,其中最小的病灶直径约为3mm,除1min/床位图像漏检3个病灶外,其他所有病灶均能被1min/床位、2min/床位的图像识别。(1)~(3)组患者在3min/床位采集图像上识别的病灶数分别为71、41、15个,第1组患者的所有病灶在3种不同采集时间图像上均能被识别,第2组患者1min/床位采集图像遗漏了3个病灶,而2min/床位图像识别出的病灶数与3min/床位图像相同。第3组患者的所有病灶在3种采集图像上也均能被识别。1、2min/床位的PET图像质量均较3min/床位图像差,1min/床位图像质量最差,主要表现为图像本底噪声高、对比度差。3组患者中,第3组患者图像质量最差。结论对体重低于60瞻患者,1~3min的采集时间,病变的检出率无明显差异;而对体重60k以上患者,建议选择2~3min/床位的采集时间,对病情较重或不合作患者,根据需要可考虑选择1min/床位的采集时间。  相似文献   
75.
Introduction Vertebral deformities are a common consequence of osteoporosis and are known to decrease quality of life. The Qualeffo–41 is a quality-of-life questionnaire especially developed for measuring quality of life in patients with vertebral deformities. It consists of 41 questions arranged in five domains: pain, physical function, social function, general health perception, and mental function. The objectives of this study were: (1) to develop a shorter version of the Qualeffo–41 by removing redundant questions; and (2) to investigate the scale characteristics, reliability, and validity of this shorter version. Methods The study was performed using data from the Qualeffo validation study and the Multiple Outcomes of Raloxifene Evaluation (MORE) study. The analyses were performed in patients with vertebral deformities (n=579). Factor analysis on polychoric correlations and an item response theory (IRT) model, i.e., the generalized partial credit model (GPCM), were used to create a shorter version of Qualeffo–41. Using GPCM, scoring weights were computed for all items. Results Three items were removed from the data set because of too many missing values. Factor analysis identified three instead of five domains: (1) pain, (2) physical function, and (3) mental function. Five items had factor loadings <0.4 and were not included in the GPCM. After excluding several items, the domains pain (four items), physical function (18 items), and mental function (nine items) showed a good, reasonable, and excellent fit, respectively. This indicates that the mental function domain and the pain domain are more unidimensional than the physical function domain. All three domains showed a very high correlation (r ≥0.95) with the corresponding domains of the Qualeffo–41. Conclusions Qualeffo–31 was developed, consisting of three domains with a reasonable to excellent fit to the GPCM. Although the fit to the GPCM supports the construct validity of the Qualeffo–31, validation in a new study should be performed before using it in practice.  相似文献   
76.
Background. The National Heart, Lung, and Blood Institute (NHLBI) guidelines recommend that patients receive a follow-up outpatient asthma visit after being discharged from an emergency department (ED) for asthma. Objective. To measure the frequency of follow-up outpatient asthma visits and its association with repeat ED asthma visit. Design. We conducted a retrospective cohort study of children with asthma using claims data from a university-based managed care organization from 01 1998 to 10 2000. We performed a multivariate survival analysis using Cox proportional hazards model to determine the effect of follow-up outpatient asthma visits on the likelihood of a repeat ED asthma visit, after controlling for severity of illness, patient age, gender, insurance, and the specialty of the primary care provider. Results: A total of 561 children had 780 ED asthma visits. Of these, 103 (17%) had a repeat ED asthma visit within 1 year. Almost two-thirds of children (66%) did not receive outpatient follow-up for asthma within 30 days of an ED asthma visit. Outpatient asthma visits within 30 days of an ED asthma visit are associated with an increased likelihood (relative risk = 1.80; 95% confidence interval 1.19, 2.72) for repeat ED asthma visits within 1 year. Conclusions. Most patients do not have outpatient follow-up after an ED asthma visit. However, those patients that present for outpatient follow-up have an increased likelihood for repeat ED asthma visits. For the primary care provider, these outpatient follow-up visits signal an increased risk that a patient will return to the ED for asthma and are a key opportunity to prevent future ED asthma visits.  相似文献   
77.
BACKGROUND: SF-12 Health Survey, and European Organisation for Research and Treatment of Cancer Quality of life Questionnaire-C30 are the two main questionnaires proposed and validated for assessing the quality of life in chronic pancreatitis. AIMS: To evaluate the role of the information furnished by both the SF-12 Health Survey and European Organisation for Research and Treatment of Cancer Quality of life Questionnaire-C30 questionnaires, and to determine which of these two questionnaires may be considered more efficacious, in clinical practice, in describing the quality of life of patients with chronic pancreatitis. PATIENTS: We studied 163 consecutive patients with proven chronic pancreatitis. METHODS: The Italian version of the SF-12 Health Survey and the Italian neutral version of the European Organisation for Research and Treatment of Cancer Quality of life Questionnaire-C30 Version 3.0 questionnaires were administered. RESULTS: Pancreatic pain was the only clinical variable able to significantly impair the SF-12 Health Survey component summaries as well as all domains of the European Organisation for Research and Treatment of Cancer Quality of life Questionnaire-C30, while body mass index was positively related to the physical component summary-12 and to the domains of the European Organisation for Research and Treatment of Cancer Quality of life Questionnaire-C30. A high level of reliability of the domains/scores of the two questionnaires in evaluating the quality of life in patients with chronic pancreatitis was found and two main factors were identified. These two factors were mainly related to the two SF-12 Health Survey summary components. CONCLUSIONS: From a practical point of view, the SF-12 Health Survey is more reliable and easier to use in routine clinical practice than the European Organisation for Research and Treatment of Cancer Quality of life Questionnaire-C30.  相似文献   
78.
目的 探讨长期服用利培酮对精神分裂症患者生活质量的影响作用。方法 对 1997年 7月~ 2 0 0 0年 6月住院服用利培酮或氯氮平治疗达痊愈或显著进步、出院后回归社会达 18个月及以上的 174例精神分裂症患者 (利培酮 89例、氯氮平 75例 )的生活质量进行了分别于 2 0 0 0年 7月和 2 0 0 1年 7月进行了两次追踪随访对照研究。结果 第二次随访利培酮组患者的随访成功率高于氯氮平组 (χ2 =34.11,P <0 .0 0 0 1) ;利培酮组患者的生活质量两次随访结果均极显著高于氯氮平组 ,且利培酮组患者的生活质量较之一年前随访又有新的提高 ,多元逐步回归分析表明 :出院时服用药物剂量和种类是影响患者生活质量的较强因素。结论 利培酮能够提高精神分裂症患者的生活质量 ,远期疗效更突出  相似文献   
79.
This paper analyses the diverse services currently available for children under five in the UK, and considers the nature of the demand for them. It recounts the initiative made by Strathclyde Region to co-ordinate and integrate pre-five provision, administratively and at a service level. It then considers the efforts of other local authorities to integrate administratively and looks at some of the complexities of attempting to do so at a service level.  相似文献   
80.
Up to now, few analytical models have studied the incentives for cooperation in quality improvements among hospitals. Only those dealing with reimbursement systems have shown that, from the point of view of individual or competing hospitals, retrospective reimbursement is more likely to encourage quality improvements than prospective financing, while the reverse holds for efficiency improvements. This paper studies the incentives to improve the quality of hospital care, in an analytical model, taking into account the possibility of cooperative agreements, price besides non-price (quality) competition and quality improvements that may simultaneously increase demand, increase or reduce costs and spill over to rival hospitals. In this setting quality improvement efforts rise with the rate of prospective reimbursement, while the impact of the rate of retrospective reimbursement is ambiguous, but likely to be negative for quality improvements that are highly cost-reducting and create large spillovers. Cooperation may lead to more or less quality improvement than non-cooperative conduct, depending on the magnitude of spillovers and the degree of product market competition, relative to the net effect of quality on profits and the share of costs that is reimbursed retrospectively. Finally, the stability of cooperative agreements, supported by grim trigger strategies, is shown to depend upon exactly the opposite interaction between these factors.  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