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   18882篇
  免费   1805篇
  国内免费   43篇
耳鼻咽喉   163篇
儿科学   502篇
妇产科学   336篇
基础医学   2782篇
口腔科学   408篇
临床医学   2230篇
内科学   4009篇
皮肤病学   436篇
神经病学   1530篇
特种医学   504篇
外科学   3210篇
综合类   407篇
一般理论   13篇
预防医学   1625篇
眼科学   271篇
药学   1298篇
中国医学   15篇
肿瘤学   991篇
  2021年   257篇
  2020年   189篇
  2019年   288篇
  2018年   275篇
  2017年   266篇
  2016年   286篇
  2015年   304篇
  2014年   419篇
  2013年   595篇
  2012年   956篇
  2011年   915篇
  2010年   490篇
  2009年   497篇
  2008年   783篇
  2007年   836篇
  2006年   833篇
  2005年   829篇
  2004年   768篇
  2003年   760篇
  2002年   696篇
  2001年   571篇
  2000年   672篇
  1999年   533篇
  1998年   233篇
  1997年   207篇
  1996年   199篇
  1995年   165篇
  1994年   159篇
  1993年   168篇
  1992年   487篇
  1991年   463篇
  1990年   404篇
  1989年   401篇
  1988年   396篇
  1987年   367篇
  1986年   360篇
  1985年   328篇
  1984年   320篇
  1983年   225篇
  1982年   147篇
  1981年   146篇
  1980年   136篇
  1979年   265篇
  1978年   163篇
  1977年   132篇
  1976年   138篇
  1974年   168篇
  1973年   167篇
  1972年   157篇
  1971年   123篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
31.
32.
S P Caudill  S J Smith  G R Cooper 《Statistics in medicine》1989,8(3):295-309; discussion 331-2
Using data from the National Health and Nutrition Examination Survey (NHANES II) 1976-1980, we demonstrate how cross-sectional total serum cholesterol surveillance data can be used by an individual to assess current and future personal cholesterol risk status. We propose statistical models, based on a person's current measured cholesterol level and the relationship between cross-sectional age and cholesterol percentile estimates, that will allow prediction of future cholesterol levels or the age at which specified cholesterol risk levels will be reached if no cholesterol-altering intervention is taken. These models incorporate the observed variation in the NHANES II data and expected intraperson biological variation and intralaboratory analytical variation. We illustrate the adequacy of the models using data from the longitudinal Framingham Study.  相似文献   
33.
This paper reports on five families whose parents described the stress arising from their child's disability and the additional stress and reward of participation in a Conductive Education program. The reports support the Conductive Education thesis, that children with physical disabilities respond well to integrated management which weaves medical insights and therapeutic practice into the fabric of daily life through a program which has an educational rather than a therapeutic bias. Parents also appreciate personal support from a non-intimidating, professionally comprehensive resource. An attempt was made to identify the elements which produced parental self-confidence and family cohesion.  相似文献   
34.
Troponin T levels have been monitored in baboons (n = 8) undergoing pig heterotopic heart transplantation, and correlated with a decrease in graft contractions and graft survival. Pig heart graft survival was from 12 to 139 days (mean 45, median 33), and graft failure was associated with predominant thrombotic microangiopathy and ischemia, with focal hemorrhage, and edema. An increase in troponin T levels 5 to 6 days before graft failure correlated closely with diminished graft contractions. An increase in troponin T was a reliable indicator that graft dysfunction was occurring.  相似文献   
35.
Complications associated with the use of the GlideScope® videolaryngoscope   总被引:1,自引:0,他引:1  
PURPOSE: Two cases are presented wherein the GlideScope videolaryngoscope (GVL) facilitated laryngeal exposure and successful endotracheal intubation, but resulted in pharyngeal injury. CLINICAL FEATURES: GlideScope videolaryngoscopy was performed in two female patients, whose airways were anticipated to present difficulties for direct laryngoscopy. In the first case, following induction of anesthesia, moderate difficulty was encountered in directing the endotracheal tube (ETT) into the patient's larynx. In the second case, minimal difficulty with the GVL was experienced, and no problems were identified with airway instrumentation until the drapes covering the patient's face were removed. In both instances, the ETT had passed through the right palatopharyngeal arch, requiring suturing in the first patient, and electrocautery in the second patient. CONCLUSION: There have been no previously published reports of injuries related to GlideScope laryngoscopy, but perforation of the palatopharyngeal arch occurring in two patients demonstrates a rare but potentially important complication of the GVL. Strategies to minimize this complication are considered.  相似文献   
36.
37.
Repeated measures designs are often used to evaluate the effectiveness of interventions. In these designs, the outcomes are measured on several occasions before and after implementation of the intervention. Two statistical methods, the repeated measures analysis of variance (RM-ANOVA) and hierarchical linear models (HLM), can be used to analyze the data. The authors provide an overview of the statistical models underlying RM-ANOVA and HLM and discuss the strengths and limitations of each. They propose that the 2 methods are complementary in determining the effectiveness of interventions.  相似文献   
38.
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   
39.
The purpose of this study was to determine the relationship between selected anthropometric and physiological variables and 10K time. Eleven male wheelchair athletes with spinal cord injuries in training for national competition performed continuous progressive exercise tests on a wheelchair ergometer to determine maximal metabolic and cardiorespiratory values. Anthropometric data were also collected. The laboratory data were analyzed for correlation with the best 10K time of each subject during the test period. The subjects averaged 27 min 30 sec for their 10K races, 2.49 L.min-1 for VO2max and 35 percent for maximal gross mechanical efficiency during submaximal exercise. Speed at peak oxygen consumption (r = -0.66), gross mechanical efficiency (r = -0.56), and body density (r = -0.57) was found to be significantly (p less than 0.10) correlated with 10K time. The results show very little correlation between VO2max and 10K time (r = 0.02). Further study is indicated for the relationship between gross mechanical efficiency, speed at maximal oxygen consumption, body density, and 10K time; these variables may be useful in evaluating training programs for improving race performance.  相似文献   
40.
PURPOSE: To describe the clinical use of a new videolaryngoscope in a patient who had repeatedly been difficult or impossible to intubate by conventional direct laryngoscopy. This device provided excellent glottic visualization and permitted easy endotracheal intubation. CLINICAL FEATURES: A 74-yr-old male presenting for repeat elective surgery had a history of failed intubations by direct laryngoscopy and pulmonary aspiration with a laryngeal mask airway. He refused awake flexible fibreoptic intubation. After the induction of general anesthesia, laryngoscopy was performed using a GlideScope. This provided complete glottic exposure and easy endotracheal intubation. CONCLUSION: This new videolaryngoscope provided excellent laryngeal exposure in a patient whom multiple experienced anesthesiologists had repeatedly found to be difficult or impossible to intubate using direct laryngoscopy. The clinical role of this device awaits confirmation in a large series of difficult airways.  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