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   814篇
  免费   48篇
耳鼻咽喉   4篇
儿科学   25篇
妇产科学   30篇
基础医学   70篇
口腔科学   11篇
临床医学   104篇
内科学   211篇
皮肤病学   31篇
神经病学   31篇
特种医学   9篇
外科学   155篇
综合类   38篇
一般理论   1篇
预防医学   48篇
眼科学   16篇
药学   59篇
肿瘤学   19篇
  2017年   8篇
  2016年   8篇
  2015年   7篇
  2014年   14篇
  2013年   16篇
  2012年   5篇
  2011年   6篇
  2010年   14篇
  2009年   11篇
  2008年   6篇
  2006年   7篇
  1999年   9篇
  1998年   14篇
  1997年   22篇
  1996年   24篇
  1995年   27篇
  1994年   18篇
  1993年   30篇
  1992年   16篇
  1991年   15篇
  1990年   17篇
  1989年   19篇
  1988年   13篇
  1987年   20篇
  1986年   21篇
  1985年   9篇
  1984年   10篇
  1983年   16篇
  1982年   14篇
  1980年   8篇
  1979年   6篇
  1978年   5篇
  1977年   10篇
  1976年   6篇
  1972年   7篇
  1968年   4篇
  1967年   5篇
  1964年   4篇
  1963年   7篇
  1961年   4篇
  1960年   5篇
  1959年   39篇
  1958年   44篇
  1957年   52篇
  1956年   53篇
  1955年   53篇
  1954年   32篇
  1949年   16篇
  1948年   23篇
  1946年   5篇
排序方式: 共有862条查询结果,搜索用时 0 毫秒
1.
To determine whether fetal and infant growth could influencesusceptibility to autoimmune disease in adults, the occurrenceof thyroid autoantibodies and autoimmune thyroiditis was studiedin 305 women, aged 60–71, born in Hertfordshire and forwhom details of birth weight, infant growth, and feeding wereroutinely recorded. Thyroglobulin autoantibody was detectedin 37% of the women, thyroid peroxidase autoantibody in 41%,and autoimmune thyroiditis, defined as biochemical or clinicalhypothyroidism in association with thyroid autoantibodies, in5.6%. The proportion of women with thyroglobulin and thyroidperoxidase auto antibodies fell with increasing birth weightbut was not related to weight at 1 year of age or the methodof infant feeding. The prevalence of both autoantibodies rosewith increasing adult body mass index but fell as the waistto hip ratio increased. These results demonstrate the importance of early environmentin determining the susceptibility to autoimmune thyroid disease.The contrasting effects of adult body mass index and waist tohip ratio on antibody prevalence could be explained by theirassociations with different hormonal environments.  相似文献   
2.
3.
4.
5.
Selecting a population of spermatozoa by the swim-up technique yields, after freezing and thawing, a population of cells that contains proportionally more spermatozoa which are morphologically normal, fewer spermatozoa with damaged tail membranes, and a greater percentage of progressively motile spermatozoa with greater velocities and amplitudes of head displacement than those obtained after freezing and thawing the same semen samples in the normal way. This pattern was found for the semen from 10 patients and five volunteers. However, the cells selected by swim-up were as susceptible to the stresses caused by freezing and thawing as unselected spermatozoa in the original semen sample, and the improvement came from the better quality of the initial sample.  相似文献   
6.
7.
Extracorporeal membrane oxygenation (ECMO) is increasingly used to support postcardiotomy cardiorespiratory failure in children with congenital heart disease. We report on survival outcomes and factors associated with survival for postcardiotomy ECMO patients.  相似文献   
8.
We have studied the onset and duration of action and pharmacokineticsof rocuronium bromide (Org 9426) during anaesthesia with nitrousoxide, fentanyl and isoflurane after a single bolus dose ofrocuronium 0.6 mg kg–1 in nine patients with chronic renalfailure requiring regular haemodialysis, and in nine healthycontrol patients. Blood samples were collected over 390 minand concentrations of rocuronium and its putative metabolitesmeasured using HPL C. Onset time for maximum block, durationof clinical relaxation (T125) and recovery index, were 61 (SD25.0) s and 65 (16.4) s, 55 (26.9) min and 42 (9.3) min and28 (12.3) min and 19 (8.8) min, respectively, for patients withand without renal failure. The time for TOF ratio to returnspontaneously to 0.7 was 99 (41.1) min and 73 (24.2) min, respectively,in the two groups. None of these differences was significant.The pharmacokinetic data were best described by a three-exponentialequation. There were significant differences between patientswith and without renal failure in the rates of clearance (2.5(1.1) ml kg–1 min–1 and 3.7(1.4) ml kg–1 min–1respectively) and the mean residence times (97.1 (48.7) minand 58.3(9.6) min) (P<0.05). The differences in other kineticparameters were not significant. We conclude that the effectsof rocuronium may be prolonged in patients with renal disease,because of a decreased clearance of the drug.  相似文献   
9.
Prior research indicates that alcohol-related outcome expectancies represent important etiological factors in the understanding of alcohol use/abuse. Although current multidimensional measures assess several substantively different domains of alcohol-related outcome expectancies, there is growing evidence that they may not possess adequate levels of discriminant validity. Therefore, the present study sought to examine whether reliable between-person differences exist in the ability to differentiate among alcohol expectancy domains. The focus of the study was on three sets of intrapersonal characteristics: cognitive resources, cognitive constraints, and alcohol-related experience. Data were collected via household interviews with a random sample of 1125 adults. Multiple regression analysis revealed that higher levels of cognitive resources were associated with increasing levels of differentiation among alcohol expectancy domains. Results are discussed in terms of implications for the development of new or revised multidimensional alcohol expectancy questionnaires. Directions for future research are also discussed.  相似文献   
10.
IS THE HIP INVOLVED IN GENERALIZED OSTEOARTHRITIS?   总被引:1,自引:1,他引:0  
Elbow pain is a common complaint and elbow hyperostosis a frequentradiological condition. However, little is known about the associationbetween the clinical and radiological findings. To evaluatethe relationship between spinal and extraspinal hyperostoticfeatures and the clinical relevance of elbow hyperostosis wehave performed the first controlled, double-blinded study of85 hospitalized probands, 33 with and 52 without thoracospinalhyperostosis on lateral chest X-ray. Elbow and shoulder hyperostosiswere graded on bilateral standard radiographs. Elbow pain wasassessed by an interviewer using a standardized questionnaireand extraskeletal causes of elbow pain were recorded. The prevalenceof elbow hyperostosis was increased in cases with thoracospinalhyperostosis compared to controls (82% versus 58%, X2 = 5.32,P<0.025, n = 85, odds ratio (OR) 3.30 (95% Cl 1.16–9.35)).Similarly, the prevalence of elbow hyperostosis was increasedin cases with shoulder hyperostosis compared to controls (83%versus 60%, x2 = 4.51, P<0.05, n = 84, OR = 3.20 (95% CI1.06–9.66)), emphasizing the multifocal nature of hyperostoticfeatures. Elbow pain was only slightly more prevalent in caseswith elbow hyperostosis compared to controls (21% versus l3%,x2 = 0.75, NS, OR = 1.84 (95% CI 0.46–7.44)). We concludethat elbow hyperostosis is a radiological finding of doubtfulclinical relevance. KEY WORDS: Hyperostosis, Spinal osteophytosis, Elbow, Pain  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