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   11624篇
  免费   1086篇
  国内免费   113篇
耳鼻咽喉   213篇
儿科学   314篇
妇产科学   541篇
基础医学   1601篇
口腔科学   377篇
临床医学   1255篇
内科学   2590篇
皮肤病学   105篇
神经病学   1482篇
特种医学   385篇
外国民族医学   1篇
外科学   1535篇
综合类   221篇
一般理论   2篇
预防医学   670篇
眼科学   237篇
药学   677篇
中国医学   2篇
肿瘤学   615篇
  2021年   118篇
  2019年   129篇
  2018年   152篇
  2017年   136篇
  2016年   122篇
  2015年   154篇
  2014年   198篇
  2013年   333篇
  2012年   418篇
  2011年   454篇
  2010年   279篇
  2009年   292篇
  2008年   396篇
  2007年   489篇
  2006年   456篇
  2005年   459篇
  2004年   415篇
  2003年   384篇
  2002年   414篇
  2001年   368篇
  2000年   381篇
  1999年   289篇
  1998年   150篇
  1997年   146篇
  1996年   142篇
  1995年   105篇
  1994年   112篇
  1993年   102篇
  1992年   261篇
  1991年   257篇
  1990年   292篇
  1989年   293篇
  1988年   289篇
  1987年   281篇
  1986年   251篇
  1985年   279篇
  1984年   216篇
  1983年   165篇
  1982年   130篇
  1981年   136篇
  1979年   200篇
  1978年   158篇
  1977年   137篇
  1976年   114篇
  1975年   99篇
  1974年   160篇
  1973年   146篇
  1972年   117篇
  1971年   106篇
  1970年   108篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
Although medication-induced esophagitis is recognized more frequently nowadays, reports of associated radiographic findings are limited. Nine cases of esophagitis associated with various medications were evaluated by using double-contrast esophagography. The usual features were several discrete focal ulcerations localized to a short segment of the proximal half of the esophagus. In seven of the cases, the offending medication was an antibiotic. Symptoms resolved in about 4 days after medication was discontinued. Finding characteristic radiologic abnormalities in the appropriate clinical setting may obviate endoscopy.  相似文献   
23.
Role of CT in excluding major arterial injury after blunt thoracic trauma   总被引:2,自引:0,他引:2  
The role of CT in the diagnosis of major vascular rupture following blunt decelerating chest trauma is controversial. Its value in excluding major arterial injury has not yet been determined. During a 12-month period we obtained dynamic enhanced thoracic CT studies in 20 patients with blunt decelerating thoracic trauma who had abnormal or equivocal mediastinal contours on chest radiographs. In all cases diagnosis was confirmed by either digital subtraction (18 patients) or conventional thoracic angiography (two patients). CT scans showed evidence of direct aortic injury in three patients and evidence of mediastinal hematoma in five others. Four of these eight patients had major arterial injury verified angiographically and at surgery. In two patients the CT scan was considered equivocal; both patients had normal thoracic angiograms. CT excluded direct vascular injury or mediastinal hematoma in 10 patients. All 10 had normal thoracic angiograms. This preliminary study suggests that, in patients sustaining blunt decelerating thoracic trauma, thoracic CT may be more valuable than chest radiography in excluding major vascular injury and, in some cases, may reduce the need for thoracic angiography.  相似文献   
24.
The percentage of peripheral blood lymphocytes forming rosettes with sheep erythrocytes (E-rosettes) was determined in 33 severely malnourished Guatemalan children, and in two groups of clinically well but mildly growth retarded children from the same environment. Mean E-rosettes in the acutely ill patients was lower than the value observed in the mildly malnourished children, although there was considerable overlap between groups. These data differ from previously published studies of severely malnourished children from other parts of the world in that not all patients had decreased values for E-rosettes, in contrast to the uniform depression reported by others. As all patients were clinically similar, the results suggest that there may be specific nutrient defects associated with protein-energy malnutrition that particularly affect immune function. In addition, in vitro incubation of lymphocytes from the acutely malnourished children with the thymic factor, thymosin fraction 5, increased the percentage of E-rosettes in a dose-dependent fashion. These data suggest that immature, thymosin-responsive T cells are present in circulation. It is possible that in vivo thymosin administration may be beneficial for malnourished individuals.  相似文献   
25.
Chemotaxis, chemokinesis and cellular orientation were measured for unstimulated and 10(-7) n-formyl methionyl leucyl phenylalanine (F-met-leu-phe) stimulated polymorphonuclear leucocytes (PMNS) of nine patients with recent 10-80 per cent burns using a computer-assisted image analysis technique. The technique records PMN movement, as viewed with a phase-contrast microscope on videotapes, and then uses computer programs to calculate the speed and direction of up to 50 PMNS over a 5-min period. Orientation was determined visually. Cellular adherence was also measured by attachment methods. PMNS from burn patients were slower (av. speed 16.8 microns/min), responded less well to F-met-leu-phe (av. speed 20.9 microns/min, av. McCutcheon index 0.32), were less often oriented towards the chemoattractant (av. 39 per cent) and were more adherent (av. 50 per cent) than control cells (av. speed 21.8 microns/min; av. speed F-met-leu-phe 32.2 microns/min; McCutcheon index 0.61; oriented 59 per cent adherent; 16 per cent). Thus PMNS from burn patients orient less well, are significantly slower and have less directionality in response to a chemoattractant, and are more adherent suggesting activation.  相似文献   
26.
27.
PURPOSE: Acute pain management services (APMS) evolved in response to the desire for improved management of postoperative pain. The management of postoperative pain received formal support from international organizations over the past decade and by 1993 half of the Canadian university-affiliated teaching hospitals had implemented an APMS. The purpose of this survey was to describe APMSs in Canadian academic institutions, with specific emphasis on postoperative analgesics, new analgesic methods, training and research. METHODS: Between June 2000 and January 2001, 62 Canadian hospitals affiliated with the 16 Canadian university anesthesiology departments were sent a postal questionnaire. RESULTS: Fifty of the 62 respondents returned a completed questionnaire representing a response rate of 81%. Eighty percent of the hospitals surveyed had at least 200 beds, 90% (45) had implemented an APMS. Anesthesiology was primarily responsible in all 45 hospitals with an APMS. The results presented are based on the 45 centres with an APMS. CONCLUSION: Since the early 1990s the percent of Canadian academic hospitals with an APMS has increased from 53% to 92%. These figures are comparable to the United States. Greater collaboration from nursing and pharmacy, mandatory training for medical and nursing students and residents, and a standardized approach to continuous quality improvement remain necessary.  相似文献   
28.
Nutritional dwarfing refers to a condition in which maladaptive eating patterns play a primary role in poor linear growth and delayed pubertal development. The present controlled study assesses whether nutritionally dwarfed children and adolescents differ in their psychosocial adjustment from healthy children and adolescents of comparable height in ways that might account for their undernutrition. Children with nutritional dwarfing (n = 16) were compared by standardized questionnaires with a short-stature (ie, heights below the fifth percentile) control group composed of children and adolescents with constitutional growth delay and/or familial short stature (n = 31). Scores on a self-report screening questionnaire for eating disorders did not differentiate the groups. Moreover, the vast majority of nutritionally dwarfed patients expressed a desire to have a heavier physical appearance. Whereas the groups were generally similar in self-perceptions of domain-specific competencies and positive psychosocial adjustment, the parents of nutritionally dwarfed children reported that their children showed significantly fewer externalized behavior problems. These findings suggest the existence of an eating disturbance that compromises growth in childhood and/or adolescence which, unlike anorexia nervosa, is not associated with evidence of psychopathology.  相似文献   
29.
30.
Patients who had undergone unilateral temporal lobe surgery (right or left temporal lobectomy or amygdalo-hippocampectomy) for intractable temporal lobe epilepsy, and normal control subjects, completed two questionnaires about everyday memory, the Subjective Memory Questionnaire (SMQ) and the Everyday Memory Questionnaire (EMQ). Relatives/close friends completed suitably adapted versions of these questionnaires about the patient. Patients who had undergone right and left temporal lobectomy rated themselves, and were rated by relatives/friends as having worse memories than controls on both the SMQ and EMQ. Individual items on both questionnaires differentiated between the memory abilities of the five groups. Age at surgery was correlated with one measure of everyday memory for the right temporal lobectomy group, and seizure frequency was correlated with memory performance for the amygdalo-hippocampectomy groups. Issues concerning validity and accuracy of rating memory lapses are discussed.  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