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   1603998篇
  免费   131695篇
  国内免费   2581篇
耳鼻咽喉   21664篇
儿科学   53054篇
妇产科学   46267篇
基础医学   228002篇
口腔科学   47257篇
临床医学   141222篇
内科学   315267篇
皮肤病学   34108篇
神经病学   130264篇
特种医学   64800篇
外国民族医学   474篇
外科学   244215篇
综合类   39762篇
现状与发展   3篇
一般理论   544篇
预防医学   123114篇
眼科学   36495篇
药学   121394篇
  3篇
中国医学   2976篇
肿瘤学   87389篇
  2018年   14803篇
  2016年   12915篇
  2015年   15062篇
  2014年   20691篇
  2013年   31423篇
  2012年   42659篇
  2011年   44862篇
  2010年   26419篇
  2009年   25350篇
  2008年   43117篇
  2007年   45375篇
  2006年   46174篇
  2005年   44797篇
  2004年   44230篇
  2003年   42312篇
  2002年   41397篇
  2001年   75782篇
  2000年   78409篇
  1999年   66451篇
  1998年   17752篇
  1997年   16360篇
  1996年   16337篇
  1995年   16041篇
  1994年   15089篇
  1993年   14226篇
  1992年   55477篇
  1991年   53807篇
  1990年   52592篇
  1989年   50875篇
  1988年   47261篇
  1987年   46595篇
  1986年   44314篇
  1985年   42867篇
  1984年   32057篇
  1983年   27589篇
  1982年   16167篇
  1981年   14454篇
  1980年   13572篇
  1979年   30489篇
  1978年   21088篇
  1977年   17772篇
  1976年   16701篇
  1975年   17586篇
  1974年   21505篇
  1973年   20688篇
  1972年   18871篇
  1971年   17783篇
  1970年   16295篇
  1969年   15276篇
  1968年   13959篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
Survey involved 84 workers matched for age, socio-occupational and families status and divided into 3 groups : A : 27 shift workers on 3 days rotating shift, B : 47 shift workers on 5 days rotating shift, C : 20 days workers. Each subject was submitted to dietary survey by means of 24 hours recall, realised 3 times for shift workers and once for control. All workers were interviewed about caloric intake of the preceding day off caloric intake. Annual weight gain was studied through the use of occupational health service records. There was no significant difference between the 3 groups for working day caloric intake. Day-off intake was lower (p less than 0.05) in group A (day-off any day of the week). Annual weight gain was not different between the 3 groups. Shift workers with faster weight gain had a higher caloric intake on day-off and after evening meal.  相似文献   
952.
Obsessive-compulsive disorder is increasingly recognized in patients of different age groups. Serotonergic agents, such as clomipramine, have been recently found to be useful in the management of this condition. However, unexpected side effects, such as dysphoria, aggressiveness, and paranoid ideation, may occur with therapeutic doses of this compound, as evidenced in the cases of two male adolescents presented here. Possible pathogenetic factors, involving serotonin and serotonin-receptor abnormalities are discussed. Management of these side effects is based on adequate dose reduction and monitorization.  相似文献   
953.
It is estimated that there are currently 10 million women in the United States who are taking oral contraceptives on a daily basis. Although the actual number is not known, it is also estimated that a large number of these same women are on concomitant drug therapy. In recent years, there has been a number of published reports linking a loss of contraceptive efficacy with the concurrent administration of other drugs, including antibiotics. Because of the common practice of prescribing antibiotics in dentistry, oral healthcare providers should be aware of the possibility of oral contraceptive failure with antibiotic treatment. Since it is often the dental hygienist who interviews patients and assists them in completing their health questionnaire, she or he can play an important role in educating and counseling these patients in possible drug interactions. This article reviews the published incidence of oral contraceptive/antibiotic interaction, along with a discussion of the possible mechanisms by which this interaction occurs. Recommendations are also presented for the oral health management of women taking oral contraceptives and other prescribed drugs.  相似文献   
954.
Coexistent primary hyperparathyroidism and monoclonal gammopathy, although rare, has been reported previously by a number of investigators. We report four patients with such an occurrence who were seen between 1976 and 1988. Another patient with primary hyperparathyroidism also had multiple myeloma and was in remission for 12 years. These patients represent approximately 1% of the 386 patients with primary hyperparathyroidism seen during the same 12-year period. Although several mechanisms have been proposed to explain this concurrence, we believe it is the result of a chance occurrence. A review of the literature, an estimate of the chance occurrence of coincidental monoclonal gammopathy, benign or malignant, in patients with primary hyperparathyroidism, and some practical implications of this interesting coexistence are presented.  相似文献   
955.
Encephalo-myelo-radiculo-ganglionitis presenting as pandysautonomia   总被引:2,自引:0,他引:2  
A 68-year-old man developed pandysautonomia with severe orthostatic dysfunction, fixed heart rate, low serum levels of norepinephrine and epinephrine, absent sympathetic skin responses, and pupillary abnormalities. CSF protein was 92 mg/dl. In spite of a good recovery following corticosteroid administration, a relapse occurred, with accompanying sensory symptoms confined to both arms. Fatal sudden cardiac arrest occurred after 4 months. Autopsy revealed numerous lymphocytic infiltrates, predominantly in autonomic and sensory ganglia and, to a lesser extent, in the nerve roots, spinal cord, and brainstem without evidence for an underlying tumor. This case provides histopathologic evidence for an inflammatory etiology of panautonomic neuropathy in some patients.  相似文献   
956.
We conducted a randomized, double-blind, crossover trial of two anticholinergic agents--trihexyphenidyl and tridihexethyl chloride (a quaternary anticholinergic that does not cross the blood-brain barrier)--in patients with acquired nystagmus and measured visual acuity and nystagmus before and at the end of 1 month on each medication. Of the 10 patients admitted to the study, only five completed trials of both drugs due to intolerance of medication or intercurrent illness. Of six patients who completed the trial of trihexyphenidyl, only one showed improvement. Of six patients who completed a trial of tridihexethyl chloride, four showed improvement. We conclude that (1) trihexyphenidyl is not a reliable treatment for acquired nystagmus, although occasional patients may benefit; (2) anticholinergic agents may suppress nystagmus by peripheral rather than central mechanisms; and (3) the side effects of anticholinergic agents limit their effectiveness in the treatment of nystagmus.  相似文献   
957.
958.
Data obtained on a sample of persons with mild to profound degrees of mental retardation (N = 8255) and ranging from birth to 98 years of age were factor analyzed to provide information on the structure of maladaptive behavior relative to age and degree of mental retardation. Using the Problem Behavior scales of the Inventory for Client and Agency Planning, two principal factors emerged for children with mild to profound degrees of retardation: Internalized Maladaptive and Externalized Maladaptive. For adolescents and young adults, a three-factor solution which varied by degree of retardation was most appropriate. For middle and older adults, three- and four-factor solutions were identified across all ages and degrees of retardation. Across all samples as many as six different types of dimensions were identified, indicating that the structure of maladaptive behavior may well be influenced by age and level of mental retardation.  相似文献   
959.
960.
The efficacy of intravenous thrombolytic agents in preserving left ventricular function and in decreasing mortality from an acute myocardial infarction was demonstrated in the 1980s. The 1990s will concentrate on adjunctive therapy to thrombolysis in the treatment of an acute myocardial infarction.  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