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   1601632篇
  免费   131497篇
  国内免费   2581篇
耳鼻咽喉   21646篇
儿科学   52934篇
妇产科学   46225篇
基础医学   227761篇
口腔科学   47199篇
临床医学   140903篇
内科学   314756篇
皮肤病学   34091篇
神经病学   130101篇
特种医学   64721篇
外国民族医学   474篇
外科学   243793篇
综合类   39712篇
现状与发展   3篇
一般理论   544篇
预防医学   122857篇
眼科学   36471篇
药学   121256篇
  3篇
中国医学   2974篇
肿瘤学   87286篇
  2018年   14764篇
  2016年   12898篇
  2015年   15025篇
  2014年   20645篇
  2013年   31350篇
  2012年   42545篇
  2011年   44750篇
  2010年   26335篇
  2009年   25302篇
  2008年   42995篇
  2007年   45239篇
  2006年   46048篇
  2005年   44673篇
  2004年   44088篇
  2003年   42178篇
  2002年   41289篇
  2001年   75681篇
  2000年   78325篇
  1999年   66387篇
  1998年   17731篇
  1997年   16334篇
  1996年   16314篇
  1995年   16019篇
  1994年   15070篇
  1993年   14217篇
  1992年   55428篇
  1991年   53775篇
  1990年   52561篇
  1989年   50833篇
  1988年   47221篇
  1987年   46560篇
  1986年   44284篇
  1985年   42844篇
  1984年   32033篇
  1983年   27566篇
  1982年   16145篇
  1981年   14436篇
  1980年   13564篇
  1979年   30460篇
  1978年   21064篇
  1977年   17764篇
  1976年   16694篇
  1975年   17574篇
  1974年   21486篇
  1973年   20673篇
  1972年   18853篇
  1971年   17770篇
  1970年   16289篇
  1969年   15268篇
  1968年   13949篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
We examined several possible causes for the high incidence of poor sensory acuity in the limbs of 176 patients with moderate to severe peripheral vascular insufficiency. We investigated the relationships of diabetes, alcoholism, and smoking, as well as the severity of peripheral vascular disease, to the integrity of basic sensory modalities such as two-point discrimination and perception of light touch. The presence or absence of diabetes exerted the strongest effect on peripheral sensation. In patients who did not have diabetes, sensation in the limbs was most strongly affected by whether the patient was an alcoholic. Smoking did not have a significant effect on limb sensation. Among nondiabetic, nonalcoholic patients, there was a weak residual effect related to the severity of the peripheral vascular insufficiency. Even among these patients, however, systemic factors predominated in determining the loss of sensation. We also examined the extent to which loss of sensation might be related to the development of ulcers. Among patients who were not diabetic, there was a highly significant relationship between loss of sensation and the presence of limb ulceration. Surprisingly, however, there was no discernable relationship between the presence of ulcers in diabetic patients and the degree of loss of peripheral sensation. This result suggests that a large percentage of ulcers seen in diabetic patients are not of neurogenic origin.  相似文献   
952.
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   
953.
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   
954.
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   
955.
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   
956.
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   
957.
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   
958.
959.
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   
960.
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