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   31766篇
  免费   2579篇
  国内免费   74篇
耳鼻咽喉   546篇
儿科学   1253篇
妇产科学   1053篇
基础医学   4317篇
口腔科学   958篇
临床医学   2751篇
内科学   7343篇
皮肤病学   759篇
神经病学   3255篇
特种医学   998篇
外国民族医学   3篇
外科学   3907篇
综合类   560篇
一般理论   43篇
预防医学   2307篇
眼科学   637篇
药学   1770篇
中国医学   50篇
肿瘤学   1909篇
  2021年   429篇
  2020年   291篇
  2019年   471篇
  2018年   523篇
  2017年   376篇
  2016年   422篇
  2015年   470篇
  2014年   666篇
  2013年   982篇
  2012年   1294篇
  2011年   1353篇
  2010年   804篇
  2009年   688篇
  2008年   1229篇
  2007年   1327篇
  2006年   1317篇
  2005年   1239篇
  2004年   1239篇
  2003年   1128篇
  2002年   1195篇
  2001年   1097篇
  2000年   1167篇
  1999年   979篇
  1998年   365篇
  1997年   305篇
  1996年   320篇
  1995年   295篇
  1994年   288篇
  1993年   303篇
  1992年   862篇
  1991年   804篇
  1990年   683篇
  1989年   728篇
  1988年   677篇
  1987年   706篇
  1986年   650篇
  1985年   675篇
  1984年   536篇
  1983年   464篇
  1982年   300篇
  1980年   258篇
  1979年   456篇
  1978年   306篇
  1977年   257篇
  1976年   280篇
  1975年   266篇
  1974年   297篇
  1973年   294篇
  1972年   267篇
  1971年   260篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
OBJECTIVES: To test a possible association between the educational level (EL), cognitive performance, and neuropsychiatric features in Parkinson disease (PD). BACKGROUND: An inverse association has been reported between EL and cognitive dysfunction in patients with senile dementia of Alzheimer type but it is yet unsettled whether education has a similar effect on cognition in PD. METHODS: Seventy-two PD patients (45 males, mean age 68.7+/-11.6 y) underwent a detailed neurologic examination, a battery of neuropsychologic tests, and questionnaires for the evaluation of psychosis, sleep disturbances, and depression. According to the number of educational years, patients were divided into 3 groups: low EL (0 to 8 y), (15 patients), intermediate EL (9 to 12 y) (28 patients), and high EL (>/=13 y) (29 patients). RESULTS: Patients with a higher EL had a better cognitive function and an association was found between the patients' EL and their scores in various neuropsychologic tests mainly those sensitive to frontal lobe dysfunction. Low education was associated with an increased risk for hallucinations and a trend for more depression, delusions, and sleep disturbances. CONCLUSIONS: The association between high educational attainment and the lower risk of cognitive dysfunction suggest that education might modulate cognitive performance in PD.  相似文献   
23.
24.
Cerebellar involvement in motor and non-motor sequence learning was examined with serial reaction time tasks (SRT). Our sample consisted of 8 children and adolescents who had undergone surgical removal of a benign posterior fossa tumor (PFT) during childhood. None of them had undergone chemotherapy or cranial radiation therapy (CRT). Ages ranged from 1-11 years at surgery and 9-17 years at testing. The children were tested not earlier than 2.5 years after surgery (M = 5.9 years), enabling brain plasticity and recovery of functions. Their performance was compared with a matched control sample. The PFT group was not impaired in the implicit learning of sequences, as reflected in their performance in blocks with a repeated sequence, both before and after a random block. However, in the perceptual task, their performance deteriorated more than that of the control group when a random block was introduced, suggesting that it was more difficult for the patients to respond flexibly or change their response set when encountering changing task demands. These results are in line with another study by our group on task switching with the same patients.  相似文献   
25.
Hemifacial hypertrophy (HFH) is rare and characterized by unilateral enlargement of the head and teeth. Hemifacial hypertrophy is classified as true HFH (THFH) with unilateral enlargement of the viscerocranium, and partial HFH (PHFH) in which not all structures are enlarged. We present a case of THFH and compare and contrast it with a case of PHFH. Hemifacial hypertrophy may cover a wide spectrum of defects or may involve only muscle or bone. Myohyperplasia, reported previously as a separate syndrome, may actually represent a forme fruste of PHFH or THFH. The PHFH patient lead a healthy, normal life without significant psychosocial problems and was reluctant to accept his deformity. Contrastingly, the THFH patient had significant social stigma and compromised health together with major aesthetic morbidity. Treatment planning in THFH is arduous and involves multiple modalities. Therefore, it is imperative to differentiate THFH and PHFH for better understanding and management of the condition.  相似文献   
26.
27.
Ciprofloxacin treatment of typhus   总被引:4,自引:0,他引:4  
M Eaton  M T Cohen  D R Shlim  B Innes 《JAMA》1989,262(6):772-773
  相似文献   
28.
alpha 1- and beta-adrenoceptors were studied ex vivo in the brains of rats receiving repeated daily treatment with the standard antidepressant imipramine or the atypical antidepressant S-adenosyl-L-methionine (SAM), which has minimal effects on monoamine reuptake or turnover. Consistent with past studies, a decrease in the density of beta receptors at three weeks and an increase in the affinity of alpha 1 receptors for the agonist phenylephrine at one week of treatment was observed with imipramine. By comparison, an increase in the density of beta receptors and a decrease in the affinity of alpha 1 receptors for phenylephrine was observed at one week of treatment with SAM. These changes were no longer apparent at three weeks of treatment. The results suggest that treatment with SAM does lead to changes in adrenergic neurotransmission, but that down regulation of beta receptors or increased agonist affinity of alpha 1 receptors may not be necessary for the production of antidepressant effects.  相似文献   
29.
An early accurate diagnosis of subungual melanoma depends upon an alert podiatric physician. Clinically, the lesion is often easily misdiagnosed and mistreated because of its resemblance to benign nail conditions. This paper discusses the incidence, histology, clinical findings, diagnosis, and treatment of this malignant lesion. An illustrative case report is presented.  相似文献   
30.
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