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   28999篇
  免费   2354篇
  国内免费   31篇
耳鼻咽喉   348篇
儿科学   1046篇
妇产科学   682篇
基础医学   3467篇
口腔科学   578篇
临床医学   3713篇
内科学   5355篇
皮肤病学   440篇
神经病学   2781篇
特种医学   1242篇
外科学   3604篇
综合类   663篇
一般理论   46篇
预防医学   3178篇
眼科学   506篇
药学   2149篇
  3篇
中国医学   41篇
肿瘤学   1542篇
  2021年   399篇
  2020年   235篇
  2019年   347篇
  2018年   417篇
  2017年   300篇
  2016年   361篇
  2015年   412篇
  2014年   616篇
  2013年   930篇
  2012年   1176篇
  2011年   1340篇
  2010年   765篇
  2009年   567篇
  2008年   1165篇
  2007年   1282篇
  2006年   1279篇
  2005年   1199篇
  2004年   1182篇
  2003年   1028篇
  2002年   971篇
  2001年   965篇
  2000年   980篇
  1999年   777篇
  1998年   314篇
  1997年   297篇
  1996年   260篇
  1995年   278篇
  1994年   242篇
  1993年   227篇
  1992年   692篇
  1991年   706篇
  1990年   665篇
  1989年   636篇
  1988年   615篇
  1987年   577篇
  1986年   595篇
  1985年   559篇
  1984年   439篇
  1983年   430篇
  1982年   282篇
  1981年   269篇
  1980年   243篇
  1979年   432篇
  1978年   322篇
  1977年   280篇
  1976年   252篇
  1975年   241篇
  1974年   299篇
  1973年   261篇
  1972年   233篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Cytomegalovirus (CMV) was recovered from a 5-month-old infant with probable congenital infection. In life, no hearing impairment had been observed. Auditory brain stem evoked responses were bilaterally intact. At necropsy, both temporal bones were morphologically normal, as demonstrated by light and electron microscopy. Sensory hair cells of the organ of Corti appeared intact. Cytomegalovirus was recovered from a mixture of perilymph and endolymph, but not the brain, CSF, or vitreous humor. This appears to be the first report of an individual with an inner ear CMV infection in which neither structural nor functional alterations of the inner ear were apparent. This case also suggests that CMV can persist within the inner ear for prolonged periods following congenital infection.  相似文献   
102.
Cross-sectional analysis of four general representative populations of middle-aged adults in the United States in 1986-1989 provides estimates of the close relation of high density lipoprotein cholesterol (HDL cholesterol) to its major structural apolipoprotein (apolipoprotein A-I) and to fasting plasma triglyceride levels. HDL cholesterol differences of approximately 0.4 mg were associated with 1-mg differences in apolipoprotein A-I; differences of 20% in HDL cholesterol (reductions) were associated with triglyceride doublings. Variation in apolipoprotein A-I and triglyceride concentration together accounted for 66% of the population variance in HDL cholesterol. The uniformity of this pattern in the four race-sex groups studied suggests an important role of triglyceride-cholesterol transfer as a determinant of HDL cholesterol. The fundamental relations observed among HDL cholesterol, apolipoprotein A-I, and triglycerides were unaltered by levels of factors under personal volition. The volitional factors appeared to influence HDL cholesterol indirectly: Obesity and physical activity were affected primarily through their associations with triglycerides, and alcohol use and smoking through associations with apolipoprotein A-I. The association of alcohol use with elevated HDL cholesterol was attenuated in persons with greater body mass.  相似文献   
103.
The treatment of persistent psychogenic cough, a potentially debilitating condition among pediatric patients, can pose diagnostic and treatment dilemmas. Its treatment by the use of a procedure called reinforced suggestion technique was described previously. The use of an alternative procedure relying upon parental and self-monitoring of coughing and either social or material rewards for decreasing rates of coughing is presented.  相似文献   
104.
105.
106.
107.
Using purified enzyme preparations, we investigated the actions of angiotensin-converting enzyme, aminopeptidase N, and endopeptidase 24.11 on corticotropin-releasing factor (CRF). The effects of inhibition of these enzymes on CRF action in rat anterior pituitary cultures were also determined. Finally, specific inhibitors were used to evaluate ectopeptidase action on the regional brain metabolism of CRF. K(m) values for CRF were 165, 90, and 42 microM for angiotensin-converting enzyme, aminopeptidase N, and endopeptidase 24.11, respectively. A CRF metabolite profile for each enzyme was determined. In pituitary cultures, inhibition of endopeptidase 24.11 and aminopeptidase N potentiated CRF-stimulated release of adrenocorticotropic hormone (ACTH). In rat pituitary and hypothalamus membrane preparations, specific inhibitor experiments indicated that CRF hydrolysis involved members of the neutral endopeptidase and aminopeptidase enzyme families. In cortex membranes, similar peptidase inhibition was without effect. These data support the hypothesis that ectopeptidases play a major role in CRF metabolism and biological function.  相似文献   
108.
The α-inhibin gene has been shown in knockout mouse models to be a suppressor of granulosa tumorigenesis in the mouse. To determine if α-inhibin has the same function in humans, we have assessed the frequency of loss of heterozygosity (LOH) of the α-inhibin gene locus on chromosome 2q in 17 human granulosa cell tumors and 36 epithelial ovarian cancers. LOH was detected in 12 of 36 (33.3%) epithelial tumors but in only 1 of 17 (6%) granulosa cell tumors. These data suggest that in contrast to the suggestions from the mouse model α-inhibin does not function as a granulosa cell tumor suppressor gene in the human. Furthermore, analysis of the TP53 gene in the granulosa cell tumors failed to detect either LOH or point mutations, indicating that they have a developmental pathway distinct from that of epithelial ovarian tumors.  相似文献   
109.
The asymptomatic patient with suspected myocardial contusion   总被引:4,自引:0,他引:4  
Diagnostic criteria and guidelines for hospital admission for suspected myocardial contusion (MCC) remain unclear. This study defines and examines the clinical sequelae of patients admitted with a suspicion of MCC. Criteria for observation following isolated, minor blunt chest trauma are suggested. Hospital and trauma registry records of patients admitted over a 33-month period with suspected MCC were reviewed. Conventional evaluation criteria, cardiac-related complications, and associated injuries were analyzed for 524 patients. Twenty-eight cardiac-related complications occurred in 27 of 524 patients (5%). These complications included 23 dysrhythmias, 3 infarctions, and 2 pericardial effusions. There were 23 patients with abnormal admission electrocardiograms and 4 with normal ones. Of the latter, one patient developed dysrhythmia 4 hours after admission, and three had other major multi-system injuries requiring admission to the intensive care unit. The overall incidence of cardiac-related complications in minimally injured patients was 0.1%. There were no complications in patients with isolated chest wall contusions, a normal admission electrocardiogram, and a normal rhythm at 4 hours. There was no significant association between creatine phosphokinase isoenzymes or echocardiogram and cardiac-related complications. The complete absence of significant cardiac sequelae in patients with isolated chest wall contusion, normal admission and 4-hour electrocardiograms, and no other associated major injuries suggests that these patients need not be admitted.  相似文献   
110.
Lipodermatosclerosis: review of cases evaluated at Mayo Clinic.   总被引:1,自引:0,他引:1  
BACKGROUND: Lipodermatosclerosis describes bound-down, sclerotic skin involving the lower extremities. OBJECTIVE: Our purpose was to describe the demographic and clinical features of patients with lipodermatosclerosis. METHODS: This was a retrospective study of patients presenting to Mayo Clinic between 1976 and 1998 with a diagnosis of lipodermatosclerosis. RESULTS: Of 97 patients, 84 (87%) were women. Mean age was 62 years (range, 25-88 years). Mean body mass index was 34.3 (range, 17.8-71.5). Clinical signs were bilateral involvement in 44 patients (45%), induration localized to a discrete plaque in 49 (51%), erythema in 69 (71%), hyperpigmentation in 57 (59%), ulceration in 13 (13%), concomitant edema in 69 (71%), and varicosities in 55 (57%). Vascular studies performed on 72 patients showed abnormalities in 49: deep venous incompetence in 33 (67%), calf muscle pump abnormality in 19 (39%), abnormal pulsatility in 10 (20%), and obstruction in 1 (2%). CONCLUSION: Lipodermatosclerosis was associated with female sex, middle age, high body mass index, and venous abnormalities.  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