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   666篇
  免费   20篇
  国内免费   67篇
耳鼻咽喉   1篇
儿科学   25篇
妇产科学   8篇
基础医学   63篇
口腔科学   8篇
临床医学   89篇
内科学   75篇
皮肤病学   13篇
神经病学   155篇
特种医学   154篇
外科学   19篇
综合类   27篇
预防医学   35篇
眼科学   1篇
药学   58篇
肿瘤学   22篇
  2022年   4篇
  2021年   11篇
  2020年   2篇
  2019年   5篇
  2018年   5篇
  2017年   3篇
  2016年   6篇
  2015年   9篇
  2014年   10篇
  2013年   16篇
  2012年   29篇
  2011年   17篇
  2010年   31篇
  2009年   27篇
  2008年   20篇
  2007年   64篇
  2006年   22篇
  2005年   26篇
  2004年   23篇
  2003年   21篇
  2002年   16篇
  2001年   11篇
  2000年   17篇
  1999年   14篇
  1998年   25篇
  1997年   34篇
  1996年   26篇
  1995年   24篇
  1994年   21篇
  1993年   20篇
  1992年   13篇
  1991年   12篇
  1990年   14篇
  1989年   18篇
  1988年   23篇
  1987年   14篇
  1986年   10篇
  1985年   16篇
  1984年   7篇
  1983年   5篇
  1982年   10篇
  1981年   6篇
  1980年   9篇
  1979年   2篇
  1978年   6篇
  1977年   9篇
  1976年   7篇
  1975年   8篇
  1971年   1篇
  1970年   1篇
排序方式: 共有753条查询结果,搜索用时 15 毫秒
91.
Focal Alzheimer's disease   总被引:1,自引:0,他引:1  
Alzheimer's disease is characterized by relative sparing of primary sensory and motor cortex and a lack of sensory or motor symptomatology. We report a case of presenile onset dementia accompanied by a slowly progressive hemiparesis. Autopsy examination showed severe pathologic involvement of somatosensory cortex with neuritic plaques and neurofibrillary tangles, in addition to degeneration of the nucleus basalis and locus ceruleus. Neurochemical and immunocytochemical studies showed a moderate cortical cholinergic deficiency with normal somatostatin-like immunoreactivity and a profuse immunostaining of somatosensory cortex with the Alz-50 antibody. These unusual features emphasize that Alzheimer's disease is extremely variable in its clinical symptomatology, pathologic distribution, and neurochemical dimensions.  相似文献   
92.
93.
HIV-seropositive and seronegative control subjects performed a standard paper-and-pencil version and an experimental reaction time version of the Stroop Color-Word Naming Task. Results indicated that both symptomatic and asymptomatic HIV-positive subjects showed an exaggerated Stroop effect compared to controls, but this increase was only apparent on the RT version of the task. Analysis of components of the effect indicated that HIV-positive subjects showed increased inhibition compared to controls but normal facilitation. These results suggest that HIV-related cognitive slowing has an attentional component, most likely involving controlled processes. In addition, these results emphasize the utility and sensitivity of RT measures in the study of early HIV-1 infection.  相似文献   
94.

Background

Little research has been conducted to investigate role stress experienced by faculty members in medical schools in developing countries. This becomes even more important when the process of reform in medical education has already taken place, such as the case of Iran. The objectives of this study were to investigate and assess the level and source of role-related stress as well as dimensions of conflict among the faculty members of Iranian medical schools. Variables like the length of academic work, academic rank, employment position, and the departments of affiliation were also taken into consideration in order to determine potentially related factors.

Methods

A survey was conducted at three different ranks of public medical schools. The validated Organizational Role Stress Scale was used to investigate the level of role stress and dimensions of role conflict among medical faculty members. The response rate was 66.5%.

Results

The findings show that role stress was experienced in high level among almost all faculty members. All three studied medical schools with different ranks are threatened with relatively the same levels of role stress. Specific differences were found among faculty members from different disciplines, and academic ranks. Also having permanent position and the length of services had significant correlation with the level of role stress. The major role- related stress and forms of conflict among faculty members were role overload, role expectation conflict, inter-role distance, resource inadequacy, role stagnation, and role isolation.

Conclusion

The most role-related stressors and forms of conflict among faculty members include too many tasks and everyday work load; conflicting demands from colleagues and superiors; incompatible demands from their different personal and organizational roles; inadequate resources for appropriate performance; insufficient competency to meet the demands of their role; inadequate autonomy to make decision on different tasks; and a feeling of underutilization. The findings of this study can assist administrators and policy makers to provide an attractive working climate in order to decrease side effects and consequences of role stress and to increase productivity of faculty members. Furthermore, understanding this situation can help to develop coping strategies in order to reduce role-related stress.  相似文献   
95.
96.
Nearly 25% of patients with sickle cell disease (SCD) experience central nervous system morbidity involving both large and small vessel disease. Optimal imaging methods for determining the extent of ischemia are not known. Positron emission tomography (PET) has the unique ability to show tissue function as well as structure. Reports concerning patients with non-SCD neurodegenerative disorders suggest PET may be useful in determining prognosis. We compared magnetic resonance imaging, magnetic resonance angiography, and neuropsychological testing with PET prospectively. Six patients with SCD and a history of stroke, aged 10 to 28, were enrolled. PET studies were performed on an ECAT HR 47 scanner (Siemens/CTI, Knoxville, TN) using 18-F-fluorodeoxyglucose as a tracer. PET interpretations were conducted in blinded fashion. MRI studies found two patients with only small vessel disease and four with both large and small vessel disease. In two of four subjects with large vessel disease, PET showed a corresponding metabolic abnormality and also identified an area of hypometabolism extending beyond the anatomical lesion as shown by MRI. PET did not demonstrate an abnormality corresponding with small vessel disease. Detailed neuropsychological testing demonstrated cognitive dysfunction in all cases. For some patients, PET may add sensitivity in detecting impaired metabolism in the area surrounding a major vessel infarct. However, the technique does not appear to be generally useful in characterizing small watershed or deep white matter infarcts. Larger studies, to include control subjects and carefully selected untransfused SCD patients, are needed. A combination of conventional imaging and neuropsychological testing remains the preferred evaluation for most SCD patients with neurologic symptoms.  相似文献   
97.

Background

BEIT CURE International Hospital (BCIH) opened in 2002 providing orthopaedic surgical services to children in Malawi. This study reviews the hospital''s progress 10 years after establishment of operational services. In addition we assess the impact of the hospital''s Malawi national clubfoot programme (MNCP) and influence on orthopaedic training.

Methods

All operative paediatric procedures performed by BCIH services in the 10th operative year were included. Data on clubfoot clinic locations and number of patients treated were obtained from the MNCP. BCIH records were reviewed to identify the number of healthcare professionals who have received training at the BCIH.

Results

609 new patients were operated on in the 10th year of hospital service. Patients were treated from all regions; however 60% came from Southern regions compared with the 48% in the 5th year. Clubfoot, burn contracture and angular lower limb deformities were the three most common pathologies treated surgically. In total BCIH managed 9,842 patients surgically over a 10-year period. BCIH helped to establish and co-ordinate the MNCP since 2007. At present the program has a total of 29 clinics, which have treated 5748 patients. Furthermore, BCIH has overseen the full or partial training of 5 orthopaedic surgeons and 82 orthopaedic clinical officers in Malawi.

Conclusion

The BCIH has improved the care of paediatric patients in a country that prior to its establishment had no dedicated paediatric orthopaedic service, treating almost 10,000 patients surgically and 6,000 patients in the MNCP. This service has remained consistent over a 10-year period despite times of global austerity. Whilst the type of training placement offered at BCIH has changed in the last 10 years, the priority placed on training has remained paramount. The strategic impact of long-term training commitments are now being realised, in particular by the addition of Orthopaedic surgeons serving the nation.  相似文献   
98.
Eighteen patients with Alzheimer's disease were studied with positron emission tomographic measurements of regional cerebral metabolism of glucose. All patients were initially diagnosed and evaluated, underwent positron emission tomography, and then were followed with annual reevaluations, at which time the Mini-Mental State Examination (MMSE) was performed. Patients were followed for an average of 2.5 years, and the rate of cognitive decline was calculated by determining the rate of change in the MMSE score defined as the MMSE score at the initial evaluation minus the MMSE score at the last examination, divided by the number of months between testing. The regional cerebral metabolic rates for glucose determined at the time of the first MMSE were then regressed on these changes in scores. Results showed that glucose metabolic rates in posterior temporal and primary visual cortex regions were significantly correlated with the subsequent rate of cognitive deterioration. These associations were not confounded by age, length of follow-up, baseline MMSE score, or education. Stratification on gender suggested that these associations were much stronger in women than in men. These results replicate previous findings showing that functional brain imaging is predictive of the rate of cognitive decline in Alzheimer's disease.  相似文献   
99.
100.
Ergotamine has been used for many years in the treatment of migraine, although there is little formal clinical evidence that it is significantly more efficacious than placebo. A number of side effects associated with ergotamine have been reported in the literature, including myocardial infarction, ischaemia of limb extremities, and fibrotic changes. Long-term use has led to reported cases of ergotamine-induced headache, vascular reactivity, and subclinical ergotism. When the safety profile of this drug is considered, coupled with its debatable efficacy from a clinical review previously published, the resulting poor risk: benefit ratio brings into question the continued use of ergotamine as a migraine treatment and calls for better controlled trials of its efficacy, or lack of, in the acute treatment of migraine.  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