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   1067篇
  免费   82篇
  国内免费   1篇
耳鼻咽喉   6篇
儿科学   21篇
妇产科学   15篇
基础医学   150篇
口腔科学   9篇
临床医学   115篇
内科学   210篇
皮肤病学   20篇
神经病学   67篇
特种医学   198篇
外科学   127篇
综合类   5篇
预防医学   59篇
眼科学   31篇
药学   80篇
中国医学   1篇
肿瘤学   36篇
  2023年   7篇
  2022年   11篇
  2021年   16篇
  2020年   14篇
  2019年   19篇
  2018年   22篇
  2017年   30篇
  2016年   33篇
  2015年   29篇
  2014年   32篇
  2013年   33篇
  2012年   42篇
  2011年   44篇
  2010年   38篇
  2009年   34篇
  2008年   53篇
  2007年   49篇
  2006年   38篇
  2005年   40篇
  2004年   40篇
  2003年   56篇
  2002年   42篇
  2001年   37篇
  2000年   37篇
  1999年   53篇
  1998年   9篇
  1997年   20篇
  1996年   18篇
  1995年   9篇
  1994年   6篇
  1993年   12篇
  1992年   26篇
  1991年   20篇
  1990年   20篇
  1989年   16篇
  1988年   10篇
  1987年   16篇
  1986年   17篇
  1985年   13篇
  1984年   12篇
  1983年   5篇
  1979年   5篇
  1978年   9篇
  1977年   5篇
  1975年   5篇
  1974年   6篇
  1973年   8篇
  1972年   4篇
  1970年   4篇
  1967年   4篇
排序方式: 共有1150条查询结果,搜索用时 15 毫秒
101.
Each experiential session is to achieve two goals. One is to enable the person to undergo a qualitative shift into being the transformed new person that the person can become. A second goal is for the qualitatively new person to be essentially free of the painful feeling and scene that were front and center for the person in the session. Each session proceeds through a sequence of steps, and each step is achieved by its own collection of working methods.  相似文献   
102.
103.
OBJECTIVE: To study the course of attention-deficit/hyperactivity disorder (ADHD) in late childhood to adolescence using a multi-informant and multi-assessment procedure. METHOD: Subjects were 35 children with ADHD and 35 matched controls with a mean age of 10 years at first assessment. DSM-III-R-based structured diagnostic interviews and behavioral questionnaires based on parents, teachers, and youth informants were used. Cross-informant behavioral syndromes were obtained by use of the Child Behavior Checklist, the Teacher's Report Form, and the Youth Self-Report. Subjects were reassessed after 1.5 and 2.6 years. RESULTS: Behavioral differences between the two groups were significant for the majority of scales for all three informants at all three times. Diagnostic interviews revealed a persistence rate of 46% over 2.6 years. However, there were only few significant behavioral differences across informants between the nonpersistent and the persistent groups. The fit between interview-derived syndrome scores reflecting subtypes of ADHD and both parents and youth questionnaire data was good, whereas for the teacher ratings it was poor. A high rate of 89% correct classification of the outcome diagnoses was possible based on behavioral data at time 1. CONCLUSIONS: The study of the course of ADHD should be based both on interview and questionnaire data and should include several informants. Operationally defined diagnoses alone may lead to an underestimation of persistent behavioral problems.  相似文献   
104.
OBJECTIVE: To investigate differences in lesions and surrounding normal appearing white matter (NAWM) by perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI) in patients with acute and chronic ischemic stroke and multiple sclerosis (MS). METHODS: Study subjects included 45 MS patients, 22 patients with acute ischemic stroke and 20 patients with chronic ischemic stroke. All subjects underwent T2-weighted imaging (WI), flair attenuated inversion recovery (FLAIR), DWI and dynamic contrast enhanced PWI. Apparent diffusion coefficient (ADC) and mean transit time (MTT) maps were generated and values were calculated in the acute and chronic ischemic and demyelinating lesions, and in NAWM for distances of 5, 10 and 15 mm. Fifty-three acute ischemic and 33 acute demyelinating lesions, and 775 chronic ischemic and 998 chronic demyelinating lesions, were examined. Univariate, multivariate and data mining analyses were used to examine the feasibility of a prediction model between different lesion types. Correctly and incorrectly classified lesions, true positive (TP), false positive (FP) and precision rates were calculated. RESULTS: Patients with acute ischemic lesions presented more prolonged mean MTT values in lesions (p=0.002) and surrounding NAWM for distances of 5, 10 and 15 mm (all p<0.0001) than those with acute demyelinating lesions. In multinomial logistic regression analysis, 65 of 86 acute lesions were correctly classified (75.6%). The TP rates were 81.1% for acute ischemic lesions and 66.7% for acute demyelinating lesions. The FP rates were 33.3% for acute ischemic and 18.9% for acute demyelinating lesions. The precision was 79.6% for classification of acute ischemic lesions and 68.8% for prediction of acute demyelinating lesions. The logistic model tree decision algorithm revealed that prolonged MTT of surrounding NAWM for a distance of 15 mm (> or =7459.2 ms) was the best classifier of acute ischemic versus acute demyelinating lesions. Patients with chronic ischemic lesions presented higher mean ADC (p<0.0001) and prolonged MTT (p=0.013) in lesions, and in surrounding NAWM for distances of 5, 10 and 15 mm (all p<0.0001), compared to the patients with chronic demyelinating lesions. Data mining analyses did not show reliable predictability for correctly discerning between chronic ischemic and chronic demyelinating lesions. The precision was 56.7% for classification of chronic ischemic and 58.9% for prediction of chronic demyelinating lesions. DISCUSSION: We found prolonged MTT values in lesions and surrounding NAWM of patients with acute and chronic ischemic stroke when compared to MS patients. The use of PWI is a promising tool for differential diagnosis between acute ischemic and acute demyelinating lesions. The results of this study contribute to a better understanding of the extent of hemodynamic abnormalities in lesions and surrounding NAWM in patients with MS.  相似文献   
105.
Schultergelenkinstabilität   总被引:1,自引:0,他引:1  
Sailer J  Imhof H 《Der Radiologe》2004,44(6):578-590
Shoulder instability is a common clinical feature leading to recurrent pain and limited range of motion within the glenohumeral joint. Instability can be due a single traumatic event, general joint laxity or repeated episodes of microtrauma. Differentiation between traumatic and atraumatic forms of shoulder instability requires careful history and a systemic clinical examination. Shoulder laxity has to be differentiated from true instability followed by the clinical assessment of direction and degree of glenohumeral translation.Conventional radiography and CT are used for the diagnosis of bony lesions. MR imaging and MR arthrography help in the detection of soft tissue affection, especially of the glenoid labrum and the capsuloligamentous complex.The most common lesion involving the labrum is the anterior labral tear, associated with capsuloperiostal stripping (Bankart lesion). A number of variants of the Bankart lesion have been described, such as ALPSA, SLAP or HAGL lesions.The purpose of this review is to highlight different forms of shoulder instability and its associated radiological findings with a focus on MR imaging.  相似文献   
106.
107.

Purpose

Our purpose in this study was to assess the added clinical value of hybrid 18F–FDG-PET/MRI compared to conventional imaging for locoregional staging in breast cancer patients undergoing neoadjuvant chemotherapy (NAC).

Methods

In this prospective study, primary invasive cT2-4 N0 or cT1-4 N+ breast cancer patients undergoing NAC were included. A PET/MRI breast protocol was performed before treatment. MR images were evaluated by a breast radiologist, blinded for PET images. PET images were evaluated by a nuclear physician. Afterwards, a combined PET/MRI report was written. PET/MRI staging was compared to conventional imaging, i.e., mammography, ultrasound and MRI. The proportion of patients with a modified treatment plan based on PET/MRI findings was analyzed.

Results

A total of 40 patients was included. PET/MRI was of added clinical value in 20.0% (8/40) of patients, changing the treatment plan in 10% and confirming the malignancy of suspicious lesions on MRI in another 10%. In seven (17.5%) patients radiotherapy fields were extended because of additional or affirmative PET/MRI findings being lymph node metastases (n = 5) and sternal bone metastases (n = 2). In one (2.5%) patient radiotherapy fields were reduced because of fewer lymph node metastases on PET/MRI compared to conventional imaging. Interestingly, all treatment changes were based on differences in number of lymph nodes suspicious for metastasis or number of distant metastasis, whereas differences in intramammary tumor extent were not observed.

Conclusion

Prior to NAC, PET/MRI shows promising results for locoregional staging compared to conventional imaging, changing the treatment plan in 10% of patients and potentially replacing PET/CT or tissue sampling in another 10% of patients.
  相似文献   
108.
109.

Background  

The extent of disease burden of musculoskeletal conditions (MSC) not due to injury has not been well determined in sub-Saharan Africa. The 1999 Global Burden of Disease study estimated the prevalence of osteoarthritis and rheumatoid arthritis to be 150/100,000 compared to 1,500/100,000 in Europe. The objective of the study was to determine the prevalence of MSC and the functional implications in a sample of people attending community health centres in Cape Town, South Africa.  相似文献   
110.
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