首页 | 官方网站   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   5094篇
  免费   347篇
  国内免费   11篇
医药卫生   5452篇
  2021年   45篇
  2020年   46篇
  2019年   57篇
  2018年   87篇
  2017年   44篇
  2016年   77篇
  2015年   89篇
  2014年   124篇
  2013年   172篇
  2012年   235篇
  2011年   229篇
  2010年   132篇
  2009年   155篇
  2008年   232篇
  2007年   247篇
  2006年   240篇
  2005年   223篇
  2004年   200篇
  2003年   232篇
  2002年   213篇
  2001年   175篇
  2000年   202篇
  1999年   169篇
  1998年   76篇
  1997年   46篇
  1996年   33篇
  1995年   35篇
  1994年   36篇
  1992年   94篇
  1991年   91篇
  1990年   93篇
  1989年   93篇
  1988年   84篇
  1987年   69篇
  1986年   75篇
  1985年   68篇
  1984年   49篇
  1983年   54篇
  1982年   30篇
  1980年   33篇
  1979年   63篇
  1978年   43篇
  1977年   36篇
  1975年   37篇
  1974年   40篇
  1973年   59篇
  1972年   51篇
  1971年   36篇
  1970年   38篇
  1969年   37篇
排序方式: 共有5452条查询结果,搜索用时 31 毫秒
1.
We have investigated the prognostic value of two novel interim 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) parameters in patients undergoing chemoradiation (CRT) for esophageal squamous cell carcinoma (ESCC): one tumor parameter (maximal standardized uptake ratio rSUR) and one normal tissue parameter (change of FDG uptake within irradiated nontumor-affected esophagus SUVNTO). PET data of 134 European and Chinese patients were analyzed. Parameter establishment was based on 36 patients undergoing preoperative CRT plus surgery, validation was performed in 98 patients receiving definitive CRT. Patients received PET imaging prior and during fourth week of CRT. Clinical parameters, baseline PET parameters, and interim PET parameters (rSUR and SUVNTO) were analyzed and compared to event-free survival (EFS), overall survival (OS), loco-regional control (LRC) and freedom from distant metastases (FFDM). Combining rSUR and SUVNTO revealed a strong prognostic impact on EFS, OS, LRC and FFDM in patients undergoing preoperative CRT. In the definitive CRT cohort, univariate analysis with respect to EFS revealed several staging plus both previously established interim PET parameters as significant prognostic factors. Multivariate analyses revealed only rSUR and SUVNTO as independent prognostic factors (p = 0.003, p = 0.008). Combination of these parameters with the cutoff established in preoperative CRT revealed excellent discrimination of patients with a long or short EFS (73% vs. 17% at 2 years, respectively) and significantly discriminated all other endpoints (OS, p < 0.001; LRC, p < 0.001; FFDM, p = 0.02), even in subgroups. Combined use of interim FDG-PET derived parameters SUVNTO and rSUR seems to have predictive potential, allowing to select responders for definitive CRT and omission of surgery.  相似文献   
2.
Abstract

Aim: To analyze the effects of body weight loss on bone mineral density (BMD) on hip (Hip BMD) and lumbar spine (Lumbar BMD) after six months of bariatric surgery. Bariatric surgery is an effective treatment for morbid obesity. Nonetheless, there are scant data on the effect of weight bearing on bone structure.

Material and methods: Seventeen obese women aged 41.2?±?11.3 yrs. who underwent Roux-en-Y gastric bypass (RYGB) were included. Body composition assessments were performed through dual-energy X-ray absorptiometry immediately before and after 6-months RYGB. Data collected pre- and post-RYGB included total body weight, body mass index (BMI), lean body mass (LM), fat mass (FM) and bone mineral content. The pre- (PRE) and post-operative (POST) results were compared.

Results: Lumbar BMD POST presented a non-significant loss of 1.8% whereas Hip BMD POST showed a significant loss of 17.8%. The analysis demonstrated that BMI and LM PRE explained 26% and 49%, respectively, of Hip BMD PRE variability. In addition, LM POST explained 30% of hip BMD POST variability and was not significant for Lumbar BMD POST.

Conclusions: Obesity and rapid weight loss showed direct influence in Hip BMD after six months of bariatric surgery. However, its effect on the lumbar spine area was smaller due to the higher capacity of the spine to dissipate loads through its curvature.  相似文献   
3.
4.
5.
Past studies have shown that various aspects of occupational attainment (unemployment, job instability, low occupational status, and low earnings) are associated with poor mental health, but each of these studies focused on one or two aspects of occupational attainment. Consequently, it remains unclear whether their associations are independent of each other. Further, little is known about whether negative self‐assessments of occupational attainment are linked to poor mental health. We sought to overcome these limitations of past research while focusing on depressive symptoms as a mental health outcome and young adulthood as a life stage context. The study analysed U.S. data from the National Longitudinal Study of Adolescent to Adult Health (n = 13,178) using ordinary least square models. The analysis showed that all aspects of occupational attainment were associated with depressive symptoms in the expected directions. Further, unemployment, job instability, and negative self‐assessment of career progress showed stronger associations, and those associations were independent of other occupational attainment variables. Overall, the results suggested that understanding the association between occupational attainment and mental health requires close attention to the life stage context.  相似文献   
6.
7.
Background: At present, there are no meaningful and sophisticated computer games that simultaneously allow the treatment of movement disorders such as Parkinson's syndrome. In particular, there are no systems to consider the severity of the disease and the physical skills of the patient.

Methods: A computer game using the Microsoft Kinect as markerless sensor for the 3?D recognition of the patient’s movement was developed to support the rehabilitation. The scenario of a basketball game was created after determining that the movement like throwing a ball and the correct posture of the body are important. A study based on system usability was performed with 15 patients to evaluate the system.

Results: The technical feasibility of a computer-assisted training system for supporting patients with Parkinson‘s disease has been demonstrated. No markers on the patient are required for movement detection and allow a user-friendly handling. Regarding the usability study, the patients were accepting of such a system and its at-home use and symptoms like ‘freezing’ and the Pisa syndrome can be treated.

Conclusions: The physiotherapist can be assisted by the developed rehabilitation system. An objective measurement of the patient’s training progress delivers valuable information to adjust the training sessions for every patient individually. Due to its modular character, the system can also be applied to other diseases or sports injuries and offers the basis for further development.  相似文献   

8.
9.
Krause  P.  Völzmann  S.  Ewert  S.  Kupsch  A.  Schneider  G. H.  Kühn  Andrea A. 《Journal of neurology》2020,267(6):1622-1631
Journal of Neurology - Observational study to evaluate the long-term motor and non-motor effects of deep brain stimulation (DBS) of the globus pallidus internus (GPi) on medically refractory...  相似文献   
10.
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-23

京公网安备 11010802026262号