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   4852篇
  免费   336篇
  国内免费   9篇
医药卫生   5197篇
  2021年   43篇
  2020年   45篇
  2019年   53篇
  2018年   83篇
  2017年   40篇
  2016年   75篇
  2015年   86篇
  2014年   117篇
  2013年   160篇
  2012年   216篇
  2011年   214篇
  2010年   122篇
  2009年   140篇
  2008年   215篇
  2007年   228篇
  2006年   223篇
  2005年   210篇
  2004年   191篇
  2003年   210篇
  2002年   199篇
  2001年   175篇
  2000年   200篇
  1999年   163篇
  1998年   72篇
  1997年   44篇
  1996年   31篇
  1995年   33篇
  1994年   32篇
  1992年   94篇
  1991年   87篇
  1990年   90篇
  1989年   93篇
  1988年   84篇
  1987年   69篇
  1986年   73篇
  1985年   68篇
  1984年   47篇
  1983年   53篇
  1982年   29篇
  1980年   31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5197条查询结果,搜索用时 15 毫秒
1.
Der Freie Zahnarzt -  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.
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   
5.
6.
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   
7.
8.
9.
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   
10.

Background

Following the Nepal earthquake in April 2015, UNFPA estimated that 1.4 million women of reproductive age were affected, with approximately 93,000 pregnant and 28,000 at risk of sexual violence. A set of priority reproductive health (RH) actions, the Minimum Initial Services Package (MISP), was initiated by government, international and local actors. The purpose of this study was to identify the facilitators and barriers affecting the implementation of priority RH services in two districts.

Methods

In September 2015, a mixed methods study design was used in Kathmandu and Sindhupalchowk districts to assess the implementation of the priority RH services five months post-earthquake. Data collection activities included 32 focus group discussions with male and female participants aged 18–49; 26 key informant interviews with RH, gender-based violence (GBV), and human immunodeficiency virus (HIV) experts; and 17 health facility assessments.

Results

The implementation of priority RH services was achieved in both districts. In Kathmandu implementation of emergency RH services started within days of the earthquake. Facilitating factors for successful implementation included disaster preparedness; leadership and commitment among national, international, and district level actors; resource mobilization; strong national level coordination; existing reproductive and child health services and community outreach programs; and supply chain management. Barriers included inadequate MISP training for RH coordinators and managers; weak communication between national and district level stakeholders; inadequate staffing; under-resourced and fewer facilities in rural areas; limited attention given to local GBV and HIV organizations; low availability of clinical management of rape services; and low awareness of GBV services and benefits of timely care.

Conclusion

Ensuring RH is included in emergency preparedness and immediate response efforts and is continued through the transition to comprehensive care is critical for national governments and humanitarian response agencies. The MISP for RH remains a critical component of response efforts, and the humanitarian community should consider these learnings in future emergency response.
  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-23

京公网安备 11010802026262号