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   223891篇
  免费   19735篇
  国内免费   4772篇
耳鼻咽喉   3343篇
儿科学   4326篇
妇产科学   3623篇
基础医学   19221篇
口腔科学   7299篇
临床医学   20059篇
内科学   21658篇
皮肤病学   2453篇
神经病学   15601篇
特种医学   5868篇
外国民族医学   12篇
外科学   21583篇
综合类   34365篇
现状与发展   11篇
一般理论   25篇
预防医学   29352篇
眼科学   2296篇
药学   21397篇
  337篇
中国医学   26309篇
肿瘤学   9260篇
  2024年   960篇
  2023年   4444篇
  2022年   8316篇
  2021年   10942篇
  2020年   10576篇
  2019年   12187篇
  2018年   10940篇
  2017年   9203篇
  2016年   8129篇
  2015年   7593篇
  2014年   14917篇
  2013年   15518篇
  2012年   13353篇
  2011年   14445篇
  2010年   11641篇
  2009年   10141篇
  2008年   9514篇
  2007年   9538篇
  2006年   8157篇
  2005年   6883篇
  2004年   5733篇
  2003年   5084篇
  2002年   3939篇
  2001年   3301篇
  2000年   2870篇
  1999年   2375篇
  1998年   1911篇
  1997年   1716篇
  1996年   1409篇
  1995年   1362篇
  1994年   1196篇
  1993年   1058篇
  1992年   976篇
  1991年   883篇
  1990年   759篇
  1989年   723篇
  1988年   678篇
  1987年   594篇
  1986年   556篇
  1985年   1861篇
  1984年   2113篇
  1983年   1339篇
  1982年   1751篇
  1981年   1212篇
  1980年   1035篇
  1979年   918篇
  1978年   752篇
  1977年   570篇
  1976年   707篇
  1975年   486篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
Core executive functions (EF) such as attention, and working memory have been strongly associated with academic achievement, language development and behavioral stability. In the case of children who are vulnerable to cognitive and learning problems because of an underlying intellectual disability, EF difficulties will likely exacerbate an already compromised cognitive system. The current review examines cognitive training programs that aim to improve EF, specifically focusing on the potential of this type of intervention for children who have intellectual disabilities. We conclude that despite considerable discrepancies regarding reported intervention effects, these inconsistencies can be attributed to flaws in both program and study design. We discuss the steps needed to address these limitations and to facilitate the advancement of non-pharmaceutical interventions for children with intellectual disabilities.  相似文献   
83.
This paper describes and analyzes a proposed solution of fundamental limitative factor of teleradiology to overcome the teleradiology usages problems in underdeveloped and developing countries. The goal is to achieve a very simple and cost-efficient way to take advantage of teleradiology in anywhere even in remote and rural areas. To meet the goal of this study, the following methodology which is consists of two main procedures was done: (1) Using a digital camera in order to provide a digital image from radiographs. (2) Using an image compression tool in order to compress digital images. The results showed that there is no significant difference between digital images (non-compress and compress images) and radiographic films. Also, there was a logic relationship between the diagnostic quality and diagnostic accuracy. Since the maximum percent of diagnostic accuracy can be seen among “Good” quality images and the minimum to was related “Poor”. The results of our study indicate that a digital camera could be utilized to capture digital images from radiographic films of chest x-ray. To reduce the size of digital images, a lossy compression technique could be applied at compression percent of 50 or less without any significant differences. The compressed images can be sent easily by email to other places for consultation and also they can be stored with a smaller size.  相似文献   
84.
85.

Background

Laparoscopic Roux-en-Y gastric bypass, laparoscopic sleeve gastrectomy, and laparoscopic adjustable gastric banding all lead to substantial weight loss in obese patients. Long-term weight loss can be highly variable beyond 1-year postsurgery. This study examines and compares the frequency distribution of weight loss and lack of treatment effect rates after laparoscopic Roux-en-Y gastric bypass, laparoscopic sleeve gastrectomy, and laparoscopic adjustable gastric banding.

Methods

A total of 1,331 consecutive patients at a single academic institution were reviewed from a prospectively collected database. Preoperative data collected included demographics, body mass index, and percent excess weight loss. Postoperative BMI and %EWL were collected at 12, 24, and 36 months. Percent excess weight loss was analyzed by the percentiles of excess weight lost, and the distribution of percent excess weight loss was evaluated in 10% increments. Lack of a successful treatment effect was defined as <25% excess weight loss.

Results

Of the 1,331 patients, 72.4% (963) underwent laparoscopic Roux-en-Y gastric bypass, 18.3% (243) laparoscopic sleeve gastrectomy, and 9.4%(125) laparoscopic adjustable gastric banding. Mean percent excess weight loss was greatest for laparoscopic Roux-en-Y gastric bypass, followed by laparoscopic sleeve gastrectomy, and then by laparoscopic adjustable gastric banding at every time point: at 2 years mean percent excess weight loss was 77.9± 24.4 for laparoscopic Roux-en-Y gastric bypass, 50.8 ± 25.8 for laparoscopic sleeve gastrectomy, and 40.8± 25.9 for laparoscopic adjustable gastric banding (P < .0001). The rates of a successful treatment effect s for laparoscopic Roux-en-Y gastric bypass, laparoscopic sleeve gastrectomy, and laparoscopic adjustable gastric banding were 0.9%, 5.2%, and 24.3% at 1 year; 0.3%, 11.1%, and 26.0% at 2 years; and 1.0%, 25.3%, and 30.2% at 3 years. At 1 year, the odds ratio of lack of a successful treatment effect of laparoscopic sleeve gastrectomy versus laparoscopic Roux-en-Y gastric bypass was 6.305 (2.125–19.08; P?=?.0004), the odds ratio for laparoscopic adjustable gastric banding versus laparoscopic Roux-en-Y gastric bypass was 36.552 (15.64–95.71; P < .0001), and the odds ratio for laparoscopic adjustable gastric banding versus laparoscopic sleeve gastrectomy was 5.791 (2.519–14.599; P < .0001). At 2 years, the odds ratio for laparoscopic sleeve gastrectomy versus laparoscopic Roux-en-Y gastric bypass increased to 70.7 (9.4–531.7; P < .0001), the odds ratio for laparoscopic adjustable gastric banding versus laparoscopic Roux-en-Y gastric bypass increased to 128.1 (16.8–974.3; P < .0001), and the odds ratio for laparoscopic adjustable gastric banding versus laparoscopic sleeve gastrectomy decreased to 1.8 (0.9–3.6; P?=?.09).

Conclusion

This study emphasizes the existing variability in weight loss across bariatric procedures as well as in the lack of a treatment effect for each procedure. Although laparoscopic adjustable gastric banding has the greatest rate of a lack of a successful treatment effect, the rate remained stable over 3 years postoperatively. Laparoscopic sleeve gastrectomy showed a doubling in the rate of a lack of a successful treatment effect every year reaching 25% at year 3. The rates for lack of a successful treatment effect for laparoscopic Roux-en-Y gastric bypass remained stable at about 1% for the first 3 years postoperatively.  相似文献   
86.

Background

Arterial vascular anomalies in patients undergoing kidney transplantation (KT) are correlated with a higher incidence of early surgical complications, potentially causing graft loss. Arterial reconstruction allows patients to overcome these surgical challenges, thus minimizing the risk of poor outcomes. The aim of the present study is to retrospectively investigate the safety and effectiveness of the multiple arterial reconstruction technique with a Teflon patch in case of an unavailable aortic patch: to do so, surgical complications, graft function, and patient survival were evaluated.

Methods

During the period January 2009 to August 2016, 202 adult deceased-donor KTs were performed at our center. Group A (n = 27; reconstruction of multiple arteries) and Group B (n = 175; control group) were compared.

Results

No differences were observed between the 2 groups in terms of early postoperative course, with no vascular complication observed in Group A. No vascular patch infections were reported, nor longer cold ischemia time rates. Similarly, long-term survival rates were similar between the 2 groups.

Conclusions

The Teflon-patch arterial reconstruction technique appears to be safe and effective, with an acceptable balance of benefits and potential risks of using a prosthetic material. Studies based on larger series are needed to further validate this approach.  相似文献   
87.
《The surgeon》2022,20(1):16-40
Surgical Innovations are central to surgical progress, and have led to exponential growth in various fields of Surgery. Surgical Innovations in Lower and Middle Income Countries are the result of creativity of frontline health workers in search of simple, safe and ethical solutions for their unique challenges. The key lies in: ‘simplifying the idea/technique/device’ to find patients' needs-driven low-cost innovative surgical solutions; which can be used on a wider scale to achieve health equity for underserved populations. Local surgeons understand the difficulties and nuances of various problems and can provide local-evidence-based customized solutions for their patients' health problems. We developed a Surgical Innovation Ecosystem allowing us to see difficulties as opportunities, learn from everyone and conduct research on what is ‘important’ rather than what is ‘interesting’. Barriers to Surgical Innovations in Lower and Middle Income Countries are well known; however, a roadmap to overcome these barriers is now available. The right balance has to be found between encouraging creativity and innovation while maintaining ethical awareness and responsibility to patients. Introduction and adoption of Surgical Innovations are governed by evidence-based principles and have to undergo a rigorous and scientific evaluation. Science of Surgical Innovations has finally come of age and is getting its due recognition and the pioneering innovators are receiving the much needed appreciation and support.  相似文献   
88.
ObjectiveTo estimate the prospective relationships between exposure to psychosocial risks dimensions included in the COPSOQ-Istas21 and the deterioration of general and mental health and sleep problems among workers residing in Spain.MethodCohort whose baseline corresponds to the 2016 Psychosocial Risks Survey with a new measurement after one year.ResultsSocial capital and interpersonal relations and leadership dimensions, as well as work?life conflict, were related to all health variables. Dimensions of work organization and job contents did it especially with the mental health, the quantitative demands with the general health and the emotional ones with the mental health. The dimensions related to job insecurity did not show relationships with health.ConclusionsThe results obtained reinforce the role of the COPSOQ-Istas21 as a useful instrument for the evaluation and prevention of psychosocial risks at work.  相似文献   
89.
90.
Effective communication between clinicians, patients, and families at end of life is associated with better clinical outcomes. A large body of literature describes the key skills needed for effective communication. We believe that clinicians could also benefit from communication skills more commonly associated with business or law negotiations. We will demonstrate via analogy (i.e. buying a house) how four key business/law negotiation techniques – 1. Determine your Reservation and Aspiration Value; 2. Separate People from their Positions; 3. Separate Positions from Interests; and 4. Logrolling of Interests – can be applied to a difficult family meeting in a home hospice patient.  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