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   223187篇
  免费   20284篇
  国内免费   4677篇
耳鼻咽喉   3338篇
儿科学   4074篇
妇产科学   3609篇
基础医学   16984篇
口腔科学   7583篇
临床医学   22046篇
内科学   23707篇
皮肤病学   2444篇
神经病学   11598篇
特种医学   5993篇
外国民族医学   17篇
外科学   21473篇
综合类   35257篇
现状与发展   9篇
一般理论   24篇
预防医学   30405篇
眼科学   2054篇
药学   21273篇
  362篇
中国医学   26170篇
肿瘤学   9728篇
  2024年   989篇
  2023年   4470篇
  2022年   8438篇
  2021年   11072篇
  2020年   10819篇
  2019年   11905篇
  2018年   10682篇
  2017年   9372篇
  2016年   8479篇
  2015年   7835篇
  2014年   15222篇
  2013年   15726篇
  2012年   13574篇
  2011年   14423篇
  2010年   11618篇
  2009年   10082篇
  2008年   9368篇
  2007年   9334篇
  2006年   7951篇
  2005年   6778篇
  2004年   5619篇
  2003年   4965篇
  2002年   3887篇
  2001年   3226篇
  2000年   2818篇
  1999年   2300篇
  1998年   1886篇
  1997年   1697篇
  1996年   1365篇
  1995年   1296篇
  1994年   1190篇
  1993年   1059篇
  1992年   971篇
  1991年   877篇
  1990年   751篇
  1989年   723篇
  1988年   681篇
  1987年   609篇
  1986年   545篇
  1985年   1799篇
  1984年   2063篇
  1983年   1294篇
  1982年   1711篇
  1981年   1183篇
  1980年   1013篇
  1979年   906篇
  1978年   739篇
  1977年   554篇
  1976年   696篇
  1975年   479篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
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   
82.
83.

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   
84.

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   
85.
《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   
86.
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   
87.
ObjectiveThe main objective of this study is to define the factors associated with frailty and psychosocial imbalance in elderly people who live in the community.MethodsMulticentre prospective study with a representative sample of subjects older than 75 years who live in the community in the province of Huesca (Spain). 5-year follow-up with biannual assessment. Standardised individual assessment carried out by GPs trained to assess depression, anxiety, cognitive impairment, psychotic symptoms, sarcopenia, social network, dependence for basic and instrumental activities of daily living, physical severity, risk of dependence and quality of life. Further assessment two and five years later to quantify adverse events: institutionalisation, functional impairment or mortality. Possible risk factors will be assessed: gender, age, social status, functional status, mental status and physical severity. Predictive and individual risk models will be designed in order to identify elderly people with high psychosocial frailty and destabilisation risk.ConclusionsAn understanding of the possible risk factors would facilitate the identification of elderly subjects at greater risk of psychosocial frailty, thereby enabling preventive activities to be implemented aimed at reducing frailty and associated adverse events (institutionalisation, mortality, etc.).  相似文献   
88.
89.
90.
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