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   5015篇
  免费   438篇
  国内免费   9篇
耳鼻咽喉   30篇
儿科学   163篇
妇产科学   108篇
基础医学   651篇
口腔科学   67篇
临床医学   586篇
内科学   921篇
皮肤病学   54篇
神经病学   461篇
特种医学   239篇
外科学   726篇
综合类   101篇
一般理论   4篇
预防医学   594篇
眼科学   71篇
药学   361篇
中国医学   4篇
肿瘤学   321篇
  2021年   57篇
  2020年   51篇
  2019年   51篇
  2018年   65篇
  2017年   78篇
  2016年   57篇
  2015年   91篇
  2014年   136篇
  2013年   186篇
  2012年   222篇
  2011年   225篇
  2010年   172篇
  2009年   130篇
  2008年   200篇
  2007年   231篇
  2006年   199篇
  2005年   199篇
  2004年   224篇
  2003年   216篇
  2002年   225篇
  2001年   208篇
  2000年   202篇
  1999年   141篇
  1998年   46篇
  1997年   55篇
  1996年   40篇
  1995年   56篇
  1994年   42篇
  1993年   58篇
  1992年   96篇
  1991年   116篇
  1990年   115篇
  1989年   108篇
  1988年   100篇
  1987年   90篇
  1986年   90篇
  1985年   84篇
  1984年   64篇
  1983年   66篇
  1982年   41篇
  1980年   28篇
  1979年   57篇
  1978年   49篇
  1977年   30篇
  1975年   33篇
  1974年   34篇
  1973年   30篇
  1972年   35篇
  1971年   28篇
  1970年   30篇
排序方式: 共有5462条查询结果,搜索用时 31 毫秒
991.
The aim of this study was to provide an evidence‐based systematic review of the use of laparoscopic and robotic adrenalectomy in the treatment of adrenal disease as part of the International Consultation on Urological Diseases and European Association of Urology consultation on Minimally Invasive Surgery in Urology. A systematic literature search (January 2004 to January 2014) was conducted to identify comparative studies assessing the safety and efficacy of minimally invasive adrenal surgery. Subtopics including the role of minimally invasive surgery for pheochromocytoma, adrenocortical carcinoma (ACC) and large adrenal tumours were examined. Additionally, the role of transperitoneal and retroperitoneal approaches, as well as laparoendoscopic single‐site (LESS) and robotic adrenalectomy were reviewed. The major findings are presented in an evidence‐based fashion. Large retrospective and prospective data were analysed and a set of recommendations provided by the committee was produced. Laparoscopic surgery should be considered the first‐line therapy for benign adrenal masses requiring surgical resection and for patients with pheochromocytoma. While a laparoscopic approach may be feasible for selected cases of ACC without adjacent organ involvement, an open surgical approach remains the ‘gold standard’. Large adrenal tumours without preoperative or intra‐operative suspicion of ACC may be safely resected via a laparoscopic approach. Both transperitoneal and retroperitoneal approaches to laparoscopic adrenalectomy are safe. The approach should be chosen based on surgeon training and experience. LESS and robotic adrenalectomy should be considered as alternatives to laparoscopic adrenalectomy but require further study.  相似文献   
992.
993.
Objectives: The provision of nutrition care by health professionals can facilitate improved patient nutrition behaviors. Some education institutions include nutrition in their medical curriculum; however, doctors and medical students continue to lack competence in providing nutrition care. Dietitians are increasingly teaching nutrition to medical students, yet evidence on the topic remains anecdotal. It is important to understand the experiences of these dietitians to support improvements in undergraduate medical nutrition education. The aim of this study was to explore dietitians' perspectives of teaching nutrition to medical students.

Methods: A qualitative study was conducted in collaboration with the Need for Nutrition Education/Innovation Programme (NNEdPro). Twenty-four dietitians who had provided nutrition education to medical students participated in individual semistructured interviews. Participants were from Australia (n = 5), New Zealand (n = 1), the United States (n = 6), Canada (n = 5), the United Kingdom (n = 5), Germany (n = 1), and Finland (n = 1). Data analysis was conducted using a constant comparative approach to thematic analysis.

Results: The dietitians expressed confidence in their ability to teach medical students and believed that they were the most appropriate professionals to administer the education. However, they were not confident that medical students graduate with sufficient nutrition competence and attributed this to poor curriculum planning for nutrition. Dietitians had access to useful resources and tools to support education, with opportunity to contribute further to integration of nutrition throughout medical curricula.

Conclusion: This study suggests that dietitians are likely appropriate nutrition teachers in medical education. However, optimizing dietitians' role requires their further involvement in curriculum planning and development. Including dietitians as members of medical faculty would facilitate their input on nutrition throughout the curriculum, which could enhance the nutrition education of medical students.  相似文献   

994.
995.
Diamond Blackfan anaemia (DBA) is a rare, genetically and clinically heterogeneous, inherited red cell aplasia. Classical DBA affects about seven per million live births and presents during the first year of life. However, as mutated genes have been discovered in DBA, non-classical cases with less distinct phenotypes are being described in adults as well as children. In caring for these patients it is often difficult to have a clear understanding of the treatment options and their outcomes because of the lack of complete information on the natural history of the disease. The purpose of this document is to review the criteria for diagnosis, evaluate the available treatment options, including corticosteroid and transfusion therapies and stem cell transplantation, and propose a plan for optimizing patient care. Congenital anomalies, mode of inheritance, cancer predisposition, and pregnancy in DBA are also reviewed. Evidence-based conclusions will be made when possible; however, as in many rare diseases, the data are often anecdotal and the recommendations are based upon the best judgment of experienced clinicians. The recommendations regarding the diagnosis and management described in this report are the result of deliberations and discussions at an international consensus conference.  相似文献   
996.
997.
Human exposure to bisphenol A (BPA) is due to that found in the diet, and BPA and its metabolites were detected at parts per billion (or less) concentrations in human urine, milk, saliva, serum, plasma, ovarian follicular fluid, and amniotic fluid. Adverse health effects in mice and rats may be induced after parenteral injection or after massive oral doses. Controlled ingestion trials in healthy adult volunteers with 5 mg d16-BPA were unable to detect parent BPA in plasma despite exquisitely sensitive (limit of detection = 6 nM) methods, but by 96 h 100% of the administered dose was recovered in urine as the glucuronide. The extensive BPA glucuronidation following ingestion is not seen after parenteral injection; only the parent BPA binds plasma proteins and estrogen receptors (ER). The hypothesis that BPA dose-response may be described by a J- or U-shape curve was not supported by toxicogenomic data collected in fetal rat testes and epididymes (after repeated parenteral exposure at 2-400,000 microg/kg-d), where a clear monotonic dose-response both in the numbers of genes and magnitude of individual gene expression was evident. There is no clear indication from available data that the BPA doses normally consumed by humans pose an increased risk for immunologic or neurologic disease. There is no evidence that BPA poses a genotoxic or carcinogenic risk and clinical evaluations of 205 men and women with high-performance liquid chromatography (HPLC)-verified serum or urinary BPA conjugates showed (1) no objective signs, (2) no changes in reproductive hormones or clinical chemistry parameters, and (3) no alterations in the number of children or sons:daughters ratio. Results of benchmark dose (BMD10 and BMDL10) calculations and no-observed-adverse-effect level (NOAEL) inspections of all available and reproducible rodent studies with oral BPA found BMD and NOAEL values all greater than the 5 mg/kg-d NOAELs from mouse and rat multigeneration reproduction toxicity studies. While allometric and physiologically based pharmacokinetic (PBPK) models were constructed for interspecies scaling of BPA and its interaction with ER, multigeneration feeding studies with BPA at doses spanning 5 orders of magnitude failed to identify signs of developmental toxicity or adverse changes in reproductive tract tissues; the 5-mg/kg-d NOAELs identified for systemic toxicity in rats and mice were less than the oral NOAELs for reproductive toxicity. Thus, it is the generalized systemic toxicity of ingested BPA rather than reproductive, immunologic, neurobehavioral, or genotoxic hazard that represents the point of departure. Using U.S. Environmental Protection Agency (EPA) uncertainty factor guidance and application of a threefold database uncertainty factor (to account for the fact that the carcinogenic potential of transplacental BPA exposure has yet to be fully defined and comprehensive neurobehavioral and immunotoxicologic evaluations of BPA by relevant routes and at relevant doses have yet to be completed) to the administered dose NOAEL results in an oral RfD of 0.016 mg/kg-d. Assuming the 70-kg adult consumes 2 L of water each day and adopting the default 20% U.S. EPA drinking water relative source contribution yields a 100 microg/L BPA total allowable concentration (TAC).  相似文献   
998.
999.
The present study is a non-inferiority comparison of duloxetine 60-120 mg/day and venlafaxine extended-release (XR) 75-225 mg/day for the treatment of adults with generalized anxiety disorder (GAD). The non-inferiority test was a prespecified plan to pool data from two nearly identical 10-week, multicentre, randomized, placebo-controlled, double-blind studies of duloxetine 60-120 mg/day and venlafaxine 75-225 mg/ day for the treatment of GAD. An independent expert consensus panel provided six statistical and clinical criteria for determining non-inferiority between treatments. Response was defined as > or =50% reduction in Hamilton Anxiety Rating Scale (HAMA) total score. In the pooled sample, patients were randomly assigned to duloxetine (n = 320), venlafaxine XR (n = 333) or placebo (n = 331). For the non-inferiority analysis, the per-protocol patients who were treated with duloxetine (n = 239) or venlafaxine XR (n = 262) improved significantly more (mean HAMA reductions were -15.4 and -15.2, respectively) than placebo-treated patients (n = 267; -11.6, P < or = 0.001, both comparisons). Response rates were 56%, 58% and 40%, respectively. Discontinuation rate because of AEs was significantly higher for duloxetine (13.4%, P < or = 0.001) and venlafaxine XR (11.4%, P < or = 0.01) groups compared with placebo (5.4%). Duloxetine 60-120 mg/day met all statistical and clinical criteria for non-inferiority and exhibited a similar tolerability profile compared with venlafaxine XR 75-225 mg/day for the treatment of adults with GAD.  相似文献   
1000.
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