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   1539282篇
  免费   122936篇
  国内免费   3740篇
耳鼻咽喉   20197篇
儿科学   50596篇
妇产科学   43822篇
基础医学   217814篇
口腔科学   43871篇
临床医学   135819篇
内科学   313532篇
皮肤病学   36468篇
神经病学   127779篇
特种医学   57895篇
外国民族医学   484篇
外科学   226441篇
综合类   33897篇
现状与发展   4篇
一般理论   538篇
预防医学   124260篇
眼科学   34074篇
药学   106431篇
  1篇
中国医学   3892篇
肿瘤学   88143篇
  2021年   13942篇
  2019年   14463篇
  2018年   20406篇
  2017年   15517篇
  2016年   16882篇
  2015年   19139篇
  2014年   26838篇
  2013年   38823篇
  2012年   53848篇
  2011年   56773篇
  2010年   32654篇
  2009年   31031篇
  2008年   51145篇
  2007年   54060篇
  2006年   54018篇
  2005年   52877篇
  2004年   50353篇
  2003年   47749篇
  2002年   44583篇
  2001年   76058篇
  2000年   77577篇
  1999年   64318篇
  1998年   18103篇
  1997年   16358篇
  1996年   16488篇
  1995年   15556篇
  1994年   14164篇
  1993年   13286篇
  1992年   47557篇
  1991年   45125篇
  1990年   43026篇
  1989年   41055篇
  1988年   37608篇
  1987年   36711篇
  1986年   34156篇
  1985年   32499篇
  1984年   24721篇
  1983年   20760篇
  1982年   12613篇
  1981年   11179篇
  1979年   21365篇
  1978年   15030篇
  1977年   12453篇
  1976年   11673篇
  1975年   12031篇
  1974年   14439篇
  1973年   13972篇
  1972年   13005篇
  1971年   11796篇
  1970年   11284篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Interest in inguinal hernia surgery has increased significantly with the introduction of new operating techniques during the past decade. This multicenter study compared short-term results in patients treated by the laparoscopic transabdominal preperitoneal patch technique (TAPP; n=518) and the Shouldice technique (n=524). We evaluated demographics, operative data, complications, hospital stay, postoperative pain, use of analgesics, functional status, sick leave, and complaints up to 3 months postoperatively. The median operating time was shorter in the Shouldice group (55 vs. 65 min), but there were no significant differences in complication rates, and major complications were rare. The hospital stay was 1 day or less in over 98% of cases in both groups, but more operations were performed on outpatient basis in the Shouldice group. In the TAPP group postoperative pain and analgesic consumption were less, postoperative functional status was better, and sick leave was shorter (10 vs. 14 days). These results show that the two methods are equally safe and have few major complications. The TAPP operation is associated with less postoperative pain, better postoperative functional status, and shorter sick leave, but at the price of a longer operating time. Electronic Publication  相似文献   
992.
Cough and paradoxical vocal fold motion   总被引:8,自引:0,他引:8  
OBJECTIVES: The differential diagnosis and treatment of patients with chronic cough, paradoxical vocal fold motion, and disordered breathing can be a challenge to most practicing otolaryngologists. Tracheobronchial (ie, asthma, bronchitis, and tracheal stenosis), laryngeal (ie, vocal fold paralysis and neoplasms), and rhinologic (ie, allergies and rhinosinusitis) etiologies are commonly diagnosed and treated effectively. However, occasionally one is faced with patients who are refractory to medical treatment and have no obvious rhinologic, laryngeal or pulmonary cause. STUDY DESIGN AND SETTING: We conducted a review of the literature. METHODS: We present a thorough review of the current medical literature exploring the complex neurologic mechanisms involved in the production of cough and the relationship between gastroesophageal reflux disease, vagal neurapathy, and paradoxical vocal fold motion. RESULTS: The diagnosis and successful treatment of chronic cough can be complex. It requires a thorough understanding of the neurologic mechanisms behind cough excitation and suppression. Successful treatment strategies include aggressive management of the patient's reactive airway disease, gastroesophageal reflux disease, and, in select cases, paradoxical vocal fold motion. This may involve a well-coordinated effort among pulmonologists, otolaryngologists, gastroenterologists, and speech pathologists. CONCLUSION: Gastroesophageal reflux disease, vagal neuropathy, and paradoxical vocal fold motion are additional causes of chronic cough and disordered breathing that need to be considered, in the absence of obvious laryngotracheal and/or rhinologic pathology. A high index of suspicion is essential in making the diagnosis and formulating an effective multidisciplinary treatment plan for these patients.  相似文献   
993.
994.
Sexual deviation disorders, or paraphilias, are diagnosable psychiatric syndromes manifested by 1) recurrent fantasies about deviant sex, 2) intense associated cravings, and 3) stereotypic behavioral responses. Pedophiles seek out children in response to their erotic thoughts and urges, whereas exhibitionists expose themselves. Paraphiliac syndromes ordinarily follow a chronic course and may be associated with biological pathology, but etiological factors are poorly understood. Treatment becomes a consideration when the well-being or rights of others are compromised. Proposed treatments have included psychotherapy, behavior therapy, surgery, and medication. Medroxyprogesterone acetate, which reduces testosterone, may diminish sexual preoccupation and urges, making self-control easier.  相似文献   
995.
996.
997.
Many important pharmaceutical agents, including vancomycin, bleomycin, cyclosporin, and several antibiotics, are produced by non‐ribosomal peptide synthetase (NRPS) enzymes in microorganisms. The NRPS pathway produces an extensive library of products using multienzyme complexes acting in an assembly‐line fashion. Engineering an NRPS system to produce an even greater variety of products, some of which may also have beneficial therapeutic value, would be an enormous advantage. Several approaches have been successful in generating novel NRPS products: mutational biosynthesis during which nonnatural substrates are fed to an organism; domain and module swapping between different species to generate hybrid enzymes; and rational site‐directed mutagenesis, based either on phylogeny or computational prediction, intended to switch substrate specificity and produce altered products. This review will highlight the progress in these areas and describe research in the future that will extend the capacity for re‐engineering NRPS systems. Drug Dev. Res. 66:9–18, 2006. © 2006 Wiley‐Liss, Inc.  相似文献   
998.
From March 1990 through January 1991, 47 patients undergoing myocardial revascularization had one (37) or both (10) inferior epigastric arteries (IEA) used as a conduit for bypass with 62 distal anastomoses. The internal thoracic artery (ITA) was used bilaterally in 41 patients and unilaterally in 6 with 100 distal anastomoses. Five patients had a single saphenous vein graft. In total, 167 anastomoses (3.55 per patient) were performed. Single IEA grafts were harvested through a paramedian incision and bilateral grafts, a midline incision. Harvest time was 36.5 minutes for IEA grafts and 29.6 minutes for ITA grafts (p less than 0.0001). Graft length was 11.9 cm for IEA grafts and 16.5 cm for ITA grafts (p less than 0.0001). Distal graft diameter was 2.0 mm for IEA grafts and 2.1 mm for ITA grafts (p less than 0.01). Graft flow was 49.7 mL/min for IEA grafts and 48.7 mL/min for ITA grafts. Microscopic assessment of segments of both the IEA and ITA from 14 patients revealed similar internal elastic laminae and an equal number of fenestrations. Combined intimal and medial thickness was comparable in both conduits. Medial elastic tissue was more prominent in ITA grafts and lacking in eight of the 14 IEA grafts. Gross plaque formation was noted in the proximal 1 to 3 cm of 50% of IEA grafts, but the lumen was not compromised and microscopic thickening was minimal. An unexpected finding was medial calcifications (M?nckeberg's disease) in two of the 14 IEAs without associated atherosclerosis. There was one hospital death, one abdominal wound infection, and one instance of fat necrosis superficial to the sternum.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
999.
Esophageal pH monitoring is the accepted standard for the investigation of gastroesophageal reflux (GER) in adults. A postal questionnaire was sent to 912 United Kingdom paediatric physicians & surgeons. Five hundred forty-seven (61%) replied, with 124 (22.7%) currently using the technique, mostly in conjunction with barium swallow and/or esophagoscopy. The use of pH monitoring to quantify GER was also accepted in principal as being the best determinant of reflux by a further 186 (34%), but as yet was unavailable in their hospitals. Pediatricians were also questioned as to their management of children with GER. The majority were treated medically with a variety of antireflux medication, with only 237 (42%) referring cases for surgery.  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