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   1603637篇
  免费   131683篇
  国内免费   2586篇
耳鼻咽喉   21670篇
儿科学   53010篇
妇产科学   46318篇
基础医学   228065篇
口腔科学   47214篇
临床医学   141111篇
内科学   315058篇
皮肤病学   34103篇
神经病学   130245篇
特种医学   64776篇
外国民族医学   474篇
外科学   244158篇
综合类   39741篇
现状与发展   3篇
一般理论   558篇
预防医学   123017篇
眼科学   36479篇
药学   121449篇
  3篇
中国医学   2975篇
肿瘤学   87479篇
  2018年   14808篇
  2016年   12938篇
  2015年   15065篇
  2014年   20699篇
  2013年   31435篇
  2012年   42657篇
  2011年   44845篇
  2010年   26400篇
  2009年   25360篇
  2008年   43075篇
  2007年   45323篇
  2006年   46127篇
  2005年   44757篇
  2004年   44175篇
  2003年   42243篇
  2002年   41358篇
  2001年   75718篇
  2000年   78385篇
  1999年   66428篇
  1998年   17748篇
  1997年   16354篇
  1996年   16335篇
  1995年   16042篇
  1994年   15081篇
  1993年   14234篇
  1992年   55468篇
  1991年   53811篇
  1990年   52591篇
  1989年   50863篇
  1988年   47267篇
  1987年   46601篇
  1986年   44313篇
  1985年   42873篇
  1984年   32058篇
  1983年   27580篇
  1982年   16165篇
  1981年   14455篇
  1980年   13573篇
  1979年   30482篇
  1978年   21078篇
  1977年   17778篇
  1976年   16709篇
  1975年   17590篇
  1974年   21502篇
  1973年   20686篇
  1972年   18868篇
  1971年   17784篇
  1970年   16296篇
  1969年   15274篇
  1968年   13957篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Several case reports have implicated Ginkgo biloba in clinically adverse bleeding disorders. Ginkgo biloba has been reported to increase pain-free walking distance among patients with peripheral artery disease (PAD). Standard PAD therapy includes 325 mg/day aspirin. The objective of this study was to examine potential adverse effects of concomitant aspirin and Ginkgo biloba on platelet function. Ginkgo biloba (EGb 761, 300 mg/day) was compared with placebo for effects on measures of platelet aggregation among adults consuming 325 mg/day aspirin in a randomized, double-blind, placebo-controlled, parallel design trial of 4-week duration. Participants were adults, age 69 +/- 10 years, with PAD or risk factors for cardiovascular disease. Outcome measures included platelet function analysis (PFA-100 analyzer) using ADP as an agonist (n = 26 placebo; n = 29 ginkgo), and platelet aggregation using ADP, epinephrine, collagen and ristocetin as agonists (n = 21 placebo; n = 23 ginkgo). Participants kept daily logs of bleeding or bruising episodes. There were no clinically or statistically significant differences between treatment groups for any agonists, for either PFA-100 analysis or platelet aggregation. Reports of bleeding or bruising were infrequent and similar for both study groups. In conclusion, in older adults with PAD or cardiovascular disease risk, a relatively high dose of Ginkgo biloba combined with 325 mg/day daily aspirin did not have a clinically or statistically detectable impact on indices of coagulation examined over 4 weeks, compared with the effect of aspirin alone. No adverse bleeding events were observed, although the trial was limited to a small sample size.  相似文献   
992.
BRING ADDICTION TREATMENT OUT OF THE CLOSET   总被引:1,自引:1,他引:0  
  相似文献   
993.
The co-existence of fungal elements in allergic nasal Polyposis, has given rise to a distinct clinical entity known as ‘Allergic fungal sinusitis ’ (AF’S). Many a time, these fungal elements may not be diagnosed pre-operatively by routine diagnostic nasal endoscopy or CT scan of paranasal sinuses, due to the florid presentation of nasal polyps, which usually obscure the underlying fungal pathology. The diagnosis is often made intra-operatively. The post-operative confirmation of AFS is by histopathology, fungal smear, fungal culture, allergic murin study and fungal specific IgE titres. We report a series often such cases done in our institution, which highlight that AFS should be considered as a differential diagnosis in Sinonasal Polyposis cases, for their effective management.  相似文献   
994.
Hepatic encephalopathy is a reversible state of altered cognition that may occur in patients with acute or chronic liver disease or porto-systemic shunt, and in which known neurological or psychiatric signs may develop. Nitrogenated substances from intestinal digestion reach the brain without being cleared by their passage through the liver due to the presence of porto-systemic shunt. We report two cases of patients with porto-systemic shunt diagnosed with recurrent chronic hepatic encephalopathy refractory to conventional medical treatment. They were satisfactorily treated with shunt embolization using interventionist radiology techniques.  相似文献   
995.
BACKGROUND CONTEXT: The effectiveness of spinal surgery as a treatment option is currently evaluated through the assessment of patient-reported outcomes (PROs). The minimum clinically important difference (MCID) represents the smallest improvement considered worthwhile by a patient. The concept of an MCID is offered as the new standard for determining effectiveness of a given treatment and describing patient satisfaction in reference to that treatment. PURPOSE: Our goal is to review the various definitions of MCID and the methods available to determine MCID. STUDY DESIGN: The primary means of determining the MCID for a specific treatment are divided into anchor-based and distribution-based methods. Each method is further subdivided and examined in detail. METHODS: The overall limitations of the MCID concept are first identified. The basic assumptions, statistical biases, and shortcomings of each method are examined in detail. RESULTS: Each method of determining the MCID has specific shortcomings. Three general limitations in the accurate determination of an MCID have been identified: the multiplicity of MCID determinations, the loss of the patient's perspective, and the relationship between pretreatment baseline and posttreatment change scores. CONCLUSIONS: An ideal means of determining the MCID for a given intervention is yet to be determined. It is possible to develop a useful method provided that the assumptions and methodology are initially declared. Our efforts toward the establishment of a MCID will rely on the establishment of specific external criteria based on the symptoms of the patient and treatment intervention being evaluated.  相似文献   
996.
Exercise advice is a well established component of the conservative management of intermittent claudication. Supervised programmes of exercise remain relatively uncommon and are provided mainly in secondary care. This review outlines the evidence for the effectiveness of different exercise regimens and the relative benefits of exercise therapy, where comparisons have been made with medical therapy, angioplasty and surgery.  相似文献   
997.
998.
999.
1000.
Intramedullary implants have decisive advantages in the treatment of femoral fractures in the vicinity of the hip joint: a torque that leads to a less pronounced varus position, implantation in the course of the relevant forces, and primary stability in the case of both stable and unstable fractures. Because of the constant developments in the implants available and the frequent failure to differentiate between stable and unstable fractures, some of the recommendations in the literature seem to contradict each other. However, precise analysis of the literature data show that stable fractures can be adequately treated with any technique, while unstable fractures fall in the domain of nailing systems. Since it is not possible to distinguish unequivocally between stable and unstable fractures, all trochanteric and subtrochanteric femoral fractures should be treated with a cephalomedullary nailing system.  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