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   2278篇
  免费   114篇
  国内免费   81篇
耳鼻咽喉   107篇
儿科学   114篇
妇产科学   41篇
基础医学   279篇
口腔科学   33篇
临床医学   290篇
内科学   554篇
皮肤病学   84篇
神经病学   113篇
特种医学   312篇
外国民族医学   1篇
外科学   212篇
综合类   36篇
预防医学   85篇
眼科学   11篇
药学   111篇
肿瘤学   90篇
  2023年   8篇
  2021年   31篇
  2020年   9篇
  2019年   36篇
  2018年   43篇
  2017年   23篇
  2016年   29篇
  2015年   36篇
  2014年   31篇
  2013年   75篇
  2012年   75篇
  2011年   78篇
  2010年   81篇
  2009年   70篇
  2008年   57篇
  2007年   103篇
  2006年   59篇
  2005年   74篇
  2004年   51篇
  2003年   53篇
  2002年   64篇
  2001年   51篇
  2000年   64篇
  1999年   55篇
  1998年   100篇
  1997年   106篇
  1996年   110篇
  1995年   88篇
  1994年   91篇
  1993年   79篇
  1992年   60篇
  1991年   59篇
  1990年   54篇
  1989年   58篇
  1988年   57篇
  1987年   47篇
  1986年   50篇
  1985年   49篇
  1984年   21篇
  1983年   25篇
  1982年   22篇
  1981年   24篇
  1980年   19篇
  1978年   9篇
  1977年   15篇
  1976年   13篇
  1975年   11篇
  1974年   7篇
  1971年   6篇
  1970年   6篇
排序方式: 共有2473条查询结果,搜索用时 15 毫秒
1.
2.
3.
Between 1977 and 1987, 27 consecutive patients (16 men, 11 women, mean age 66 years, range 54 to 75 years) with ventricular septal rupture complicating acute myocardial infarction underwent surgical repair. The purpose of this retrospective study was to analyse the post-operative mortality factors from clinical, haemodynamic and operative data in all patients and also from coronary angiographic data in 23/27 patients whose haemodynamic status allowed this type of exploration. Seventeen patients (63 p. 100) died during the first post-operative month, 10 survived and were discharged. Factors that influenced the prognosis were: (1) inferiorly-located necrosis associated with a 75 p. 100 mortality rate (9 out of 12 patients), as opposed to 53 p. 100 (8 out of 15 patients) with anterior necrosis; (2) right ventricular dysfunction, observed in 83 p. 100 of patients with inferior necrosis and 53 p. 100 with anterior necrosis, which was responsible for 7 out of 9 deaths in the inferior necrosis subgroup and contributed to 3 out of 8 deaths in the anterior necrosis subgroup; this established a cause-effect relationship between right ventricular function and the overmortality of patients with inferior necrosis; (3) independently of the haemodynamic status, two- and three-vessel lesions (56 p. 100 of all lesions) which had an 84 p. 100 mortality rate as opposed to 40 p. 100 with one-vessel lesions; (4) the presence of a state of shock which was associated with a 78 p. 100 mortality rate as opposed to 55 p. 100 in patients without shock. We conclude that when permitted by the patient's haemodynamic status coronary angiography should be part of the pre-operative evaluation to assess the operative risk and guide the surgical procedure.  相似文献   
4.
5.
6.
7.
8.
BACKGROUND: Knowledge of the prevalence of peripheral arterial disease (PAD) in patients with chronic renal failure (CRF) is limited because of a lack of uniformity in disease definition and recognition. Furthermore, little is known of the prevalence of medial arterial calcification (MAC) in patients with CRF. Our goal is to study the prevalence of PAD and MAC defined by ankle brachial index (ABI) or toe brachial index (TBI) measurements in a Finnish population of patients with CRF consisting of predialysis and dialysis patients, as well as renal transplant recipients. METHODS: We examined 136 patients with CRF and 59 control subjects. Fifty-nine of the patients with CRF had moderate to severe predialysis CRF, 36 patients were on dialysis treatment, and 41 were renal transplant recipients. Mean age of patients was 51.9 +/- 11.5 years, and 39 patients (29%) had diabetes. ABI and TBI were measured by means of photoplethysmography. The definition of PAD required an ABI value of 0.90 or less, a TBI value of 0.60 or less, or a previous positive lower-extremity angiogram result. ABI values of 1.3 or greater or incompressible arteries at ankle level indicated MAC. The presence of claudication was determined by an interview. RESULTS: Prevalences of PAD on this study were 22.0% in patients with predialysis CRF, 30.6% in patients on dialysis treatment, 14.6% in renal transplant recipients, and 1.7% in the control group (P = 0.001). Prevalences of MAC were 23.7%, 41.7%, 23.1%, and 3.4% (P < 0.001), respectively. Only 9 patients had claudication, and 6 of those patients had PAD. CONCLUSION: Both asymptomatic PAD and MAC are common in patients with CRF. Therefore, we recommend the use of both ABI and TBI measurements in the evaluation of PAD in patients with CRF.  相似文献   
9.
Glutamate (GLU)-receptor subtypes, (quisqualate (QA)-, kainate (KA)-, N- methyl-D-aspartate (NMDA)-receptors) and the phencyclidine sites localized in the ion-channel associated to the NMDA-receptors, were studied by autoradiography in the hippocampus of rats subjected to a convulsive dose of the acetylcholinesterase inhibitor soman (0-, 1,2,2-trimethylpropyl methylphosphonofluoridate). In intoxicated rats, a significant increase in L-[3H]-GLU binding occurred within the first 40 min of seizures in the hippocampal CA3 and CA1 areas. Whereas binding to KA- and NMDA-receptors remained unchanged, L-[3H]-GLU binding to CA3 QA-receptors increased by 31 and 50% respectively after 10 and 40 min of seizures. In CA1, the change in QA-receptors was delayed (+30% after 40 min) and accompanied by an increase in the phencyclidine site binding capacity, reflecting the probable concomitant opening of NMDA ion-channels. These findings confirmed the previously suspected involvement of GLU in the earliest stages of soman-induced seizures, and suggested that, in hippocampus, the primary activation of QA-receptors in the CA3 region could lead to the secondary recruitment of combined non-NMDA (QA) and NMDA mechanisms in CA1.  相似文献   
10.
We used arthrotomography to study the glenoid labrum in 114 patients. Sixty-nine of the patients had anatomic instability of the shoulder (including recurrent dislocation and subluxation of the shoulder), and 45 patients had functional instability of the shoulder (denoted by chronic pain, clicking of the joint, and the sensation that an unstable condition exists without the objective signs of it). Labral tears were revealed arthrotomographically in 86% of the patients with anatomic instability, while only 40% of the patients with functional instability had labral abnormalities, and these were primarily of minor severity. Fifty-six patients (44 of whom had anatomic instability; 12, functional instability) required surgery. The surgical findings were correlated with the arthrotomographic findings, and no false-positive results were revealed. However, arthrotomography demonstrated only part of the pathologic condition of two patients. These results confirm that there is a strong correlation between labral pathologic conditions and anatomic instability of the shoulder. Arthrotomographic studies have a great impact on the selection of therapy in cases of both anatomic and functional instability of the shoulder.  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