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   20261篇
  免费   1214篇
  国内免费   204篇
耳鼻咽喉   165篇
儿科学   334篇
妇产科学   330篇
基础医学   2880篇
口腔科学   673篇
临床医学   1855篇
内科学   5324篇
皮肤病学   231篇
神经病学   2074篇
特种医学   705篇
外科学   2983篇
综合类   63篇
一般理论   3篇
预防医学   1008篇
眼科学   257篇
药学   1603篇
中国医学   68篇
肿瘤学   1123篇
  2023年   131篇
  2022年   339篇
  2021年   573篇
  2020年   400篇
  2019年   507篇
  2018年   625篇
  2017年   456篇
  2016年   520篇
  2015年   596篇
  2014年   791篇
  2013年   965篇
  2012年   1536篇
  2011年   1580篇
  2010年   873篇
  2009年   784篇
  2008年   1227篇
  2007年   1324篇
  2006年   1147篇
  2005年   1215篇
  2004年   1112篇
  2003年   988篇
  2002年   949篇
  2001年   224篇
  2000年   223篇
  1999年   229篇
  1998年   223篇
  1997年   154篇
  1996年   113篇
  1995年   115篇
  1994年   107篇
  1993年   100篇
  1992年   144篇
  1991年   97篇
  1990年   88篇
  1989年   66篇
  1988年   69篇
  1987年   62篇
  1986年   66篇
  1985年   54篇
  1984年   53篇
  1983年   40篇
  1982年   37篇
  1981年   35篇
  1980年   34篇
  1978年   21篇
  1973年   24篇
  1970年   24篇
  1935年   21篇
  1925年   23篇
  1922年   22篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
Background: Tight perioperative control of blood glucose improves the outcome of diabetic patients undergoing cardiac surgery. Because stress response and cardiopulmonary bypass can induce profound hyperglycemia, intraoperative glycemic control may become difficult. The authors undertook a prospective cohort study to determine whether poor intraoperative glycemic control is associated with increased intrahospital morbidity.

Methods: Two hundred consecutive diabetic patients undergoing on-pump heart surgery were enrolled. A standard insulin protocol based on subcutaneous intermediary insulin was given the morning of the surgery. Intravenous insulin therapy was initiated intraoperatively from blood glucose concentrations of 180 mg/dl or greater and titrated according to a predefined protocol. Poor intraoperative glycemic control was defined as four consecutive blood glucose concentrations greater than 200 mg/dl without any decrease in despite insulin therapy. Postoperative blood glucose concentrations were maintained below 140 mg/dl by using aggressive insulin therapy. The main endpoints were severe cardiovascular, respiratory, infectious, neurologic, and renal in-hospital morbidity.

Results: Insulin therapy was required intraoperatively in 36% of patients, and poor intraoperative glycemic control was observed in 18% of patients. Poor intraoperative glycemic control was significantly more frequent in patients with severe postoperative morbidity (37% vs. 10%; P < 0.001). The adjusted odds ratio for severe postoperative morbidity among patients with a poor intraoperative glycemic control as compared with patients without was 7.2 (95% confidence interval, 2.7-19.0).  相似文献   

12.
13.
14.
15.
Naloxone, an opioid peptide antagonist, has been reported to facilitate voiding in neurologic bladder disorders, but its effects on the neural micturition reflex arc are poorly understood. We studied the effect of naloxone in 34 male adult cats, spinalized at C5-C6 level 7 to 119 days previously. Each cat served as its own control. The following tests were performed: Urethral pressure profiles, cystosphincterograms with the urethro-vesical junction opened and closed and mechanograms of the detrusor, and the circular and longitudinal urethral muscles. The study included (1) the effects of anesthesia of the bladder and pelvic nerve, as well as that of the urethral and pudendal nerves; (2) the action of naloxone; and (3) the action of oxymorphone. Our results demonstrated that naloxone (1) increased somatic (osteotendinous and nociceptive) reflexes and aggravated spasticity; (2) increased vegetative micturitional and sexual reflexes, in particular the urethra-urethral contraction reflex, aggravating the spasmodic contractions of the external sphincter; and (3) increased the frequency and intensity of the mass reflex. In consequence, we suggest that naloxone is contraindicated in cases of spinal cord lesions with detrusor-sphincter dyssynergia syndrome.  相似文献   
16.
17.
OBJECTIVE: Biventricular pacing has demonstrated improvement in cardiac function in treating congestive heart failure (CHF). Two different operative strategies (coronary sinus vs. epicardial stimulation) for left ventricular (LV) pacing were compared. METHODS: Since April 1999, a total of 86 patients (pts, age: 63+/-10 years) with depressed systolic LV function (mean ejection fraction 24+/-9%), left bundle-branch-block (mean QRS 182+/-22 ms) and congestive heart failure NYHA III or higher were enrolled. For biventricular stimulation coronary sinus (CS) leads were placed in 79 pts. Nine of these devices were converted to surgical epicardial LV-leads, because of CS-lead failure. In 7 patients epicardial LV-leads were initially implanted surgically, accounting for a total of 16 pts with surgical placed epicardial steroid-eluting LV-leads. For these, a limited left-lateral thoracotomy (7+/-4 cm) was used. Thirty-three (38%) pts had an indication for a defibrillator. The mean follow-up time was 16.4+/-15.4 months (0.1-45 months), representing 107.1 patient-years. RESULTS: In the biventricular pacing mode, QRS duration decreased to 143+/-16 ms (P<0.001). Threshold capture of the CS-leads increased significantly compared to surgically placed epicardial leads (18 month control: 2.2+/-1.4V/0.5 ms vs. 0.7+/-0.3V/0.5 ms), which had no increase in threshold (P<0.001). At the 18 month follow-up 7 CS-leads had a threshold of >4V/0.5 ms vs. epicardial leads which were under 1.1V/0.5 ms, except for one (1.8V/0.5 ms). After CS-lead implantation 25 LV-lead related complications occurred, (failed implantation, CS-dissection, loss of pacing capture, diaphragm stimulation or lead dislodgment), vs. one dislodgement after surgical epicardial lead placement (P<0.05). Correct lead positioning (obtuse marginal branch area) was achieved in all surgical epicardial placements but only in 70% with CS-leads (P<0.03). In the follow up period, 9 pts died (4 cardiac related). Heart transplantation was necessary in 4 pts due to deterioration of the cardiomyopathy. CONCLUSIONS: Surgical epicardial lead placement revealed excellent long-term results and a lower LV-related complication rate compared to CS-leads. Although, the approach via limited thoracotomy for biventricular pacing is associated with 'more surgery', it is a safe and reliable technique and should be considered as an equal alternative.  相似文献   
18.
The epsilon-sarcoglycan gene (SGCE) on human chromosome 7q21 has been reported to be a major locus for inherited myoclonus-dystonia. Linkage to the SGCE locus has been detected in the majority of families tested, and mutations in the coding region have been found recently in families with autosomal dominant myoclonus-dystonia. To evaluate the relevance of SGCE in myoclonus-dystonia, we sequenced the entire coding region of the epsilon-sarcoglycan gene in 16 patients with either sporadic or familial myoclonus-dystonia. No mutations were found. This study suggests that epsilon-sarcoglycan does not play an important role in sporadic myoclonus-dystonia and supports genetic heterogeneity in familial cases.  相似文献   
19.
20.
Abstract End-stage liver disease caused by the hepatitis C virus is a major indication for liver transplantation. However, recurrence of hepatitis in the graft is a major issue. HCV re-infection after transplantation is almost constant, and recent data confirm that it significantly impairs patient and graft survival. Factors that may influence disease severity and consequent progression of HCV graft injury remain unclear. Chronic HCV infection develops in 60%–80% of patients, and 6%–28% ultimately progress to cirrhosis within 5 years. Pre-transplantation antiviral treatment is not easily related to poor tolerance. Attempts to administer prophylactic post-transplantation antiviral treatment are under evaluation but are limited by antiviral drug side effects. Treatment of established graft lesions with interferon or ribavirin as single agents has been disappointing. Combination therapy gave promising results, with sustained virological response in 25% of patients, but indications, modality and duration of treatment should be assessed.  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