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   1909篇
  免费   103篇
  国内免费   11篇
耳鼻咽喉   8篇
儿科学   53篇
妇产科学   51篇
基础医学   213篇
口腔科学   24篇
临床医学   150篇
内科学   386篇
皮肤病学   14篇
神经病学   207篇
特种医学   63篇
外科学   317篇
综合类   19篇
预防医学   127篇
眼科学   72篇
药学   114篇
中国医学   7篇
肿瘤学   198篇
  2023年   18篇
  2022年   35篇
  2021年   46篇
  2020年   22篇
  2019年   30篇
  2018年   41篇
  2017年   27篇
  2016年   40篇
  2015年   36篇
  2014年   41篇
  2013年   69篇
  2012年   105篇
  2011年   110篇
  2010年   62篇
  2009年   71篇
  2008年   90篇
  2007年   103篇
  2006年   107篇
  2005年   112篇
  2004年   90篇
  2003年   87篇
  2002年   69篇
  2001年   57篇
  2000年   71篇
  1999年   54篇
  1998年   15篇
  1997年   13篇
  1996年   13篇
  1995年   16篇
  1994年   13篇
  1993年   6篇
  1992年   33篇
  1991年   35篇
  1990年   32篇
  1989年   34篇
  1988年   31篇
  1987年   25篇
  1986年   19篇
  1985年   23篇
  1984年   19篇
  1983年   12篇
  1982年   5篇
  1980年   12篇
  1979年   13篇
  1978年   5篇
  1973年   10篇
  1971年   5篇
  1967年   5篇
  1966年   4篇
  1965年   4篇
排序方式: 共有2023条查询结果,搜索用时 343 毫秒
1.
2.
Systemic effects of intraocular epinephrine during cataract surgery   总被引:2,自引:0,他引:2  
This paper examines the effects of intraocular epinephrine on systemic blood pressure and heart rate during cataract surgery. Sixty-two patients were studied, all of whom received an intraocular infusion of approximately 200 to 300 mL of balanced salt solution with 0.5 mL of epinephrine 1:1000. There was no statistically significant change in blood pressure or heart rate during the time of epinephrine administration. Electrocardiogram monitoring during surgery showed no changes. We believe that dilute concentrations of epinephrine administered during extracapsular cataract extraction pose little threat of systemic toxicity.  相似文献   
3.
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   
4.
Schistosoma mansoni infection, both in humans and in animal models, is known to induce granulomas in the liver and intestine. It has also been reported that in humans the eggs of this parasite can reach the brain, causing psychiatric and neuropathological disorders. Whether this also occurs in rodents is unknown. To answer this question, mice were infected with this parasite and the central nervous system (CNS) examined at various time intervals. The results show that schistosomiasis induced granulomas in several regions of the CNS and increased nerve growth factor (NGF) levels in the cortex, hypothalamus and brain stem, but not in the hippocampus. The infection also caused paw hyperalgesia, as determined by the hot-plate test, and a local increase in NGF, but not in substance P. These findings indicate that the murine model of infection can be used for studying mechanisms leading to human neuroschistosomiasis and suggest that the neuropathological disorders and the sensory deficits observed in human schistosomiasis are associated with impaired levels of NGF in the peripheral and central nervous system. Received: 18 January 1996 / Revised, accepted: 16 April 1996  相似文献   
5.
A recent large increase in Caesarean section (CS) in Italy was the initial stimulus for a study to identify risk factors for CS and, if possible, to suggest strategies to counteract the rise. The study was conducted in three hospitals where a wide range of individual variables was collected from the clinical records and from personal interviews. Crude CS rates and odds ratios were evaluated for each single variable while logistic regression has been used to investigate possible confounding factors. The study involved 1316 consecutive deliveries. Crude CS rates were 29.4%, 15.7% and 16.1%. Variables identified as high risk factors were pre-eclampsia, previous CS, breech and other non-vertex presentations. Antenatal care under an obstetrician working in the same hospital, a low number of antenatal consultations, previous miscarriages, offer (by obstetrician) and request (by women) for CS showed significantly high odds ratios (ORs). Previous live births was strongly negatively associated with CS. No relationship between type of delivery and social status was observed while a physician factor was detected in all three hospitals where rates for different physicians ranged from 0% to 52.8%. Apart from the main medical indications for Caesarean section (previous CS, breech presentation), the results seem to indicate that individual practice style may be an important determinant of the wide variation in the rates of Caesarean delivery. While this may have been suspected before this study, these results are the first hard data to indicate that, in Italy, CS is widely performed for non-medical reasons.  相似文献   
6.
7.
The effects of central administration of calcitonin gene-related peptide (CGRP, 1 or 100 ng/rat) on behavioral and biochemical parameters related to the extrapyramidal motor system were investigated in male rats. The peptide-induced catalepsy occurred only at the dose of 100 ng/rat and hypomotility at both doses used. Calcitonin gene-related peptide increased haloperidol-induced catalepsy and decreased apomorphine-induced hypermotility at the doses of 1 and 100 ng/rat. Although these behaviors are related to dopamine, no significant change of striatal DA or DOPAC concentration were observed after central administration of the peptide. Other neurotransmitters may be directly or indirectly involved in these behavioral effects of CGRP.  相似文献   
8.
9.
The purpose of this study was to determine if the addition of potassium to reinfusion cold blood cardioplegia (CBC) offers an advantage over cold blood alone. Forty patients matched for age, left ventricular function, extent of coronary disease and number of vessels bypassed were prospectively randomized. Each patient received an initial dose of CB C (10 cc/kg) with potassium. Group I patients (n=23) received subsequent infusions of CBC (5 cc/kg) containing potassium while Group II patients (n=17) received cold blood only. The cross-clamp time, mean infusate volume and temperature were not significantly different in the two groups. Following reperfusion, the cardiac index and the CPK isoenzyme release at 0.5, 1, 8, and 12 h after cross-clamp release were not significantly different between the groups. The postoperative appearance of new Q-waves, inotropic agent requirement, and reversal of the lactate dehydrogenase (LDH) isoenzyme ratio were also not significantly different in the two groups. The study demonstrated that following initial arrest with potassium, cold blood is equally as effective as potassium blood cardioplegia in protecting the ischemic myocardium.  相似文献   
10.
Multiple penile horns: case report and review   总被引:1,自引:0,他引:1  
We report a case of unusually large multiple penile horns following removal of condylomata acuminata. Penile horns can grow rapidly, although malignant degeneration is uncommon. Wide excision with deep biopsy of skin at the base of the lesion probably is appropriate treatment.  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