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   22988篇
  免费   1619篇
  国内免费   47篇
耳鼻咽喉   384篇
儿科学   686篇
妇产科学   413篇
基础医学   3261篇
口腔科学   356篇
临床医学   2206篇
内科学   4708篇
皮肤病学   893篇
神经病学   2358篇
特种医学   865篇
外国民族医学   2篇
外科学   3476篇
综合类   215篇
一般理论   5篇
预防医学   1608篇
眼科学   368篇
药学   1454篇
中国医学   34篇
肿瘤学   1362篇
  2023年   114篇
  2022年   115篇
  2021年   328篇
  2020年   212篇
  2019年   280篇
  2018年   624篇
  2017年   428篇
  2016年   541篇
  2015年   593篇
  2014年   585篇
  2013年   930篇
  2012年   1551篇
  2011年   1588篇
  2010年   763篇
  2009年   623篇
  2008年   1222篇
  2007年   1333篇
  2006年   1277篇
  2005年   1202篇
  2004年   1144篇
  2003年   1044篇
  2002年   1018篇
  2001年   587篇
  2000年   563篇
  1999年   554篇
  1998年   167篇
  1997年   125篇
  1996年   104篇
  1995年   121篇
  1994年   121篇
  1993年   96篇
  1992年   254篇
  1991年   292篇
  1990年   237篇
  1989年   236篇
  1988年   202篇
  1987年   213篇
  1986年   200篇
  1985年   211篇
  1984年   138篇
  1983年   141篇
  1981年   95篇
  1979年   140篇
  1978年   101篇
  1977年   93篇
  1975年   117篇
  1974年   122篇
  1973年   101篇
  1972年   111篇
  1971年   99篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
91.
92.
93.
Abstract Whiplash injury of the cervical spine is a frequent issue in medical expertises and causes enormous consequential costs for motor insurance companies. Some authors accuse posttraumatic changes of alar ligaments to be causative of consequential disturbances, although biomechanical experiments achieve contradictory results and neuropsychiatric studies do not support this thesis. MRI provides excellent visualization of alar ligaments. However, signal alterations of alar ligaments must be differentiated from common normal variants. Functional MRI provides no diagnostic yield.   相似文献   
94.
Quality of life is impaired in patients with epilepsy and can be improved by effective therapy. Randomised clinical trials have shown that lamotrigine treatment is associated with improved quality of life. However, little information is available on quality of life or treatment effects in patients with epilepsy in the general population. The objective of this study was to estimate the impact of lamotrigine on quality of life in a naturalistic treatment setting. The study included adult patients with epilepsy in whom lamotrigine therapy was initiated. Each subject completed the Quality of Life in Epilepsy Inventory (QOLIE)-31 quality of life questionnaire at inclusion and at a follow-up visit in the next 4 months. Demographic information and medical history were provided by the investigator. These were evaluated as potential determinants of change in quality of life using logistic regression. Three hundred and forty-one patients were evaluated, 192 starting lamotrigine in combination with another drug, 90 as a first-line monotherapy, 45 as a switch from another drug and 14 as a reduction to monotherapy from a previous combination. Baseline scores on the QOLIE-31 ranged from 53.8 in the combination group to 69.5 in the first-line group. 34.6% of patients were considered to be responders, with no significant differences between treatment regimen. Most improvement was seen for the energy-fatigue and medication effects subscales and, for the first-line group, seizure worry. Seizure type was the only determinant of improvement of quality of life identified. In conclusion, lamotrigine treatment is associated with improved quality of life, regardless of treatment regimen.  相似文献   
95.
OBJECTIVE: We consider the short- and long-term outcomes of the repair of the isolated partial atrioventricular (AV) septal defect to determine the role played by the atypical forms on the initial AV valve replacement and on the risk of reoperation. METHODS: Two hundred and eight patients underwent an operation for this malformation between 1974 and 2001. Clinical and echocardiographic examinations were performed on all patients, the AV valve regurgitation was graded from 1 to 4 and a residual interatrial shunt was sought. Median age at the intervention was 5.8 years (3 months to 67 years). RESULTS: Median follow-up time was 7.5 years (range 0-22.6 years). The cumulative 30-day, 5- and 20-year survival rates were 96.5, 95.4 and 94.6%, respectively. AV valve replacement was associated with a high mortality (P<0.001). A reoperation was performed on 12 patients (5.7%) including six patients within less than a 30-day period, especially to repair residual AV valve regurgitation. We performed four AV valve repairs by annuloplasty and six AV valve replacements. Two patients who had initially undergone an AV valve replacement underwent a reoperation for valve thrombosis. The cumulative 30-day, 5- and 20-year rates of freedom from reoperation were 96.5, 93.6 and 83%, respectively. An atypical form was present in 24 patients (11.5%) and was a risk factor for initial AV valve replacement (P<0.001) and for reoperation (P<0.001). A complete AV block occurred in 13 patients (6.2%), all of them within a 30-day period. The AV valve replacement was a high risk factor for a complete AV block (P<0.001). At the end of our study 180 patients (96%) were in NYHA I and 8 in NYHA II. CONCLUSIONS: The morbi-mortality of the isolated partial AV septal defect is primarily perioperative and is linked with the presence of an atypical form of the lesion. This atypical form was the main reason for reoperation for AV valve regurgitation. The AV valve replacement was associated with a high mortality and with the occurrence of complete AV block. Using a standardized technique, the AV septal defect can be repaired with excellent long-term clinical and echographic results.  相似文献   
96.
97.
98.
Acute vascular occlusion after percutaneous transluminal coronary angioplasty (PTCA) often necessitates a prompt aortocoronary bypass-operation (CABG). Alternatively, a re-PTCA can be attempted. In 1500 consecutive patients there was acute symptomatic occlusion due to PTCA 5 min to 16 h after the operation in 47 cases (3.1%). An immediate re-PTCA was attempted in all cases. Results: Reopening was successful in 43 of 47 cases (91%): in 15 patients (30%) within 30 min, in 36 patients (68%) within 60 min and in 42 patients (89%) within 90 min. In eight patients there was early re-occlusion 30 min to 20 h after re-PTCA, necessitating acute CABG in four patients. In 35 patients with re-PTCA the vessel remained open. Re-stenosis occurred within 1 to 10 days in 10 patients, and in additional 12 patients after 2-4 months. In most cases an additional PTCA was successful. Complications: Six patients had an emergency CABG (three with an exchange wire as a stent in the dissected coronary artery). Three patients died (one after CABG); 14 patients experienced myocardial infarction (30%) (in three of these 14 the infarct was large). Conclusion: Acute vascular occlusion after PTCA can successfully be treated by re-PTCA in four of five cases. However a rate of re-stenosis of about 60% is to be anticipated. Reperfusion with re-PTCA is fast and in these patients with transmural ischemia there are obviously less complications in comparison to emergency CABG after PTCA. 60% of the patients remain symptom free or markedly improved and without infarction or emergency CABG after 4 months.  相似文献   
99.
A 54 year-old woman developed approximately 150 generalized glomus tumors since she had been 23 years old. Painful tumors showed more glomus cells than those being not painful. Furthermore, the patient suffered from persisting congenital capillary hemangioma (strawberry mark). Histological examination revealed that glomus cells were located in the vessel walls. The large amount of Dopa found in the glomus tumor tissue supports the assumption that it may be innervated by adrenergic efferent nerves.  相似文献   
100.
An experimental drug, 1-(1,3-benzodioxol-5-ylcarbonyl)piperidine, that facilitates glutamatergic transmission in brain after systemic administration was tested for its effects on the induction of long-term potentiation in the hippocampus of rats. Intraperitoneal injections of the drug markedly increased the degree and duration of long-term potentiation; similar results were obtained with an analogue of 1-(1,3-benzodioxol-5-ylcarbonyl)piperidine that was also found to improve retention of memory in a radial maze task and in an odor-matching problem. These results define tools for enhancing long-term potentiation in vivo and confirm an important prediction from the hypothesis that long-term potentiation is a substrate of memory.  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