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   2858篇
  免费   162篇
  国内免费   26篇
耳鼻咽喉   16篇
儿科学   147篇
妇产科学   58篇
基础医学   339篇
口腔科学   54篇
临床医学   155篇
内科学   647篇
皮肤病学   25篇
神经病学   145篇
特种医学   106篇
外科学   653篇
综合类   12篇
预防医学   54篇
眼科学   101篇
药学   231篇
中国医学   31篇
肿瘤学   272篇
  2024年   2篇
  2023年   16篇
  2022年   35篇
  2021年   87篇
  2020年   42篇
  2019年   66篇
  2018年   86篇
  2017年   71篇
  2016年   73篇
  2015年   96篇
  2014年   119篇
  2013年   126篇
  2012年   164篇
  2011年   214篇
  2010年   105篇
  2009年   116篇
  2008年   172篇
  2007年   209篇
  2006年   181篇
  2005年   194篇
  2004年   212篇
  2003年   166篇
  2002年   186篇
  2001年   28篇
  2000年   29篇
  1999年   23篇
  1998年   26篇
  1997年   32篇
  1996年   25篇
  1995年   27篇
  1994年   17篇
  1993年   9篇
  1992年   12篇
  1991年   9篇
  1990年   9篇
  1989年   4篇
  1988年   7篇
  1987年   6篇
  1985年   8篇
  1984年   4篇
  1983年   3篇
  1982年   7篇
  1981年   2篇
  1980年   4篇
  1979年   4篇
  1976年   4篇
  1969年   1篇
  1968年   1篇
  1966年   1篇
  1956年   2篇
排序方式: 共有3046条查询结果,搜索用时 11 毫秒
51.
Living-related liver transplantation (LRLT) is a relatively new surgical modality that has developed, in part, to overcome the shortage of available cadaveric livers for transplantation and as a method to provide liver graft implants from living donors for patients end-stage with liver disease in areas where the use of cadaveric livers is not yet practiced or permitted. Since 1988 almost 500 LRLTs have been performed globally. The safety of donors who provide a portion of their liver for grafting is of utmost concern, and only one donor death from this procedure has been reported in the literature. Postoperative survival in recipients depends on their pretransplant physical status, but emergency patients in rapid need of a liver have a poorer survival than elective LRLT patients for whom survival is about 80%. Children and infants are the main recipients of LRLTs, but adult patients particularly in Japan, are increasing in number, and present indications for LRLT surgery include not only cholestatic end-stage liver diseases but also metabolic disorders affecting the liver and emergency LRLTs for fulminant hepatic failure. Many ethical problems relating to the concept of liver transplantation, donor liver source, recipient selection, and reimplantation have yet to be resolved. But we believe that LRLTs and cadaveric liver transplantations are saving lives and that the practice should be continued.  相似文献   
52.
Mondini dysplasia is rare, but has an important association with recurrent bacterial meningitis. We herein describe the case of a 3‐year‐old girl with unilateral sensorineural hearing loss who presented with three independent episodes of bacterial meningitis within 8 months. Temporal bone computed tomography indicated the characteristic features of Mondini dysplasia in the right inner ear. This was treated by surgical closure of the inner ear defect via oval window and additional vaccination was administered. Appropriate vaccination might prevent the recurrent bacterial meningitis associated with Mondini dysplasia.  相似文献   
53.
The use of bile acid dissolution therapy in extracorporeal shockwave lithotripsy of gallstones, remains controversial. Our study examined whether chemolitholysis after sufficient disintegration enhanced stone clearance within 6 months of the first lithotripsy. A total of 143 patients who developed one to three radiolucent stones measuring⪯30 mm in diameter were randomly separated into two treatment groups: 47% were given lithotripsy alone, and 53% lithotripsy plus ursodeoxycholic acid (UDCA). Repeated piezoelectric lithotripsy was given, with no limit on the total number of treatment sessions, to pulverize or disintegrate stones into fragments<3 mm. Stones were disintegrated in 97% of all patients, and the fragments were ⪯2 mm in 50% of these patients. According to an intention-to-treat analysis, 52% in the lithotripsy alone group and 58% in the UDCA group were free of stones 6 months after the first lithotripsy (P=0.61). Of the patients with fragments⪯2 mm, 71% in the former and 86% in the latter group were free of stones 6 months after the first lithotripsy, with no significant difference between the groups. Biliary pain occurred in 25% of all patients, including 3 with acute cholecystitis. We concluded that the sufficient disintegration of gallstones achieved with repeated lithotripsy enhanced the early clearance of fragments, regardless of whether chemolitholysis was employed.  相似文献   
54.

Background

Diabetes has been reported as a comorbidity of chronic obstructive pulmonary disease (COPD) in Western countries, but it has not been demonstrated in epidemiological reports in Japan. The purpose of this study was to clarify whether the relationship between airflow obstruction and diabetes can be confirmed in a Japanese general population.

Methods

From 2004 to 2006, blood sampling and pulmonary function tests were performed on 3045 people over the age of 40 years in annual health check-ups held in Takahata, Yamagata Prefecture, Japan. Pulmonary function was re-evaluated in 2009 and 2011.

Results

The prevalence of diabetes did not differ between subjects with and without airflow obstruction. Furthermore, although body mass index decreased, no increase in the prevalence of diabetes was observed with the progression of airflow obstruction. The annual changes in forced expiration volume in 1 s (FEV1) did not differ depending on the presence or absence of diabetes in the study population.

Conclusion

There was no difference in the prevalence of diabetes between subjects with airflow obstruction and those without. As patients with COPD in Japan are thinner than in the West, diabetes may not be a common comorbidity in Japanese patients with COPD.  相似文献   
55.
Myocardial bridging increases the risk of coronary spasm   总被引:2,自引:0,他引:2  
BACKGROUND: Myocardial bridging (MB) has been associated with cardiac events. Whether coronary spasm is one factor contributing to those events is unknown. HYPOTHESIS: This study investigated whether the likelihood of coronary spasm is increased in patients with MB. METHODS: A spasm-provocation test was performed by infusing acetylcholine into the left coronary artery in 114 Japanese patients with chest pain. The test result was defined as positive when the diameter of the coronary artery was reduced by > or = 50% and ST-segment changes were documented. Myocardial bridging was defined as a > 15% reduction in coronary arterial diameter during systole after intracoronary injection of nitroglycerin. RESULTS: Myocardial bridging was identified in 41 patients (36%) and was located in the mid-segment of the left anterior descending coronary artery (LAD) in all patients. Patients with MB experienced coronary spasm more frequently than patients without MB (MB+: 73%; MB-: 40%, p = 0.0006). Furthermore, among patients with a positive spasm-provocation test, coronary spasm occurred more frequently in the mid-segment of the LAD in patients with MB than in those without MB (MB+: 73%; MB-: 45%, p = 0.0259). Multivariate regression analysis demonstrated that MB was a predictor of coronary spasm (odds ratio: 3.478, p = 0.0088). CONCLUSIONS: These results suggest that MB increases the risk of coronary spasm and that coronary spasm may be the proximate etiology of cardiac events associated with MB.  相似文献   
56.
We report on a Japanese boy with Noonan syndrome who had short stature, bilateral cryptorchidism, poor pubertal development, mild mental retardation, complex cardiac lesions consisting of hypertrophic cardiomyopathy, mitral valve stenosis and insufficiency, subvalvular aortic stenosis, and single coronary artery, and various dysmorphic features including hypertelorism, epicanthic folds, low set malrotated ears, high arched palate, micrognathia, webbed neck, low posterior hairline, shield chest, pectus excavatum, cubitus valgus, borderline short metatarsals, lymphedema, redundant skin, and nail dysplasia. Because of marked lymphedema in the bilateral lower legs, lymphatic scintigraphy was carried out at 13.3 years of age, indicating extreme lymphstasis in the lower extremities, severe lymphstasis in the forearm, the elbow, and the axillary regions, moderate lymphstasis around the ascending aorta, and mild lymphstasis in the bilateral lungs. The results, in conjunction with those suggested in Turner syndrome, imply that lymphatic hypoplasia/dysplasia and resultant distended lymphatics and lymphedema are relevant to the development of not only soft tissue and visceral anomalies but also skeletal anomalies in Noonan syndrome.  相似文献   
57.

Purpose

Thiamine is an essential component of glucose metabolism and energy production. The disulfide derivative, thiamine tetrahydrofurfuryl disulfide (TTFD), is better absorbed than readily-available water-soluble thiamine salts because it does not require the rate-limiting transport system required for thiamine absorption. However, the detailed pharmacokinetics of thiamine and TTFD under normal and pathological conditions have not yet been clarified. C-11-labeled thiamine and TTFD were recently synthesized by our group. In this study, to clarify the differences in pharmacokinetics and metabolism of these probes, a quantitative PET imaging study and radiometabolite analysis of C-11-labeled thiamine and TTFD were performed in the rat heart.

Procedures

Positron emission tomography (PET) imaging with [11C]thiamine and [11C]TTFD was performed in normal rats to determine the pharmacokinetics of these probes, and the radiometabolites of both probes from the blood and heart tissue were analyzed by thin-layer chromatography.

Results

Accumulation of [11C]TTFD was significantly higher than that of [11C]thiamine in the rat heart. Moreover, as a result of the radiometabolite analysis of heart tissue at 15 min after the injection of [11C]TTFD, thiamine pyrophosphate, which serves as a cofactor for the enzymes involved in glucose metabolism, was found as the major radiometabolite and at a significantly higher level than in the [11C]thiamine-injected group.

Conclusions

PET imaging techniques for visualizing the kinetics and metabolism of thiamine using [11C]thiamine and [11C]TTFD were developed in this study. Consequently, noninvasive PET imaging for the pathophysiology of thiamine-related cardiac function may provide novel information about heart failure and related disorders.
  相似文献   
58.

Purpose

To investigate temporal variations in dispatcher-assisted and bystander-initiated resuscitation efforts and their association with survival after bystander-witnessed out-of-hospital cardiac arrests (OHCAs).

Methods

We retrospectively analyzed the neurologically favorable 1-month survival and the parameters related to dispatcher assisted cardiopulmonary resuscitation (DA-CPR) and bystander CPR (BCPR) for 227,524 OHCA patients between 2007 and 2013 in Japan. DA-CPR sensitivity for OHCAs, bystander's compliance to DA-CPR assessed by the proportion of bystanders who follow DA-CPR, and performance of BCPR measured by the rate of bystander-initiated CPR in patients without DA-CPR were calculated as indices of resuscitation efforts.

Results

Performance of BCPR was only similar to temporal variations in the survival (correlation between hourly paired values, R2 = 0.263, P = 0.01): a lower survival rate (3.4% vs 4.2%) and performance of BCPR (23.1% vs 30.8%) during night-time (22:00–5:59) than during non-night-time. In subgroup analyses based on interaction tests, all three indices deteriorated during night-time when OHCAs were witnessed by non-family (adjusted odds ratio, 0.73–0.82), particularly in non-elderly patients. The rate of public access defibrillation for these OHCAs markedly decreased during night-time (adjusted odds ratio, 0.49) with delayed emergency calls and BCPR initiation. Multivariable logistic regression analyses revealed that the survival rate of non-family-witnessed OHCAs was 1.83-fold lower during night-time than during non-night-time.

Conclusions

Dispatcher-assisted and bystander-initiated resuscitation efforts are low during night-time in OHCAs witnessed by non-family. A divisional alert system to recruit well-trained individuals is needed in order to improve the outcomes of night-time OHCAs witnessed by non-family bystanders.  相似文献   
59.
60.
Journal of Gastroenterology - Following liver transplantation (LT), allograft liver failure can be developed by various causes and requires re-LT. Hence, this study aimed to clarify the...  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