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   860篇
  免费   56篇
  国内免费   41篇
耳鼻咽喉   6篇
儿科学   46篇
妇产科学   2篇
基础医学   160篇
口腔科学   6篇
临床医学   86篇
内科学   137篇
皮肤病学   1篇
神经病学   113篇
特种医学   72篇
外国民族医学   3篇
外科学   132篇
综合类   32篇
预防医学   28篇
眼科学   5篇
药学   63篇
中国医学   2篇
肿瘤学   63篇
  2024年   2篇
  2023年   7篇
  2022年   12篇
  2021年   30篇
  2020年   24篇
  2019年   19篇
  2018年   27篇
  2017年   11篇
  2016年   28篇
  2015年   35篇
  2014年   42篇
  2013年   48篇
  2012年   79篇
  2011年   70篇
  2010年   45篇
  2009年   39篇
  2008年   40篇
  2007年   66篇
  2006年   38篇
  2005年   51篇
  2004年   44篇
  2003年   35篇
  2002年   30篇
  2001年   24篇
  2000年   23篇
  1999年   11篇
  1998年   10篇
  1997年   8篇
  1996年   6篇
  1995年   8篇
  1994年   3篇
  1993年   2篇
  1992年   9篇
  1991年   4篇
  1990年   1篇
  1989年   5篇
  1988年   5篇
  1987年   2篇
  1986年   4篇
  1984年   1篇
  1982年   1篇
  1980年   1篇
  1979年   2篇
  1970年   1篇
  1967年   1篇
  1961年   1篇
  1928年   1篇
  1915年   1篇
排序方式: 共有957条查询结果,搜索用时 31 毫秒
871.
872.
Left ventricular thrombus typically occurs in patients with impaired left ventricular function such as aneurysm, dilated cardiomyopathy, or post-myocardial infarction. Untreated HIV infection is known to increase the risk of venous thromboembolism and cardiovascular disease. However, the pathophysiology remains uncertain; some studies have proposed chronic inflammation as the underlying etiology. Nonetheless, left ventricular thrombus is extremely rare among persons living with HIV with no known underlying cardiac disease. Herein, we report an unusual case of a 55-year-old homeless and heterosexual male with past medical history of HIV, who has mildly reduced left ventricular function and a nonmobile, medium size left ventricular thrombus. Patient was initially treated with therapeutic dose of enoxaparin, and subsequently developed acute embolic occlusion of right femoral artery that lead to an above knee amputation. To our knowledge, left ventricular thromboembolism complicated with acute embolic ischemia in persons living with HIV is extremely rare. The presenting case will definitely add to the current body of knowledge and will raise awareness among physicians, in recognizing the rare association between HIV and arterial thromboembolism.  相似文献   
873.

Objective

The role of community mental health centers (CMHCs) in Korea is quite different than that of these centers in Western countries due to nation-specific health care system characteristics. For example, CMHCs of Korea are expected to provide services for serious mental illness in addition to other services in response to community needs, such as internet addiction of adolescents. Consequently, it is important to determine service priorities of CMHCs and to define standard service performances in order to maximize their effectiveness with limited resources. The present study aimed to generate expert consensus on service priorities and to identify standard service performances of CMHCs in South Korea.

Methods

Forty-five mental health professionals participated as experts in a Delphi survey. We made a survey questionnaire based on Korean and international data and guidelines of some countries such as the UK and Australia. Experts answered the first and second round questionnaires and their answers were analyzed using frequency analysis.

Results

For the question about future directions of CMHCs, twenty-two experts (49%) answered that the growth of services for serious mental illness should be preferred to other areas. The service for chronic mental illness was thought to be the most important service area (27.1%) and, early psychosis (10.5%) is included, the services for serious mental illness should be regarded as the most important service area of Korean CMHCs. It is followed by child and adolescent services (13.2%) and mental health promotion services (10.8%). The relative importance of service performances on each service domain were given by answers of experts.

Conclusion

CMHCs in Korea should focus their priority on the management of serious mental illness. Service standardization by the relative importance of service performances on each service domain is needed.  相似文献   
874.
PURPOSE: To evaluate a technique for time-resolved breath-hold contrast material-enhanced three-dimensional magnetic resonance (MR) angiography of the abdomen. MATERIALS AND METHODS: In a prospective study, 43 patients underwent time-resolved MR angiography (acquisition time per data set, 7 seconds). The patients also underwent single-phase high-spatial-resolution MR angiography (acquisition time, 27 seconds) (n = 6), conventional angiography (n = 7), or both (n = 30). No bolus timing study was performed for time-resolved MR angiography. Image quality (presence of artifacts, ability to prevent venous overlap on arterial phase images, contrast enhancement) and demonstration of anatomic variants (renal arterial and venous variants, vena caval anomaly, visceral arterial variants) and vascular diseases were assessed. RESULTS: Time-resolved MR angiographic images were characterized by fewer and less severe artifacts, less overlap of enhancing veins, and better contrast enhancement than were single-phase MR angiographic images (P < .05). The mean sensitivity and specificity were 90% (nine of 10) and 100% (1 73 of 1 73), respectively, for detection of arterial anatomic variants and 93% (28 of 30) and 100% (324 of 325), respectively, for detection of disease. The technique also proved to be reliable for demonstration of venous disease. CONCLUSION: In comparison with current non-time-resolved MR angiographic techniques, time-resolved MR angiography is more robust and easier to perform and allows simultaneous evaluation of arterial and venous disease.  相似文献   
875.
PURPOSE: To review the literature on the diagnostic performance of multidetector computed tomographic (CT) angiography for assessment of symptomatic coronary artery disease, with conventional coronary angiography as the reference standard. MATERIALS AND METHODS: A PubMed and manual search of the literature published between January 1998 and May 2006 on use of multidetector CT angiography compared with coronary angiography in patients with symptomatic coronary artery disease was performed. Summary estimates of diagnostic odds ratio, sensitivity, and specificity were calculated. Random-effects models were used to compare the diagnostic performance of four-, 16-, and 64-detector CT angiographic units, and the proportion of nonassessable coronary arterial segments was evaluated. RESULTS: Fifty-four studies were included in the meta-analysis: 22 studies with four-detector CT angiography, 26 with 16-detector CT angiography, and six with 64-detector CT angiography. The pooled sensitivity and specificity for detecting a greater than 50% stenosis per segment were 0.93 (95% confidence interval [CI]: 0.88, 0.97) and 0.96 (95% CI: 0.96, 0.97) for 64-detector CT angiography, 0.83 (95% CI: 0.76, 0.90) and 0.96 (95% CI: 0.95, 0.97) for 16-detector CT angiography, and 0.84 (95% CI: 0.81, 0.88) and 0.93 (95% CI: 0.91, 0.95) for four-detector CT angiography, respectively. Results of regression analysis indicated that the diagnostic performance significantly improved with the newer generations of multidetector CT scanners (64- and 16-detector vs four-detector units), adjusted for exclusion of nonassessable segments, and contrast agent concentration used (P < .05). Simultaneously, the nonassessable proportion of segments significantly decreased with the newer generations of multidetector CT scanners, adjusted for heart rate, prevalence of significant disease, and mean age. CONCLUSION: With the newer generations of multidetector CT scanners, the diagnostic performance for the assessment of coronary artery disease has significantly improved, and the proportion of nonassessable segments has decreased.  相似文献   
876.
PURPOSE: We evaluated whether epigallocatechin gallate (EGCG), a main constituent of green tea polyphenols, could protect against cellular toxicity by oxalate and whether green tea supplementation attenuates the development of nephrolithiasis in an animal model. MATERIALS AND METHODS: Cells of the NRK-52E line were incubated with different concentrations of oxalate with and without EGCG, and toxicity and malondialdehyde assays were done to investigate the cytotoxic effect of oxalate and the anti-oxalate effect of EGCG.. In a second series of experiments, male Sprague-Dawley rats were divided into three groups. Group 1 animals (controls) were fed regular chow and drank water ad libitum; group 2 animals were fed chow containing 3% sodium oxalate with the administration of gentamicin (40 mg/kg) and drank water ad libitum; group 3 animals were fed the same diet as group 2 with gentamicin administration and drank only green tea. Rats were killed 4 weeks later after a 24-hour urine collection, and the kidneys were removed for morphologic examination. RESULTS: As oxalate concentrations increased, the number of surviving cells decreased, and the formation of free radicals increased. The administration of EGCG inhibited free-radical production induced by oxalate. Green tea supplementation decreased the excretion of urinary oxalate and the activities of urinary gammaglutamyltranspeptidase and N-acetylglucosaminidase. The number of crystals within kidneys in group 3 was significantly lower than in group 2. CONCLUSIONS: Green tea has an inhibitory effect on urinary stone formation, and the antioxidative action of EGCG is considered to be involved.  相似文献   
877.
Ku JH  Kim Y  Moon KC  Kim YS  Kim MS  Kim HH  Paick JS 《The Journal of urology》2006,176(3):1230-1235
PURPOSE: We determined whether hepatocyte growth factor gene transfer after partial bladder outlet obstruction would prove effective for decreasing transforming growth factor-beta expression and consequently decreasing collagen deposition in partially obstructed rat bladders. MATERIALS AND METHODS: Ten-week-old male Sprague-Dawley rats were divided into 3 groups of 10 each, including group 1--sham operation, group 2--bladder outlet obstruction for 4 weeks and group 3--hepatocyte growth factor gene transfer after bladder outlet obstruction. Two weeks after the onset of bladder outlet obstruction in group 3 hepatocyte growth factor-liposome complex (50 microg human hepatocyte growth factor cDNA) was injected into the smooth muscle of the rats. RESULTS: We noted no difference between groups 2 and 3 with regard to the ratio of bladder weight to body weight. The ratio in groups 2 and 3 was significantly higher than in group 1 (p = 0.043). The mean percent of collagen area +/- SE was 36.32% +/- 1.83%, 27.90% +/- 2.66% and 8.97% +/- 3.35% in groups 1 to 3, respectively (p <0.05). Relative hepatocyte growth factor and c-met mRNA and protein expression were higher in group 3 than in groups 1 and 2. However, the expression of transforming growth factor-beta1 mRNA and protein was higher in group 2 than in groups 1 and 3. CONCLUSIONS: These findings may imply a possible novel therapeutic strategy against bladder dysfunction arising in patients with bladder outlet obstruction.  相似文献   
878.

Purpose

The purpose of this study was to elucidate the prognostic factors for distal cholangiocarcinoma after curative resection, and to assess the significance of perineural invasion (PNI) and lymphovascular invasion (LVI) as prognostic factors.

Methods

A retrospective analysis of 91 patients who underwent radical surgery for distal cholangiocarcinoma between March 2004 and October 2011 was performed. We analyzed the survival rate and prognostic factors affecting the survival.

Results

The overall 1-, 3- and 5-year survival rates were 84.1, 49.7 and 38.9 %, respectively. In the univariate analysis, the prognostic factors influencing the survival were the histological differentiation, lymph node (LN) involvement and TNM stage. In the multivariate analysis, LN metastasis was the only independent prognostic factor. Although patients with PNI tended to show poorer survival, it was not a statistically significant factor (3- and 5-year OS; 62.0 and 54.6 % vs. 42.8 and 30.9 %, P = 0.166). In the patients with a total lymph node count (TLNC) of 11 or less, PNI was a significant prognostic factor; however, it was not a significant factor in the patients with a TLNC over 11. Overall, the LVI had no influence on the patient survival.

Conclusions

LN metastasis was the only significant prognostic factor after the curative resection of distal cholangiocarcinoma. In cases where adequate dissection was performed, it appeared that the PNI and LVI had no influence on the survival.  相似文献   
879.
Multidetector coronary computed tomography angiography (CTA) is a promising modality for widespread clinical application because of its noninvasive nature and high diagnostic accuracy as found in previous studies using 64 to 320 simultaneous detector rows. It is, however, limited in its ability to detect myocardial ischemia. In this article, we describe the design of the CORE320 study ("Combined coronary atherosclerosis and myocardial perfusion evaluation using 320 detector row computed tomography"). This prospective, multicenter, multinational study is unique in that it is designed to assess the diagnostic performance of combined 320-row CTA and myocardial CT perfusion imaging (CTP) in comparison with the combination of invasive coronary angiography and single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI). The trial is being performed at 16 medical centers located in 8 countries worldwide. CT has the potential to assess both anatomy and physiology in a single imaging session. The co-primary aim of the CORE320 study is to define the per-patient diagnostic accuracy of the combination of coronary CTA and myocardial CTP to detect physiologically significant coronary artery disease compared with (1) the combination of conventional coronary angiography and SPECT-MPI and (2) conventional coronary angiography alone. If successful, the technology could revolutionize the management of patients with symptomatic CAD.  相似文献   
880.
Background and PurposeWe aimed to determine whether the care process and outcomes in patients with acute stroke who received recanalization therapy changed during the outbreak of coronavirus disease 2019 (COVID-19) in South Korea.MethodsWe used data from a prospective multicenter reperfusion therapy registry to compare the care process—including the time from symptom onset to treatment, number of treated patients, and discharge disposition—and treatment outcomes between before and during the COVID-19 outbreak in South Korea.ResultsUpon the COVID-19 outbreak in South Korea, the number of patients receiving endovascular treatment to decrease temporarily but considerably. The use of emergency medical services by stroke patients increased from 91.5% before to 100.0% during the COVID-19 outbreak (p=0.025), as did the median time from symptom onset to hospital visit [median (interquartile range), 91.0 minutes (39.8–277.0) vs. 176.0 minutes (56.0–391.5), p=0.029]. Furthermore, more functionally dependent patients with disabilities were discharged home (59.5% vs. 26.1%, p=0.020) rather than staying in a regional or rehabilitation hospital. In contrast, there were no COVID-19-related changes in the times from the hospital visit to brain imaging and treatment or in the functional outcome, successful recanalization rate, or rate of symptomatic intracerebral hemorrhage.ConclusionsThese findings suggest that a prehospital delay occurred during the COVID-19 outbreak, and that patients with acute stroke might have been reluctant to visit and stay in hospitals. Our findings indicate that attention should be paid to prehospital care and the behavior of patients with acute stroke during the COVID-19 outbreak.  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