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   2646篇
  免费   135篇
  国内免费   16篇
耳鼻咽喉   7篇
儿科学   34篇
妇产科学   10篇
基础医学   342篇
口腔科学   190篇
临床医学   183篇
内科学   850篇
皮肤病学   12篇
神经病学   136篇
特种医学   54篇
外科学   492篇
综合类   12篇
预防医学   65篇
眼科学   51篇
药学   128篇
中国医学   1篇
肿瘤学   230篇
  2022年   20篇
  2021年   41篇
  2020年   21篇
  2019年   42篇
  2018年   55篇
  2017年   35篇
  2016年   46篇
  2015年   36篇
  2014年   57篇
  2013年   56篇
  2012年   115篇
  2011年   122篇
  2010年   68篇
  2009年   57篇
  2008年   107篇
  2007年   117篇
  2006年   120篇
  2005年   108篇
  2004年   108篇
  2003年   110篇
  2002年   107篇
  2001年   108篇
  2000年   124篇
  1999年   104篇
  1998年   31篇
  1997年   22篇
  1996年   27篇
  1995年   14篇
  1994年   19篇
  1993年   16篇
  1992年   77篇
  1991年   72篇
  1990年   55篇
  1989年   66篇
  1988年   41篇
  1987年   50篇
  1986年   55篇
  1985年   40篇
  1984年   43篇
  1983年   41篇
  1982年   21篇
  1981年   15篇
  1980年   15篇
  1979年   31篇
  1978年   18篇
  1977年   11篇
  1974年   11篇
  1970年   17篇
  1969年   17篇
  1968年   16篇
排序方式: 共有2797条查询结果,搜索用时 15 毫秒
41.
Aortoesophageal fistula (AEF) secondary to thoracic aneurysm is rare, and is usually fatal without prompt surgical intervention, with few survivors reported. Here we report a case of a 68-year-old woman late-presenting AEF successfully treated by extra-anatomic bypass grafting. Since she had already a mediastinal infection caused by AEF on admission, we performed extra-anatomic bypass grafting from the ascending aorta to the infrarenal aorta, and primary esophageal repair. The extra-anatomic bypass grafting was performed to avoid the risk to secondary graft infection and to decrease the total ishemic time induced by intraoperative aortic clamping, which is necessary when in-situ graft replacement is chosen. Although only 17 cases (including the present case) have been reported as long-term survivors, most have involved in-situ repair of the thoracic aneurysm. To our knowledge, the present case was only the second treated successfully by extra-anatomic bypass grafting. We recommend extra-anatomic bypass grafting for a case with severe infection and prolonged hypoperfusion insult caused by massive bleeding due to rupture in an aneurysm.  相似文献   
42.
AIM: Adrenomedullin (AM), a hypotensive and natriuretic peptide, consists of an amidated mature form (mAM) and an intermediate form in human plasma, of which only mAM exerts biological activity. Like atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP), plasma levels of mAM are reported to be significantly elevated in hemodialysis (HD) patients, suggesting that mAM may be stimulated partly by increased body fluid volume in a manner similar to the natriuretic peptides. Here, we examined the relationship between mAM levels and ANP or BNP levels and the effect of HD on plasma mAM in HD patients. PATIENTS AND METHODS: We measured plasma levels of mAM, total AM (tAM), ANP and BNP before and after HD in patients on long-term HD (n = 22, mean age 56.3 +/- 3.2 years) using radioimmunoassay. RESULTS: Baseline mAM (2.7 +/- 0.3 fmol/ml) and tAM (23.6 +/- 2.0 fmol/ml) were significantly higher in HD patients than in healthy subjects (1.1 +/- 0.2 fmol/ml, 9.0 +/- 2.1 fmol/ml, respectively). HD significantly reduced the levels to 1.2 +/- 0.2 fmol/ml and 13.8 +/- 1.4 fmol/ml, respectively, although tAM levels were still elevated compared to healthy subjects. Similar plasma ANP and BNP levels were obtained in HD patients. There were significant correlations between mAM and tAM levels before and after HD and between HD-induced changes in mAM and tAM levels. In the pre-HD state, levels of both mAM and tAM correlated significantly with BNP levels, but the correlation of BNP with mAM was closer than that with tAM. In contrast, no correlations were observed between the 2 forms of AM and ANP. Changes in mAM levels during HD also correlated significantly with BNP but not ANP levels, although the changes in tAM did not correlate with those of the 2 natriuretic peptides. CONCLUSION: Our results suggest that the secretion/metabolism of mAM may be regulated in a manner similar to that of BNP in HD patients.  相似文献   
43.
Radiographic evaluation of idiopathic clubfeet undergoing Ponseti treatment   总被引:1,自引:0,他引:1  
BACKGROUND: The Ponseti method for treatment of idiopathic clubfeet involves the use of serial casts, percutaneous Achilles tenotomy in most cases, and bracing with an abduction orthosis to prevent relapse. Although Ponseti recommended evaluation of the infant clubfoot strictly by palpation, many orthopaedic surgeons still rely on radiographs for decision-making during treatment. The aim of this study was to document with radiographs the effect of percutaneous Achilles tenotomy as described by Ponseti. METHODS: We conducted a study of idiopathic clubfeet treated, at two centers, with the Ponseti method, including percutaneous Achilles tenotomy. Cast treatment was started within three weeks after birth, and radiographs were made before and after the tenotomy. Lateral radiographs with the foot in maximal dorsiflexion at the ankle were made for all patients, and anteroposterior radiographs of the foot were made at one center. The lateral tibiocalcaneal angle, the anteroposterior talocalcaneal angle, and the lateral talocalcaneal angle were measured on the radiographs. Foot dorsiflexion at the ankle was evaluated clinically. The results from both centers were evaluated separately and in combination. RESULTS: Lateral dorsiflexion radiographs that showed the foot and ankle were evaluated for eighty-seven clubfeet, and anteroposterior radiographs that showed the foot were evaluated for sixty-five clubfeet. The mean improvement in the lateral tibiocalcaneal angle after the tenotomy was 16.9 degrees . The mean change in the anteroposterior talocalcaneal angle was 2.1 degrees , and the mean change in the lateral talocalcaneal angle change was 1.4 degrees . The mean increase in clinically measured dorsiflexion after the tenotomy (in sixty-five feet) was 15.1 degrees . Only the lateral tibiocalcaneal angle and dorsiflexion as measured clinically changed significantly after the Achilles tenotomy (p < 0.05). When the results at each center were analyzed separately, they were found to be nearly identical. CONCLUSIONS: The increase in the lateral tibiocalcaneal angle after Achilles tenotomy is essentially the same as the increase in ankle dorsiflexion seen on clinical examination. The anteroposterior and lateral talocalcaneal angles are not influenced significantly by the tenotomy. Radiographs confirmed that the additional dorsiflexion obtained from the percutaneous Achilles tenotomy is true dorsiflexion occurring in the ankle and hindfoot and not in the midfoot. LEVEL OF EVIDENCE: Therapeutic Level IV.  相似文献   
44.
Recent evidence suggests that single repeat metastasectomy may provide survival benefits for selected patients experiencing hepatic or pulmonary recurrences following initial hepatectomy for colorectal carcinoma metastases. The aim of this retrospective study was to clarify the efficacy of multiple repeat resections of intra- and extrahepatic recurrences following initial hepatectomy. A total of 100 patients underwent curative partial hepatectomy as the initial procedure for colorectal carcinoma metastases. Tumor relapse after initial hepatectomy was seen in 72 patients, of whom 28 underwent 45 repeat metastasectomies of various sites: 18 patients underwent a single repeat metastasectomy, and 10 underwent multiple repeat metastasectomies. The overall survival rate at 5 years after initial hepatectomy was 36.6%, while the 5-year survival rate after repeat metastasectomy in the 28 patients was 43.6%. The outcome of initial hepatectomy was comparable with that of repeat metastasectomy (p = 0.6924). Among the 28 patients undergoing repeat metastasectomy, the outcome of resection of intrahepatic recurrences in 11 patients was comparable with the outcome of resection of extrahepatic recurrences in 17 patients(p = 0.3926). The outcome of multiple repeat metastasectomies compared favorably with single repeat metastasectomy(p = 0.1803). Multivariate analysis(p < 0.0001) showed that repeat metastasectomy was the strongest prognostic factor. In conclusion, both single and multiple repeat resections of intra- and extrahepatic recurrences after initial hepatectomy are efficacious in colorectal carcinoma patients.Repeat resection should be considered for any resectable recurrences after hepatectomy.  相似文献   
45.
BACKGROUND: It has been suggested that, like ANP and BNP, high plasma levels of mature adrenomedullin (mAM) indirectly reflect the severity of heart failure or renal failure. However, the relationship between mAM levels and hemodynamics and cardiac function has not been examined in hemodialysis (HD) patients with coronary artery disease (CAD). The best marker, among mAM, ANP and BNP, for left-ventricular function in those patients is also unclear. PATIENTS AND METHODS: Plasma levels of mAM, total AM (tAM), ANP and BNP were determined before HD in chronic HD patients with CAD (group 1; n = 17) and were compared with those of HD patients without cardiac disease (group 2; n = 22). We examined their relationship to hemodynamics and cardiac function in group 1 using data obtained by cardiac catheterization. RESULTS: Plasma levels of ANP and BNP were significantly higher in group 1 than in group 2, but there was no significant difference in plasma levels of mAM and tAM between the two patient groups. Plasma levels of both mAM and tAM significantly correlated with right atrial pressure (RAP), and only plasma tAM levels correlated with pulmonary artery pressure (PAP) and pulmonary artery wedge pressure (PAWP). However, no correlations were found between levels of the two forms of AM and ejection fraction (EF). In contrast, plasma ANP and BNP levels significantly correlated with both PAP and PAWP, and also with EF, although they did not correlate with RAP. The correlation of PAP and PAWP with ANP and BNP levels was closer than that with tAM levels. The most significant correlation was between BNP levels and EF (r = -0.756, p < 0.0001). CONCLUSIONS: Our results suggest that the mAM level may be less useful than natriuretic peptide levels as a marker of cardiac function in HD patients with CAD, and that the BNP level might be the best indicator of left-ventricular function. In addition, cardiac disease such as CAD may have a minor impact on mAM levels compared to renal failure.  相似文献   
46.
The present study investigated intra‐articular injection of bone‐marrow‐derived mesenchymal stem cells (MSCs) combined with articulated joint distraction as treatment for osteochondral defects. Large osteochondral defects were created in the weight‐bearing area of the medial femoral condyle in rabbit knees. Four weeks after defect creation, rabbits were divided into six groups: control group, MSC group, distraction group, distraction + MSC group, temporary distraction group, and temporary distraction + MSC group. Groups with MSC received intra‐articular injection of MSCs. Groups with distraction underwent articulated distraction arthroplasty. Groups with temporary distraction discontinued the distraction after 4 weeks. The rabbits were euthanized at 4, 8, and 12 weeks after treatment except temporary distraction groups which were euthanized at only 12 weeks. Histological scores in the distraction + MSC group were significantly better than in the control, MSC group or distraction group at 4 and 8 weeks, but showed no further improvement. At 12 weeks, the temporary distraction + MSC group showed the best results, demonstrating hyaline cartilage repair with regeneration of the osteochondral junction. In conclusion, joint distraction with intra‐articular injection of MSCs promotes early cartilage repair, and compressive loading of the repair tissue after temporary distraction stimulates articular cartilage regeneration. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1466–1473, 2015.  相似文献   
47.
Shirouzu Y, Ohya Y, Suda H, Asonuma K, Inomata Y. Massive ascites after living donor liver transplantation with a right lobe graft larger than 0.8% of the recipient’s body weight.
Clin Transplant 2010: 24: 520–527.
© 2009 John Wiley & Sons A/S. Abstract: Background: There are only limited data on post‐transplant ascites unrelated to small‐sized grafts in living donor liver transplantation (LDLT). Methods: The subjects were 59 adult patients who had received right lobe LDLT with a graft weight‐to‐recipient weight ratio (GRWR) > 0.8%. Patients were divided into either Group 1 (n = 14, massive ascites, defined as the production of ascitic fluid > 1000 mL/d that lasted longer than 14 d after LDLT) or Group 2 (n = 45, no development of massive ascites). Patients were followed for a median period of 3.0 yr (range, 0.5–7.5 yr). Results: Group 1 had both higher Model for End‐Stage Liver Disease score and Child‐Pugh score than Group 2. Portal venous flow volume just after reperfusion was significantly greater in Group 1 than Group 2 (307.8 ± 268.8 vs. 176.2 ± 75.0 mL/min/100 g graft weight, respectively; p < 0.05). Post‐transplant infectious complications including ascites infection developed more frequently within the first post‐transplant month in Group 1. Massive ascites was significantly associated with early graft loss (p < 0.05). Conclusion: Post‐transplant massive ascites associated with portal over‐perfusion into the graft liver can develop in patients with a GRWR over 0.8%. Recipients with post‐transplant massive ascites require careful management to prevent infection.  相似文献   
48.
Complete rupture of a papillary muscle following acute myocardial infarction is a severe complication associate with acute left ventricular failure and pulmonary edema. Since the introduction of acute percutaneous transluminal coronary angioplasty (PTCA) in the management of acute myocardial infarction, the frequency of this complication has further decreased. We described a patient who had acute mitral regurgitation due to complete rupture of papillary muscle rupture after successful coronary intervention. Transesophageal echocardiography demonstrated severe mitral regurgitation and the ruptured papillary muscle. At operation, posteriol papillary muscle was found to be totally ruptured. Mitral valve replacement was performed. Postoperative course was uneventful, with 2 days of IABP and 5 days of ventilator support.  相似文献   
49.

Background

Salvage esophagectomy is potentially the only treatment available that can offer a chance of long-term survival when definitive chemoradiotherapy (CRT) fails to achieve local control for patients with esophageal squamous cell carcinoma (ESCC). However, salvage esophagectomy is a highly invasive procedure with various postoperative complications compared to planned esophagectomy after neoadjuvant chemoradiotherapy (CRT). We hypothesize that severe postoperative complications may affect not only surgical mortality but also tumor recurrence and long-term survival for patients with salvage esophagectomy after definitive CRT.

Methods

For the present study we reviewed the surgical procedures, postoperative complications, and the prognosis of 65 consecutive patients with thoracic ESCC who underwent the esophagectomy after neoadjuvant (neoadjuvant group: n = 40) or definitive (salvage group: n = 25) CRT.

Results

Most patients underwent right-transthoracic extended esophagectomy and reconstruction using gastric conduit by way of subcutaneous route with left cervical anastomosis. The incidence of postoperative pneumonia was found to be higher in the salvage group than in the neoadjuvant group. In both groups, the survival of patients with R0 resection was significantly better than those with R1/R2 resection. Moreover, in the salvage group, the postoperative survival rate of patients with pneumonia or bacteremia/sepsis was significantly lower than that for patients who did not suffer the same complications. In the neoadjuvant group, R0 resection was selected to be the only independent prognostic factor in univariate and multivariate analysis. In contrast, in the salvage group, R0 resection and bacteremia/sepsis remained significant and were independent of the other factors in multivariate analysis.

Conclusions

This study reveals that postoperative morbidity affects not only the perioperative mortality but also the long-term survival of patients with ESCC who undergo salvage esophagectomy after definitive CRT.  相似文献   
50.
Hepatic resection for colorectal metastases was performed for 188 patients. Overall survival rates after the first hepatectomy are 41.4% and 32.7% for 5 and 10 years, respectively. The survival rate of 116 cases with unilobar hepatic metastases (H1) is significantly higher than those of 48 cases with two to four bilobar metastases (H2) and 24 cases with more than four (H3), respectively. However, the differences between the survival rates from H1 with multiple metastases, H2, and H3 are not significant, even though the H3 group has no 10-year survivors. The 5-year survival rates after the second hepatectomy (30 patients) and the resection of the lung (26 patients) are 30.3% and 35.2%, respectively, in this series. In those patients, the 5-year survival rates from the first metastasectomy are 43.4% and 50.3%, respectively. There are 14 5-year survivors with multiple metastases and 8 of those patients underwent multiple surgeries. There are 13 patients with three or more repeat resections of the liver and/or lung. The 5-year survival rates of the patients from the first and third metastasectomy are 53.9% and 22.5%, respectively. Repeat operations for the liver and the lung contribute to the improving prognosis. Presented at the Forty-Sixth Annual Meeting of The Society for Surgery of the Alimentary Tract, Chicago, Illinois, May 14–18, 2005 (poster presentation).  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