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   39620篇
  免费   2749篇
  国内免费   126篇
耳鼻咽喉   369篇
儿科学   974篇
妇产科学   940篇
基础医学   5139篇
口腔科学   657篇
临床医学   3860篇
内科学   7631篇
皮肤病学   588篇
神经病学   4132篇
特种医学   1281篇
外科学   6515篇
综合类   484篇
现状与发展   1篇
一般理论   36篇
预防医学   3282篇
眼科学   1011篇
药学   2708篇
中国医学   114篇
肿瘤学   2773篇
  2023年   223篇
  2022年   400篇
  2021年   880篇
  2020年   543篇
  2019年   798篇
  2018年   1014篇
  2017年   720篇
  2016年   724篇
  2015年   860篇
  2014年   1328篇
  2013年   1724篇
  2012年   2800篇
  2011年   2925篇
  2010年   1645篇
  2009年   1493篇
  2008年   2660篇
  2007年   2849篇
  2006年   2682篇
  2005年   2622篇
  2004年   2506篇
  2003年   2374篇
  2002年   2176篇
  2001年   390篇
  2000年   348篇
  1999年   406篇
  1998年   448篇
  1997年   395篇
  1996年   380篇
  1995年   317篇
  1994年   299篇
  1993年   266篇
  1992年   234篇
  1991年   206篇
  1990年   163篇
  1989年   148篇
  1988年   168篇
  1987年   157篇
  1986年   141篇
  1985年   144篇
  1984年   148篇
  1983年   157篇
  1982年   195篇
  1981年   173篇
  1980年   147篇
  1979年   88篇
  1978年   114篇
  1977年   117篇
  1976年   87篇
  1975年   89篇
  1974年   75篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
72.
73.
Background. Heparin bonding of the cardiopulmonary bypass (CPB) circuit may be associated with a reduced inflammatory response and improved clinical outcome. The relative contribution of a heparin-bonded oxygenator (ie, >80% of circuit surface area) to these effects was assessed in a group of pediatric patients.

Methods. Twenty-one pediatric patients undergoing CPB operations were assigned randomly to receive either a heparin-bonded oxygenator (group H, n = 11) or a nonbonded oxygenator (group C, n = 10) in otherwise nonbonded circuits. The two groups were similar in pathology, age, weight, CPB time, and cross-clamp time. Plasma levels of the cytokines tumor necrosis factor-, interleukin-6, and interleukin-8, as well as terminal complement complex, neutrophils, and elastase, were analyzed before, during, and after CPB.

Results. Significant levels of tumor necrosis factor- were not detected in either group. Plasma levels of all other markers increased during and after CPB compared with baseline. Plasma levels of interleukin-6 peaked in both groups 2 hours after the administration of protamine but remained significantly higher in group C 24 hours after operation. Plasma concentrations of interleukin-8 peaked at similar levels in both groups 30 minutes after protamine administration and returned to baseline thereafter. Levels of terminal complement complex and elastase peaked in both groups 30 minutes after protamine administration. Plasma levels of terminal complement complex were significantly higher at the end of CPB and after protamine administration in group C. Elastase levels were significantly higher 2 and 24 hours after CPB in group C. The ventilation time of patients in group H was significantly lower than that of patients in group C: 10 (range, 3 to 24) versus 22 (range, 7 to 24) hours, respectively (p < 0.01).

Conclusions. The present study confirms the proinflammatory nature of pediatric operations and demonstrates a lessened systemic inflammatory response with the use of heparin-bonded oxygenators. This is achieved without bonding of the entire circuit, which could have significant cost-benefit implications by negating the need for custom-built heparin-bonded circuitry.  相似文献   

74.
Background : Osseous cranial base tumours in children present as a diverse collection of both benign and malignant pathologies. Concerns raised by the difficulty in accurate diagnosis and local recurrence of benign lesions and by the long-term sequelae of radiotherapy for malignant cranial tumours (marked local growth disturbances, pituitary dysfunction, visual disturbances, late new tumour induction) prompted an evaluation of surgical resection of cranial base tumours in children, with specific regard to safety, efficacy and aesthetic result. Methods : A retrospective review was performed of 10 consecutive children presenting with tumours either arising from or eroding into bone of the cranial base who were managed by surgical resection in a 10-year period from 1986 to 1996. The patients demonstrated a great variation in both presentation and pathology. All underwent surgical resection of tumour with reconstruction where indicated. Results : There were no postoperative complications or mortality. All patients remained clinically free of disease at follow-up, which ranged from 17 months to 9 years (mean 6 years and 4 months). Conclusion : The aggressive surgical resection and craniofacial reconstruction of cranial base tumours in the paediatric population offers a safe and efficacious mode of treatment that obviates problems of diagnosis and local recurrence for benign lesions and of the long-term sequelae of radiotherapy for malignant lesions.  相似文献   
75.
Thoracoscopic Retrieval of Foreign Bodies After Penetrating Chest Trauma   总被引:1,自引:0,他引:1  
Video-assisted thoracic surgery or thoracoscopy has proved to be valuable in many settings in thoracic surgery. The use of video-assisted thoracic surgery in trauma has been limited, especially with respect to penetrating trauma. We report the use of thoracoscopy to remove intrathoracic fragments of glass and avert the need for a thoracotomy.  相似文献   
76.
BACKGROUND: High-dose chemotherapy followed by autologous blood stem cell transplantation induces remission of plasma cell dyscrasia in patients with AL amyloidosis. The impact of this treatment on the glomerular amyloid mass is still unknown. METHODS: In the present study, the quantity of the renal amyloid mass before and more than 3 years after high-dose melphalan treatment and autologous blood stem cell transplantation was assessed in two patients. At the time of the second renal biopsy, both patients were in complete remission without detectable serum and urinary monoclonal IgA-lambda and a normal percentage of plasma cells in the bone marrow. RESULTS: In both patients with biopsy-proven AL amyloidosis, urinary protein excretion decreased from 7 g/24 h to <2 g/24 h more than 3 years after autologous blood stem cell transplantation. In contrast, glomerular amyloid deposits persisted, as shown in the second biopsy. CONCLUSION: Despite complete remission of the plasma cell dyscrasia and improvement of glomerular permeability, the amount of glomerular amyloid mass did not regress.  相似文献   
77.
78.
To determine the utility of the lateral view of the chest in emergency department patients, records of all patients who had had 2-view chest x-rays ordered in the emergency department were reviewed retrospectively. A study radiologist recorded a reading of the posteroanterior (PA) radiograph alone. The lateral radiograph was then provided, along with the PA view, and a second reading was recorded. A comparison was then made between the first and second readings.A total of 417 sets of x-rays were included. The PA view alone successfully diagnosed or suspected 92% of pulmonary nodules, 95% of effusions, 97% of cases of emphysema, 98% of pneumonias, and 100% of cases of cardiomegaly, pulmonary edema, interstitial pulmonary disease, and atelectasis.In the emergency department patient population, lateral views of the chest have minimal diagnostic yield and therefore may be used selectively to safely decrease the amount of breast radiation exposure to young women.  相似文献   
79.
80.
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