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   15294篇
  免费   958篇
  国内免费   88篇
耳鼻咽喉   158篇
儿科学   286篇
妇产科学   258篇
基础医学   2057篇
口腔科学   154篇
临床医学   1355篇
内科学   3681篇
皮肤病学   274篇
神经病学   1617篇
特种医学   708篇
外科学   2679篇
综合类   32篇
一般理论   2篇
预防医学   676篇
眼科学   138篇
药学   1026篇
中国医学   19篇
肿瘤学   1220篇
  2024年   12篇
  2023年   108篇
  2022年   172篇
  2021年   471篇
  2020年   224篇
  2019年   456篇
  2018年   541篇
  2017年   357篇
  2016年   361篇
  2015年   444篇
  2014年   692篇
  2013年   803篇
  2012年   1283篇
  2011年   1317篇
  2010年   733篇
  2009年   707篇
  2008年   1065篇
  2007年   1010篇
  2006年   1022篇
  2005年   903篇
  2004年   869篇
  2003年   712篇
  2002年   692篇
  2001年   135篇
  2000年   95篇
  1999年   124篇
  1998年   124篇
  1997年   111篇
  1996年   84篇
  1995年   76篇
  1994年   68篇
  1993年   46篇
  1992年   64篇
  1991年   45篇
  1990年   38篇
  1989年   45篇
  1988年   47篇
  1987年   35篇
  1986年   28篇
  1985年   23篇
  1984年   18篇
  1983年   18篇
  1982年   15篇
  1975年   14篇
  1974年   14篇
  1972年   13篇
  1971年   14篇
  1970年   18篇
  1969年   15篇
  1968年   8篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Introduction  Hemangiopericytoma is an uncommon soft tissue vascular neoplasm. Intraperitoneal hemangiopericytomas such as primary or secondary liver location have been exceptionally described. Its natural history is mostly benign, but recurrences may occur and determining if these late-discovered tumors are distant metastases or synchronous slow and silent-growing locations is sometimes challenging. The histopathological diagnosis and definition of hemangiopericytoma is based on its distinction with solitary fibrous tumors. Liver resection to treat liver hemangiopericytoma seems to be supported by various published experiences. Case presentation  We herein report the first case of liver metastases from a subcutaneous temporal hemangiopericytoma. The patient was treated by a liver resection. CD34 Immunostaining was negative, but strong expression of Bcl2 and CD99 was found in the neoplastic cells. After 1 year of follow-up, the patient is alive without recurrence. Conclusion  To date, published data, including the case herein reported, support the need for a prolonged follow-up and the role of liver resection to treat liver metastases of hemangiopericytomas. Complete resection of all gross disease appears to be the most significant prognostic factor.  相似文献   
102.
BackgroundAntibodies to cyclic citrullinated peptide (anti-CCP) and IgM rheumatoid factor (IgM-RF) are well-established serological markers for rheumatoid arthritis (RA). Lupus-like disease with antinuclear antibodies (ANA) has been reported during TNFα antagonist therapy. Our objectives were to investigate the effect of infliximab therapy on these three autoantibodies in patients with established RA and to look for correlations linking IgM-RF and anti-CCP titres to a treatment response (defined as a good or moderate EULAR response) after 48 weeks of infliximab therapy.MethodsThirty-six patients with long-standing RA not responding to disease-modifying anti-rheumatic drugs (DMARDs) received intravenous infliximab (starting dose: 3 mg/kg) at 0, 2, and 6 weeks then at 8-week intervals, in combination with a DMARD. At baseline, week 24, and week 48, C-reactive protein (CRP) and the erythrocyte sedimentation rate (ESR) were determined and the disease activity score (DAS28) was calculated. Serum samples collected at the same time points were used to measure anti-CCP (commercial second-generation ELISA), IgM-RF (quantitative nephelometric assay), and ANA (indirect immunofluorescence in HEp2 cells). Correlations linking baseline autoantibody titres to changes in autoantibody levels were examined.ResultsAt baseline, tests were positive for anti-CCP in 31/36 (94.6%) patients, IgM-RF in 29/36 (80.5%) patients, and ANA in 16/36 (44%) patients. IgM-RF titres decreased significantly (p < 0.001), whereas anti-CCP showed little change (p = 0.053). ANA titres increased significantly (p < 0.001). The treatment response was not associated with changes in anti-CCP or IgM-RF titres during infliximab therapy (OR for a response in patients with a 50% anti-CCP decrease, 0.77 [95%CI, 0.16–3.58]; OR for a response in patients with a 50% IgM-RF decrease, 0.82 [95%CI, 0.16–4.13]).ConclusionsDuring infliximab therapy used to treat established RA, IgM-RF titres showed larger decreases than anti-CCP titres. Changes in IgM-RF and anti-CCP failed to correlate with the 48-week treatment response.  相似文献   
103.
104.
105.
Peri-anastomotic graft stenosis is a possible complication of coronary artery bypass graft operations. Early failure of myocardial revascularization may result from graft stenosis with inherent difficulties in perioperative diagnosis and subsequent management. We report the case of a 58-year-old man who experienced early preanastomotic left internal thoracic artery bypass stenosis that progressively resolved during a 2-year period without reoperation or interventional angioplasty. Although the mechanisms underlying graft stenosis remain unclear, this case emphasizes the role of repeated coronary angiography in the choice of treatment.  相似文献   
106.
Pericardial puncture is the percutaneous insertion of a needle into the pericardial space to drain a pathological pericardial effusion. The challenge for the operating surgeon is to reach percutaneously a target zone in the vicinity of the mobile heart, in a soft-tissue environment. The surgeon's ability to accomplish this depends on his own mental picture of the effusion. CASPER is a navigation software using an optical localizer which assists the surgeon by enhancing the representation of the effusion and guiding the needle's progress. Using a localized and calibrated echographic probe, the surgeon acquires a set of images in the region of interest. This zone is then manually segmented on each image, a common zone is computed, and the surgeon defines a trajectory for the needle. During the puncture procedure, the surgeon follows the position of the localized needle on a computer monitor. After initial validation on an experimental phantom, a feasibility study was performed using canine and porcine models. The optical localization device was changed from an Optotrak to a Polaris device for easier use in the clinical setting. Prior to clinical application, various tests were performed concerning the mobility of the thoracic cage, the reproducibility of the thoracic position over several apneas, and the stability of anatomic structures relative to the thoracic cage. Finally, a first clinical application was successfully performed using this system. The present paper reports on these last two stages.  相似文献   
107.
Background  Patients undergoing bariatric surgery with a gastric bypass lose about 66% of excess weight. Although this procedure induces weight loss, it is unknown whether it leads to protein malnutrition, which is studied here. Methods  One hundred ten obese patients (body mass index, 47.9 ± 8.6 kg/m2) undergoing gastric bypass had a measurement of plasma albumin and transthyretin (formerly prealbumin) and a calculation of nutritional risk index (NRI) before and throughout the 2 years following the surgery. Results  All but five patients lost more than 15% of initial weight; the mean loss of excess weight was 65.2 ± 26.4% at 2 years. Plasma concentrations of albumin and transthyretin decreased after surgery, but while albumin returned to initial values after 12 months, transthyretin remained low. Only one patient had an albumin below 30 g/l; another one had a transthyretin lower than 110 mg/l. All NRI scores were lower than 83.5 (62 ± 5, ranging 44–70), qualifying patients for severe malnutrition. Conclusion  Malnutrition is difficult to diagnose in obese patients undergoing surgery. The large weight loss is most often not associated with protein malnutrition. Whether gastric bypass induces protein malnutrition remains to be established.  相似文献   
108.
Osteoporosis treatments need to combine an unequivocally demonstrated reduction of fractures, at various skeletal sites, long-term safety, and a user-friendly profile that optimizes therapeutic adherence. Strontium ranelate is the first compound to simultaneously decrease bone resorption and stimulate bone formation. Its anti-fracture efficacy at various skeletal sites has been established for as long as 5 years through studies of the highest methodological standards. Increases in bone mineral density observed after 1 year of treatment are predictive of the long-term fracture efficacy, suggesting for the first time in osteoporosis that bone densitometry can be used as a monitoring tool. Due to a positive risk/benefit ratio, strontium ranelate is now considered as a first-line treatment in the management of osteoporosis.  相似文献   
109.
BACKGROUND: Cardiac myxoma is generally considered to be a surgical emergency. However, as a result of progress in echocardiography and the increasing age of the patients presenting with this disease, the clinical presentation has changed and the management of cardiac myxoma now needs to be reviewed. METHODS: Between 1978 and 2001, 40 patients (16 men and 24 women) between the ages of 6 months and 82 years (mean age, 55.6 years) were operated on for cardiac myxoma. Signs of heart failure with pulmonary congestion (22%) or pulmonary embolism (20%) indicated a high-risk emergency situation in some cases, whereas, in other cases (58%), the patient's condition was stable and the clinical presentation was less worrying. However, the tumor was always removed within 24 hours of admission. Most cases of cardiac myxoma observed over the last decade correspond to stable forms, as echocardiography has revealed smaller tumors in generally elderly patients. RESULTS: The postoperative mortality was 7.5% (3 patients). No patients were lost to follow-up, and the mean follow-up was 13.6 years. One patient was reoperated for recurrence 3 years postoperatively. Five patients required further cardiac surgery: three mitral valve replacements, one coronary artery bypass graft, and one angioplasty. The 15-year survival rate was 69%. CONCLUSIONS: Myxoma tends to be observed in a more elderly and higher risk population, often at an early stage. The classic approach of emergency surgery is not always appropriate in these stable forms, allowing more thorough preoperative assessment of these patients.  相似文献   
110.
Spontaneous hemothorax is a rare and life threatening complication of neurofibromatosis. Two types of vascular involvement have been described: (a) stenotic or aneurysmal alterations in large vessels such as the aorta and its branches; and (b) dysplastic features in smaller vessels. Thoracotomy and surgical ligation of the bleeding vessels is primarily indicated in the presence of active bleeding with associated hemodynamic compromise. A more conservative approach with endovascular embolization or non-operative management have also been reported in case of hemodynamic stability. We present a rare case of spontaneous hemothorax treated conservatively in a patient with von Recklinghausen's disease.  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