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   1176篇
  免费   62篇
  国内免费   7篇
耳鼻咽喉   17篇
儿科学   12篇
妇产科学   42篇
基础医学   81篇
口腔科学   31篇
临床医学   80篇
内科学   261篇
皮肤病学   12篇
神经病学   71篇
特种医学   31篇
外科学   416篇
综合类   5篇
预防医学   47篇
眼科学   30篇
药学   29篇
中国医学   1篇
肿瘤学   79篇
  2024年   1篇
  2023年   21篇
  2022年   31篇
  2021年   61篇
  2020年   38篇
  2019年   37篇
  2018年   49篇
  2017年   37篇
  2016年   47篇
  2015年   54篇
  2014年   93篇
  2013年   86篇
  2012年   93篇
  2011年   111篇
  2010年   63篇
  2009年   61篇
  2008年   62篇
  2007年   68篇
  2006年   28篇
  2005年   33篇
  2004年   27篇
  2003年   18篇
  2002年   21篇
  2001年   14篇
  2000年   15篇
  1999年   17篇
  1998年   3篇
  1997年   1篇
  1996年   1篇
  1994年   1篇
  1993年   4篇
  1992年   8篇
  1991年   6篇
  1990年   5篇
  1989年   2篇
  1988年   6篇
  1987年   3篇
  1986年   1篇
  1985年   2篇
  1984年   3篇
  1983年   1篇
  1981年   1篇
  1980年   2篇
  1979年   5篇
  1978年   1篇
  1976年   1篇
  1970年   1篇
  1966年   1篇
排序方式: 共有1245条查询结果,搜索用时 46 毫秒
71.
Chronic obstructive pulmonary disease (COPD) is characterized by expiratory airflow limitation, but current diagnostic criteria only consider flow till the first second and are therefore strongly debated. We aimed to develop a data-based individualized model for flow decline and to explore the relationship between model parameters and COPD presence. A second-order transfer function model was chosen and the model parameters (namely the two poles and the steady state gain (SSG)) from 474 individuals were correlated with COPD presence. The capability of the model to predict disease presence was explored using 5 machine learning classifiers and tenfold cross-validation. Median (95 % CI) poles in subjects without disease were 0.9868 (0.9858–0.9878) and 0.9333 (0.9256–0.9395), compared with 0.9929 (0.9925–0.9933) and 0.9082 (0.9004–0.9140) in subjects with COPD (p < 0.001 for both poles). A significant difference was also found when analysing the SSG, being lower in COPD group 3.8 (3.5–4.2) compared with 8.2 (7.8–8.7) in subjects without (p < 0.0001). A combination of all three parameters in a support vector machines corresponded with highest sensitivity of 85 %, specificity of 98.1 % and accuracy of 88.2 % to COPD diagnosis. The forced expiration of COPD can be modelled by a second-order system which parameters identify most COPD cases. Our approach offers an additional tool in case FEV1/FVC ratio-based diagnosis is doubted.  相似文献   
72.
Langerhans cell histiocytosis is a rare neoplastic proliferative disorder of the Langerhans cells. The clinical course is variable, ranging from a low symptomatic single bone lesion to fatal multiple organ involvement. Rarely, the sternum can be the first and single location of the disease. We report on a 12‐year‐old boy who presented with an aggressive lytic lesion of the proximal sternum associated with local pain and afternoon fever. Histopathological analysis of the closed biopsy specimen indicated eosinophilic granuloma of bone/Langerhans cell histiocytosis. Soon after the biopsy procedure the pain and fever subsided. Computed tomography at 2 months showed healing of the lytic lesion. The patient received no other type of treatment. At 2 year follow up he was symptom and disease free.  相似文献   
73.
Background and Objective  Prostate cancer (PCa) is a severe public health issue and the most common cancer worldwide in men. Early diagnosis can lead to early treatment and long-term survival. The addition of the multiparametric magnetic resonance imaging in combination with ultrasound (mpMRI-U/S fusion) biopsy to the existing diagnostic tools improved prostate cancer detection. Use of both tools gradually increases in every day urological practice. Furthermore, advances in the area of information technology and artificial intelligence have led to the development of software platforms able to support clinical diagnosis and decision-making using patient data from personalized medicine. Methods  We investigated the current aspects of implementation, architecture, and design of a health care information system able to handle and store a large number of clinical examination data along with medical images, and produce a risk calculator in a seamless and secure manner complying with data security/accuracy and personal data protection directives and standards simultaneously. Furthermore, we took into account interoperability support and connectivity to legacy and other information management systems. The platform was implemented using open source, modern frameworks, and development tools. Results  The application showed that software platforms supporting patient follow-up monitoring can be effective, productive, and of extreme value, while at the same time, aiding toward the betterment medicine clinical workflows. Furthermore, it removes access barriers and restrictions to specialized care, especially for rural areas, providing the exchange of medical images and patient data, among hospitals and physicians. Conclusion  This platform handles data to estimate the risk of prostate cancer detection using current state-of-the-art in eHealth systems and services while fusing emerging multidisciplinary and intersectoral approaches. This work offers the research community an open architecture framework that encourages the broader adoption of more robust and comprehensive systems in standard clinical practice.  相似文献   
74.
BACKGROUND: CT has proved to be helpful in patients with acute pancreatitis for differentiating between mild and severe forms. Followup of acute pancreatitis with CT has been advocated but rarely studied. The aim of this study was to determine if late CT performed at day 7 might be helpful in establishing the prognosis or the type of complications, and to select a subgroup of patients in whom CT could be beneficial. STUDY DESIGN: Contrast-enhanced CT was performed at the admission day and 7 days after admission in 102 patients admitted for acute pancreatitis. The extent of pancreatic inflammation was classified according to Balthazar grade, and intrapancreatic necrosis on these examinations was prospectively assessed and compared with clinical and biologic data and with patient outcomes. RESULTS: Among 102 patients, complications developed in 24 (23%). Complications developed in only 8% of patients with Ranson score <2, making routine early CT unnecessary. For the patients with Ranson score <2 and Balthazar grades A and B at day 1 CT, late CT seemed to be useless. Complication was suspected by clinical and biologic tests before day 7 in 22 of 24 complicated patients (92%), suggesting that CT could be proposed only in cases of clinical or biologic deterioration. Late CT was correlated with a complicated course in patients with Balthazar grades D and E or intrapancreatic necrosis >50%. Late CT was predictive of complications in cases of intrapancreatic necrosis enlarging since the first examination. CONCLUSIONS: Our study showed that in acute pancreatitis: 1) there is little justification for systematic early CT, especially in patients with Ranson score <2, and 2) late CT does not need to be performed routinely, but only in cases of clinical or biologic worsening.  相似文献   
75.
Ancient schwannomas are benign long standing schwannomas of the neural sheaths. Histological findings are these seen as in conventional schwannomas, but ancient schwannomas additionally demonstrate cystic hemorrhagic changes and degenerative nuclei with pleomorphism and hyperchromasia. Due to the nuclear atypia, and cystic degeneration, ancient schwannomas might be confused with malignant tumors on histology and imaging, leading to a radical surgical approach. The median nerve is rarely affected. We present a rare case of an ancient schwannoma involving the median nerve at the mid humerus. The tumor slowly grew up within ten years and become symptomatic with local pain, mild numbness in the distribution of the median nerve in the palm and Tinel’s test. The tumor was successfully removed by separating it from the nerve fascicles to negative margins. Post-operatively local symptoms relieved but minor sensory loss in the median nerve distribution in the palm was noticed which improved in the following six months. Ancient schwannomas can be misdiagnosed as sarcomas due to specific imaging and histologic findings. Patients’ physical examination, history and fine radiologic and pathology features should be cautiously interpreted in order to achieve correct diagnosis and avoid unnecessary wide tumor excisions.  相似文献   
76.
77.
78.
79.
80.
The aim of this study was to determine by univariate and multivariate analyses the factors associated with clinically significant anastomotic leakage (AL) after large bowel resection. From 1990 to 1997 a series of 707 patients underwent colonic or rectal resection (without a stoma). Patients were divided into two groups: those with clinical anastomotic leakage (group 1) and those without it (group 2). AL occurred in 43 of 707 patients (6%). The overall mortality was 2.2% and was significantly higher in patients with AL than in those without: 5 of 43 (12%) versus 11 of 664 (1.6%), p <0.001. Univariate analysis showed 15 variables associated with the risk of AL: previous abdominal or pelvic irradiation (p = 0.02), American Society of Anesthesiologists (ASA) score > 2 (p = 0.04), leukocytosis (p = 0.02), renal failure (p = 0.03), steroid treatment (p = 0.01), duration of operation (p = 0.001), intraoperative septic conditions (p = 0.006), total colectomy (p = 0.009), transverse colectomy (p = 0.02), difficulties encountered during anastomosis (p = 0.001), ileorectal anastomosis (p = 0.02), colocolic anastomosis (p = 0.01), abdominal drainage (p = 0.05), and blood transfusion intraoperatively (p = 0.006) and postoperatively (p = 0.001). Multivariate analysis showed that only preoperative leukocytosis (p = 0.04), intraoperative septic conditions (p = 0.001), difficulties encountered during anastomosis (p = 0.007), colocolic anastomosis (p = 0.004), and postoperative blood transfusion (p = 0.0007) were independent factors associated with AL. The risk of AL increased from a range of 12% to 30% if one risk factor was present, to 38% with two factors, to 50% with three factors. After colorectal resection and intraperitoneal anastomosis, a temporary protective stoma is proposed in selected patients with high risk factors for AL, as observed in our study.  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