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   4701篇
  免费   272篇
  国内免费   52篇
耳鼻咽喉   66篇
儿科学   75篇
妇产科学   73篇
基础医学   578篇
口腔科学   78篇
临床医学   408篇
内科学   1398篇
皮肤病学   95篇
神经病学   396篇
特种医学   183篇
外科学   707篇
综合类   25篇
一般理论   5篇
预防医学   193篇
眼科学   58篇
药学   264篇
中国医学   9篇
肿瘤学   414篇
  2024年   10篇
  2023年   50篇
  2022年   93篇
  2021年   177篇
  2020年   98篇
  2019年   147篇
  2018年   161篇
  2017年   121篇
  2016年   146篇
  2015年   154篇
  2014年   185篇
  2013年   275篇
  2012年   443篇
  2011年   386篇
  2010年   219篇
  2009年   174篇
  2008年   317篇
  2007年   272篇
  2006年   262篇
  2005年   265篇
  2004年   233篇
  2003年   197篇
  2002年   185篇
  2001年   48篇
  2000年   39篇
  1999年   43篇
  1998年   35篇
  1997年   19篇
  1996年   12篇
  1995年   12篇
  1994年   20篇
  1993年   11篇
  1992年   15篇
  1991年   16篇
  1990年   20篇
  1989年   14篇
  1988年   19篇
  1987年   16篇
  1986年   20篇
  1985年   16篇
  1984年   12篇
  1983年   10篇
  1982年   6篇
  1981年   7篇
  1980年   7篇
  1979年   16篇
  1977年   4篇
  1976年   2篇
  1974年   3篇
  1971年   3篇
排序方式: 共有5025条查询结果,搜索用时 20 毫秒
31.
32.
A 70-year-old man with a painful vertebral metastasis was treated with combined percutaneous cryoablation and vertebroplasty therapy (CVT) in one session. The patient was suffering from diffuse visceral metastasized cholangiocarcinoma. After several weeks of back pain, magnetic resonance imaging documented a single L2 bone metastasis. In consultation with the oncologists, palliative combined CVT was administered with the aim of obtaining pain relief and bone stabilization. In our experience this combined treatment is safe and effective for immediate pain relief in painful bone metastases when other standard palliative treatments have failed.  相似文献   
33.
PURPOSE: We characterize the consequences of androgen deprivation therapy on body composition in elderly men. MATERIALS AND METHODS: Using a dual energy x-ray absorptiometry instrument, we determined the changes in bone mineral density, bone mineral content, fat body mass and lean body mass in 35 patients with prostate cancer without bone metastases who received luteinizing hormone releasing hormone analogue for 12 months. RESULTS: At baseline conditions 46% of cases were classified as osteopenic and 14% as osteoporotic at the lumbar spine and 40% were osteopenic and 4% osteoporotic at the hip. Androgen deprivation significantly decreased bone mineral density either at the lumbar spine (mean gm./cm.2 [SD] 1.00 [0.194], 0.986 [0.172] and 0.977 [0.182] at baseline, and 6 and 12 months, respectively, p <0.002) or the hip (0.929 [0.136], 0.926 [0.144] and 0.923 [0.138], p <0.03). A more than 2% decrease in bone mineral density was found at the lumbar spine in 19 men (54.3%) and at the hip in 15 (42.9%). Bone mineral content paralleled the bone mineral density pattern. Lean body mass decreased (mean gm. [SD] 50,287 [6,656], 49,296 [6,554] and 49,327 [6,345], p <0.003), whereas fat body mass consistently increased (18,115 [6,209], 20,724 [6,029] and 21,604 [5,923] p <0.001). CONCLUSIONS: Serial bone densitometry evaluation during androgen deprivation therapy may allow the detection of patients with prostate cancer at risk for osteoporotic fractures, that is those with osteopenia or osteoporosis at baseline and fast bone loss. The change in body composition may predispose patients to accidental falls, thus increasing the risk of bone fracture.  相似文献   
34.
Background Timing of hepatectomy for synchronous metastases of colorectal cancer is still debated. The aim of this retrospective study was to analyze prognostic factors after synchronous and delayed liver resections to define selection criteria for choosing timing of hepatectomy. Methods The study was performed on 127 patients with synchronous metastases undergoing radical hepatectomy. We divided patients according to the timing of hepatectomy: 70 synchronous (group A) and 57 delayed (group B). Results Overall survival was similar between the two groups (5-year survival 30.8% vs. 32.0% A vs. B, P = .406). The multivariate analysis evidenced four independent prognostic factors in group A: male sex (P = .04), T4 (P = .0035), more than three metastases (P = .0001), and metastatic infiltration of nearby structures (P < .0001). There were no statistically significant prognostic factors in group B. Patients with more than three metastases had a significantly worse survival in group A than in group B (3-year survival, 15.0% vs. 34.3%, P = .007); similarly, borderline significant difference was encountered in patients with T4 primary tumor (3-year survival, 16.7% vs. 60%, P = .064) Conclusions Patients with liver metastases synchronous with colorectal cancer with T4 primary tumor, metastasis infiltration of neighboring structures, and especially with more than three metastases should receive neoadjuvant chemotherapy before liver resection.  相似文献   
35.
A tension pneumothorax is a known life-threatening condition which requires a needle decompression. A diaphragmatic rupture is a relatively rare injury and is difficult to diagnose. A combination of a tension pneumothorax in presence of an ipsilateral diaphragmatic rupture can be called life-saving since the air in the pleural space is able to escape to the abdomen. The diagnosis of a diaphragmatic rupture by computed tomography or even by laparo- or thorascopy is crucial. Surgical repair should always be undertaken because the rupture will not close spontaneously and the risk of herniation of intra-abdominal organs to the pleural space will remain. In presence of a chest tube on suction, iatrogenic migration or even perforation of these organs can occur.  相似文献   
36.

Background  

Only 10–25% of patients presenting with colorectal liver metastases (CRLM) are amenable to hepatic resection. By combining resection and ablation, the number of patients eligible for surgery can be expanded. We sought to determine the efficacy of combined resection and ablation for CRLM.  相似文献   
37.
Background The prognosis of patients with papillary thyroid carcinoma (PTC) is usually favorable; however, a subset of patients can develop local recurrence or distant metastases. The aim of this study was to evaluate the prognostic factors influencing the recurrence and the survival rate in 950 PTC patients. Materials and Methods From 1990 to 2005, 950 consecutive patients affected by PTC were operated on at our Department. We analyzed the prognostic role of the following parameters: gender, age at initial treatment, extent of thyroid surgery, node dissection, tumor size, node metastases, distant metastases, stage, and 131-I therapy. Results Seventy-nine patients (8.3%) developed locoregional or distant metastases after an average follow-up of 7.8 years (range 2–17 years); in particular local recurrence was observed in 25 cases and distant metastases in 54 cases. The global 10- and 15-year survival rates were 91.38% and 88.69%, respectively. At univariate analysis, all variables were significantly correlated with recurrence (P = .001) except gender (P = .3); moreover, gender (P = .2), node dissection (P = .5), and node metastases (P = .06) were not significant on 10- and 15-year survival. At multivariate analysis the age at first treatment, T4, M+, stage IV, the extent of thyroid surgery, and the 131-I therapy resulted to be significant and independent prognostic factors (P < .001). Conclusion Our data, in disagreement with other staging systems, suggest that gender does not play a significant role both in recurrence and survival. Moreover, the 131-I therapy was a statistically significant prognostic factor at univariate and multivariate analyses.  相似文献   
38.
BACKGROUND: The impact of short-term preoperative pulmonary rehabilitation on exercise capacity of patients with chronic obstructive pulmonary disease undergoing lobectomy for non-small cell lung cancer is evaluated. METHODS: A prospective observational study was designed. Inclusion criteria consisted of an indication to lung resection because of a clinical stage I or II non-small cell lung cancer and a chronic obstructive disease on preoperative pulmonary function test. In such conditions, maximal oxygen consumption by a cardio-pulmonary exercise test was evaluated; when this resulted as being < or =15 ml/kg/min a pulmonary rehabilitation programme lasting 4 weeks was considered. Twelve patients fulfilled inclusion criteria, completed the preoperative rehabilitation programme and underwent a new functional evaluation prior to surgery. The postoperative record of these patients was collected. RESULTS: On completion of pulmonary rehabilitation, the resting pulmonary function test and diffuse lung capacity of patients was unchanged, whereas the exercise performance was found to have significantly improved; the mean increase in maximal oxygen consumption proved to be at 2.8 ml/kg/min (p<0.01). Eleven patients underwent lobectomy; no postoperative mortality was noted and mean hospital stay was 17 days. Postoperative pulmonary complication was recorded in 8 patients. CONCLUSIONS: Short-term preoperative pulmonary rehabilitation could improve the exercise capacity of patients with chronic obstructive pulmonary disease who are candidates for lung resection for non-small cell lung cancer.  相似文献   
39.
In 10 patients having deep infection after total hip replacement, we used a two-stage revision procedure involving implantation of a preformed spacer with a cylindrical rod coated with acrylic cement containing antibiotics (Spacer-G). This device, which remained in situ for an average of 5 months, permitted healing of the infection in 8 cases and reimplantation of a new prosthesis (mean follow-up 35 months). During treatment, 1 dislocation occurred. The spacer maintained the gap between both bone segments and allowed a certain degree of joint mobility. Use of Spacer-G improved the quality of life of the patients during treatment and accelerated recovery of function after reimplantation.  相似文献   
40.
Intraductal papillary mucinous neoplasms (IPMNs) are rare tumours rising from the pancreatic duct epithelium. They are characterized by intraductal papillary growth and thick mucin secretion; mucin fills the Wirsung and/or branch pancreatic ducts and may cause ductal dilatation. IPMNs are classified into three types, according to the site of involvement: main duct type, branch duct type, and combined type. Most branch type IPMNs are benign, while the other two types are frequently malignant. Recent advances in diagnostic imaging have led to an increased frequency of diagnosis of IPMNs, but the clinical features of them can range broadly from benign, borderline, and malignant non-invasive to invasive lesions, and their management has not yet been clearly defined. The most of patients are asymptomatic. The possibility of malignancy is increased in cases which large mural nodules are presented. Presence of a large branch type IPMN and marked dilatation of the main duct indicate the existence of adenoma. Not infrequently, synchronous or metachronous malignancies may be developed in various organs. Endoscopic retrograde cholangiopancreatography (ERCP), endoscopic ultrasonography (EUS), intraductal ultrasonography, and magnetic resonance cholangiopancreatography (MRCP) are the most valuable imaging techniques for diagnosis of these lesions. Prognosis is excellent after complete resection of benign and non-invasive malignant IPMNs. Total pancreatectomy should be reserved for patients with resectable but extensive IPMN involving the whole pancreas; its benefits must be balanced against perioperative risks.  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