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   566篇
  免费   27篇
  国内免费   7篇
耳鼻咽喉   1篇
儿科学   36篇
妇产科学   2篇
基础医学   45篇
口腔科学   18篇
临床医学   40篇
内科学   155篇
皮肤病学   8篇
神经病学   10篇
特种医学   79篇
外科学   65篇
综合类   68篇
预防医学   25篇
眼科学   8篇
药学   20篇
肿瘤学   20篇
  2023年   2篇
  2022年   5篇
  2021年   10篇
  2020年   5篇
  2019年   2篇
  2018年   6篇
  2017年   4篇
  2016年   9篇
  2015年   16篇
  2014年   11篇
  2013年   17篇
  2012年   8篇
  2011年   9篇
  2010年   19篇
  2009年   32篇
  2008年   11篇
  2007年   21篇
  2006年   33篇
  2005年   12篇
  2004年   18篇
  2003年   7篇
  2002年   11篇
  2001年   13篇
  2000年   15篇
  1999年   13篇
  1998年   42篇
  1997年   31篇
  1996年   41篇
  1995年   17篇
  1994年   18篇
  1993年   22篇
  1992年   6篇
  1991年   8篇
  1990年   2篇
  1989年   9篇
  1988年   24篇
  1987年   9篇
  1986年   8篇
  1985年   17篇
  1984年   7篇
  1983年   4篇
  1982年   3篇
  1981年   3篇
  1980年   3篇
  1977年   3篇
  1976年   5篇
  1975年   4篇
  1973年   1篇
  1970年   2篇
  1969年   1篇
排序方式: 共有600条查询结果,搜索用时 15 毫秒
21.
22.
To assess the dosimetric effect of using interpolated contours in planning intensity‐modulated radiation therapy (IMRT) for advanced T‐stage nasopharyngeal carcinoma. The present study focused on T3–T4 tumours where the proximity of targets to neurological organs poses a stringent test on the feasibility of such an approach. Contours of targets and organs were delineated on CT images of 2.5‐mm interval and a reference IMRT plan was generated. An investigative (INV) IMRT plan was then generated with the same planning protocol, but based on interpolated contours that replaced deleted contours on alternate slices. The reference and INV plans were compared. Regarding target coverage, all targets in the INV plans met the acceptance criteria except for the PTV in one case. Regarding organs, the mean dose to 1% volume of the brainstem and spinal cord in the INV plans were kept below their dose limits. No significant differences in the mean doses to others organs were found. Satisfactory target coverage and protection of critical organs to a degree similar to full‐scale contouring could be achieved with use of interpolated contours. The saving in manpower time for contouring is expected to significantly improve the throughput of the IMRT planning process.  相似文献   
23.
Demographic, clinical and laboratory data were retrospectively collected from records of 146 cases of CT fluoroscopy‐guided chemical lumbar sympathectomy for the palliation of inoperable peripheral vascular disease (PVD) between January 1997 and August 1999. Of these, 16% had claudication, 39% had rest pain and 44% had ischaemic ulcers or gangrene. Seventy‐three percent of elective cases were outpatients. At 3 months, 27 cases were lost to follow up, leaving 119 cases. Within 3 months, improvement, defined as doubling of the walking distance, cessation of rest pain or healing of ulcers, occurred in 30.3% of cases. No change was observed in 45.4% of cases and 24.3% of cases deteriorated. Patients with ulcers or gangrene had significantly poorer results than those without any ischaemic lesions, as only 19% versus 39% of patients improved (P < 0.05). The presence of hypertension, diabetes mellitus, hyperlipidaemia and smoking had no value in predicting clinical outcome (P > 0.05). There were no major complications noted. CT fluoroscopy‐guided chemical lumbar sympathectomy is safe and effective, with a complication rate of less than 1%, and efficacy of at least 30% measured within 3 months. It is a simple and minimally invasive procedure, easily performed on an outpatient basis. CT fluoroscopy‐guided chemical lumbar sympathectomy should be considered for all patients in the early stages of inoperable PVD.  相似文献   
24.
Recently, the beneficial role of steroids for acute laryngotracheobronchitis has been more clearly defined for both intubated and unintubated patients. However, corticosteroids also improve the clinical signs of airway haemangiomata. Two patients are described who illustrate how this can be a source of diagnostic confusion.  相似文献   
25.
26.
Roxatidine acetate, a new H2 receptor antagonist, was compared with ranitidine in the treatment of duodenal ulcers in a double-blind multicentre study. Eighty-four patients with endoscopically proven duodenal ulcer were randomized to receive 150 mg roxatidine acetate or 300 mg ranitidine at bedtime. Repeat endoscopy was performed after 4 weeks (25–33 days) and if the ulcer had not healed, another endoscopy was performed after a further 4 weeks of treatment. Using per protocol analysis 73.6% of ulcers treated with roxatidine healed at 4 weeks compared to 72.2% of ulcers treated with ranitidine (P=NS). The healing rates at 8 weeks were 92% with roxatidine and 83.3% with ranitidine (P=NS). Using equivalence tests, the healing rate of roxatidine was found to be equivalent to that of ranitidine within a 20% region. Roxatidine users took significantly less antacids than ranitidine users (P < 0.05). There were no significant adverse effects due to roxatidine or ranitidine. Roxatidine is a safe effective drug in the treatment of duodenal ulcers with a healing rate comparable to that of ranitidine.  相似文献   
27.
28.
29.
OBJECTIVES: This study reviewed a consumer-oriented process for recruiting research volunteers age 65 or older for an osteoporosis clinical trial. METHODS: Odds ratios were used to estimate the relative importance of methods to enroll research volunteers from three racial or ethnic groups. RESULTS: Nine hundred and four women were screened; 168 African American, White, and Hispanic women enrolled. Mailings and media were effective when the target population was large and knowledgeable about the disease and treatment being investigated. Efficiency of mailings was increased when individuals in the mailing list were familiar with research and the research center. An interpersonal approach was more effective than a media-based approach when the target population was small, unaware of their personal risk of the disease, and unfamiliar with research and research center. DISCUSSION: Information on the characteristics of potential volunteers and their communities will enable readers to evaluate the applicability of recruitment methods used.  相似文献   
30.
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