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   2900篇
  免费   150篇
  国内免费   5篇
耳鼻咽喉   15篇
儿科学   175篇
妇产科学   56篇
基础医学   234篇
口腔科学   62篇
临床医学   162篇
内科学   552篇
皮肤病学   47篇
神经病学   224篇
特种医学   41篇
外科学   732篇
综合类   104篇
预防医学   121篇
眼科学   112篇
药学   144篇
中国医学   21篇
肿瘤学   253篇
  2023年   31篇
  2022年   37篇
  2021年   106篇
  2020年   53篇
  2019年   68篇
  2018年   96篇
  2017年   58篇
  2016年   88篇
  2015年   70篇
  2014年   103篇
  2013年   140篇
  2012年   211篇
  2011年   175篇
  2010年   128篇
  2009年   79篇
  2008年   135篇
  2007年   143篇
  2006年   119篇
  2005年   130篇
  2004年   128篇
  2003年   117篇
  2002年   84篇
  2001年   99篇
  2000年   78篇
  1999年   66篇
  1998年   36篇
  1997年   39篇
  1996年   25篇
  1995年   20篇
  1994年   16篇
  1993年   7篇
  1992年   33篇
  1991年   35篇
  1990年   23篇
  1989年   32篇
  1988年   28篇
  1987年   18篇
  1986年   16篇
  1985年   26篇
  1984年   19篇
  1983年   15篇
  1982年   8篇
  1981年   7篇
  1980年   13篇
  1979年   9篇
  1978年   9篇
  1976年   9篇
  1974年   15篇
  1973年   7篇
  1972年   9篇
排序方式: 共有3055条查询结果,搜索用时 15 毫秒
31.
32.
STUDY DESIGN: An in vitro investigation into the biomechanical properties of a dynamized anterolateral compression implant that allows controlled subsidence. OBJECTIVES: To determine the extent to which both modes of the anterolateral compression implant (controlled collapsing and rigid) are able to reestablish the stability of the lumbar spine after L4 corpectomy. SUMMARY OF BACKGROUND DATA: Over time, anterior and posterior spinal implants have been associated with progressive angulation, and occasionally implant failure and breakage. To circumvent this occurrence and provide better graft loading, dynamized or collapsing devices for clinical use have been developed. METHODS: Eight fresh calf spines (L1-L6) were placed in a biomechanical testing frame. Pure moments of 6 Nm were loaded onto the intact spine in six directions: flexion, extension, right and left lateral bending, and right and left axial rotation. A total L4 corpectomy then was performed, and the defect grafted with a wooden dowel. Loading was repeated after the specimens were stabilized using the two modes of the anterolateral compression implant in succession. RESULTS: The results showed that both modes of the implant (the rigid mode in particular) restore the stiffness of the unstable spine to normal levels of flexion, extension, and right and left lateral bending, even to levels exceeding normal. These devices, however, fall short of achieving normal stability in right and left axial rotation. CONCLUSION: In the cadaveric calf spine after L4 corpectomy, restoration of stability with a dynamized anterior spinal implant is possible in flexion, extension, and right and left lateral bending, but not in axial rotation.  相似文献   
33.
A rare case of a benign cerebellar astrocytoma in an adult is reported. This tumour had an extensive leptomeningeal spread in the cerebellar convexity, basal cisterns and spinal cord. The most unusual and radiologically demonstrated extension was also into the sella and Meckel's cave. The case is discussed and the literature is briefly reviewed.  相似文献   
34.
An 8-year-old boy with no evidence of von Recklinghausen's disease presented with an unusual neurinoma manifesting as a gradually progressive swelling in the suboccipital region over 2 years. The lesion was massive and had widely eroded the posterior aspects of the atlas, axis, and suboccipital bone. The tumor had involved the dura of the sigmoid and transverse sinuses, was highly vascular, and had encased the ipsilateral vertebral artery. The tumor was almost completely resected although with considerable loss of blood through a large rent in the right sigmoid sinus. This unusual benign neurinoma most probably arose from the second cervical ganglion.  相似文献   
35.
The purpose of this study was to compare self-reports of colorectal cancer (CRC) screening by fecal occult blood test (FOBT), sigmoidoscopy, and colonoscopy with medical records in a multiprovider health care setting. Relatives of CRC patients residing in Ontario, Canada completed a questionnaire indicating whether or not they had ever had any CRC screening tests. Medical records from physician's offices and hospitals were compared with the self reports, and where possible, reasons were obtained for nonmatching reports. Medical records for colonoscopies were readily available from various sources, and self-reports of this procedure were very accurate (kappa statistic for agreement beyond chance = 0.87). For sigmoidoscopy and FOBT, the agreement was poorer (kappa = 0.29 and 0.32, respectively); however, there were difficulties in obtaining records for these two procedures. Sigmoidoscopy procedures that took place many years ago were difficult to document, and physician's offices were unable to provide FOBT reports in many cases. Self-reports of colonoscopy were very accurate in this population, whereas self-reports of sigmoidoscopy and FOBT are somewhat less accurate, although this is likely due to challenges in obtaining a confirmatory record rather than an overreporting of tests. In a multiprovider publicly insured health care setting such as Canada, using self-reported information is likely to provide sufficiently accurate information for colonoscopy, but for other CRC screening tests, there may be difficulty in obtaining true estimates of the frequencies of these procedures.  相似文献   
36.
A great variety of foreign bodies in the urethra have been reported in the literature. Mostly, these cases were reported to emphasize the unusual nature of the objects requiring technical modifications for their removal. We report an interesting case of self introduced open thumb forceps into the urethra and technique of its retrieval.  相似文献   
37.
Laryngocele is an extremely rare condition. A case of external laryngocele is being reported along with a brief review on its pathogenesis, clinical presentation and management.  相似文献   
38.
Acinetobacter baumannii is emerging as a major cause of nosocomial infections particularly in high risk patients. Being resistant to adverse environmental conditions, it can stay for prolonged periods in the hospital environment. We report an outbreak in the medical oncology ward where nine patients suspected of bacteraemia were blood culture positive forA. baumannii from the two samples each, one collected through the i.v. cannula and another through the peripheral venous puncture. The bacteria was also isolated from the environmental sources from the various samples collected. The biotype, antibiogram, cellular protein profiles on SDS-PAGE and the restriction enzyme analysis patterns of the patient isolates and the environmental isolates were similar. This points to the environment as a source of infection. With reinforcement of proper barrier nursing and use of disposable heparine ampoules it was possible to control the outbreak.  相似文献   
39.
Surgery for Syringomyelia: An Analysis Based on 163 Surgical Cases   总被引:23,自引:0,他引:23  
Goel A  Desai K 《Acta neurochirurgica》2000,142(3):293-302
Summary ? Object. The authors analyzed the cases of 163 patients with syringomyelia to assess the appropriate surgical procedure. Methods. Depending on the aetiological factors and treatment considerations the series was classified into three groups. Group I were cases where there was no definite demonstrable aetiological factor; Group II cases had basilar invagination and/or Chiari malformation; and Group III consisted of cases where the syrinx was secondary to an obvious aetiology, such as a mass lesion either in the posterior cranial fossa or in the spine or a severe kyphotic spinal deformity. Post-traumatic syringomyelia and syrinx in association with spina bifida were not studied. Conclusions. We concluded that for Group I cases syringosubarachnoid shunting is the ideal form of treatment. In Group II cases foramen magnum bony decompression is satisfactory and physiological. Good results were obtained even in cases where either a foramen magnum decompression alone or in combination with a syringo-subarachnoid shunt was done. Only syringosubarachnoid shunt (without a foramen magnum decompression) in Group II cases was found to produce poor outcome. Group III cases should be treated for the primary aetiological problem. Only syrinx drainage procedure without treatment of aetiology in these cases produced poor results. It was observed that clinical outcome rather than radiological improvement is the reliable indicator of the surgical result.  相似文献   
40.
Perspectives on colorectal cancer screening: a focus group study   总被引:3,自引:0,他引:3  
Objective To assess attitudes and acceptability of Ontario consumers and doctors towards colorectal screening with faecal occult blood testing (FOBT) and colonoscopy. Design, setting and participants Focus groups with gender‐specific samples of the population, high‐risk gastroenterology patients and family doctors. Method Semi‐structured interview guides used by facilitator to lead groups through knowledge of risk factors and prevention of colorectal cancer, the screening modalities, requirements for implementing screening programmes, barriers to screening and preferences towards screening. Main findings There were low levels of knowledge about colorectal cancer and its prevention in the general population. FOBT was an acceptable screening modality, but considerable education about its use and benefits would be necessary to implement a screening programme. Colonoscopy was not perceived to be a good choice for a primary screen in the general population. The high‐risk group supported use of FOBT in the general population and emphasized the need for education. The doctors were more reluctant about screening, requesting clear guidelines. They also identified the time and resources that would be required if a screening programme were initiated. Conclusion While colorectal screening is acceptable in this sample, information and decision aids are required to enable consumers and providers to make effective decisions. Implementation of colorectal screening programmes requires substantial educational efforts for both consumers and doctors.  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