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   468篇
  免费   23篇
  国内免费   19篇
儿科学   10篇
妇产科学   7篇
基础医学   48篇
口腔科学   2篇
临床医学   55篇
内科学   79篇
皮肤病学   11篇
神经病学   28篇
特种医学   92篇
外科学   80篇
综合类   11篇
预防医学   23篇
眼科学   2篇
药学   26篇
  1篇
肿瘤学   35篇
  2022年   2篇
  2021年   10篇
  2020年   3篇
  2019年   3篇
  2018年   9篇
  2017年   5篇
  2016年   6篇
  2015年   9篇
  2014年   11篇
  2013年   13篇
  2012年   14篇
  2011年   12篇
  2010年   23篇
  2009年   19篇
  2008年   16篇
  2007年   37篇
  2006年   18篇
  2005年   12篇
  2004年   14篇
  2003年   16篇
  2002年   12篇
  2001年   18篇
  2000年   32篇
  1999年   15篇
  1998年   17篇
  1997年   12篇
  1996年   9篇
  1995年   5篇
  1994年   8篇
  1993年   8篇
  1992年   8篇
  1991年   14篇
  1990年   2篇
  1989年   13篇
  1988年   14篇
  1987年   11篇
  1986年   10篇
  1985年   7篇
  1984年   5篇
  1983年   5篇
  1981年   3篇
  1980年   6篇
  1979年   3篇
  1976年   3篇
  1975年   4篇
  1974年   4篇
  1968年   2篇
  1967年   1篇
  1961年   1篇
  1928年   1篇
排序方式: 共有510条查询结果,搜索用时 15 毫秒
81.
Head injury in child abuse: evaluation with MR imaging   总被引:3,自引:0,他引:3  
To evaluate the usefulness of magnetic resonance (MR) imaging in the diagnosis of head injury in child abuse, the authors compared the findings at head MR imaging and computed tomography (CT) in 19 abused children. Subdural hematomas (15 cases), cortical contusions (six cases), and shearing injuries (five cases) were demonstrated to particular advantage with MR imaging. CT remained superior in the detection of subarachnoid hemorrhage. MR imaging appears to be valuable in the assessment of patients with suspected intracranial injury due to child abuse.  相似文献   
82.
Background. The influence of angiotensin converting enzyme (ACE) gene polymorphism on the progression of primary IgA nephropathy (pIgAN) is still debated. Even though the allele frequency was reported to be similar to controls, in some studies D/D patients had a faster decline of renal function and need of dialysis. Since Henoch-Schoenlein purpura (HSP) nephritis is considered a systemic vasculitis with renal lesions indistinguishable from pIgAN, we investigated the effect of the ACE polymorphism on presentation and progression of HSP IgAN. Methods. We examined the insertion (I) and deletion (D) polymorphism in intron 16 of ACE gene by PCR amplification of genomic DNA of 82 patients (37 children), with biopsy-proven IgAN associated with HSP enrolled in a collaborative study. Results. No significant association with clinical presentation at onset or with final outcome was found (functional impairment at outcome in 31.8% D/D, 27.4% I/D, and 11.1% I/I). Patients homozygous for the D allele had a greater number of extrarenal relapses (P=0.0028). No association was found between the ACE genotype and the presence of hypertension at onset and at the end of the follow-up. No difference was found between adults and children. Conclusions. In this cohort of HSP IgAN, no ACE I/D polymorphisms were found to be associated with progressive deterioration of renal function. Different genes possibly involved in vasculitis might more strictly modulate expression and evolution HSP/IgAN/  相似文献   
83.
Pancreatic transplant imaging   总被引:1,自引:0,他引:1  
Forty-four clinical episodes of suspected (pancreas) transplant rejection in 17 pancreatic transplantation patients were reviewed retrospectively. The clinical impression of acute graft rejection, chronic rejection, or nonrejection in each episode was correlated with the results of 19 nuclear medicine, 12 ultrasound (US), and 44 magnetic resonance (MR) imaging studies. US was found to be a moderately sensitive (82%) method of detecting graft rejection. US also was effective in identifying intra- and peripancreatic fluid accumulations. Nuclear medicine imaging was also a sensitive technique (86%) and the only modality that provided physiologic information regarding graft perfusion. MR imaging allowed correct prediction of the presence or absence of graft rejection in 39 of 44 cases (sensitivity, 100%; specificity, 76%) and was an effective means of detecting pathologic fluid collections. Nuclear medicine, US, and MR imaging are all believed to be sensitive methods of detecting graft rejection and are complementary adjuncts to the clinical evaluation of pancreatic transplants.  相似文献   
84.
85.
Few studies have investigated IgA nephropathy patients presenting with 'favorable' clinical features at onset, such as normal renal function, proteinuria<1 g/24 hours and the absence of hypertension, and no controlled clinical trials have tested the effects of treatment in such patients who may nevertheless develop end-stage renal disease. It is therefore important to find a well-tolerated and economic therapy capable of decreasing their risk of high proteinuria and blood pressure levels. The aim of this multicenter open-label randomized clinical trial is to test whether blocking the renin-angiotensin system (RAS) decreases the risk of progression in patients aged 3-60 years with biopsy-proven benign IgA glomerulonephritis, proteinuria levels of 0.3-0.9 g/24 hours, and normal renal function and blood pressure. The RAS is blocked by first using a single drug class (angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker), and then combining the 2 classes as soon as the 1-drug blockade has become ineffective. We plan to enroll 378 patients over the next 3 years and randomize them to receive ramipril 5 mg/day (3 mg/m2 in children) (group A), irbesartan 300 mg/day (175 mg/m 2 in children) (group B) or supportive therapy (group C); if an increase in proteinuria of at least 50% from baseline is detected after 6 months of treatment, the other RAS inhibitor will be added. The observation period will be at least 5 years (except in the case of the development of the primary end point).  相似文献   
86.
The aim of the study was to evaluate the use of Surgisis (Cook Biotech Inc.), a porcine derived extracellular matrix already used in tissue engineering, as a scaffold for neointestinal regeneration in a rat model. A 3-cm length of tubular Surgisis graft was interposed with bilateral anastomoses in the middle of an isolated ileal loop of Sprague Dawley rats with an ileostomy. The grafts were harvested and analyzed using histology and immunohistochemistry at 24 weeks after operation. Macroscopic examination revealed neither stenosis nor adhesions in the area surrounding the neointestine. The regenerated small bowel showed a mean shrinkage of 30.7% (range 20%-40%). Histologic and immunohistochemical evaluation showed a well-developed three layers of mucosa and smooth muscle and serosa in the regenerated bowel wall that were similar to those of the normal bowel with evident neovascularization. Also, the regeneration of smooth muscle fibers and innervation were evident. The preliminary results of this study showed that Surgisis allowed rapid regeneration of mucosa and smooth muscle and therefore may be a promising material for the creation of a neointestine.  相似文献   
87.

Background

The Public Health (PH) course at the medical college of Cairo University is based on traditional lectures. Large enrollment limits students' discussions and interactions with instructors.

Aim

Evaluate students' learning outcomes as measured by improved knowledge acquisition and opinions of redesigning the Reproductive Health (RH) section of the PH course into e-learning and assessing e-course utilization.

Methods

This prospective interventional study started with development of an e-learning course covering the RH section, with visual and interactive emphasis, to satisfy students' diverse learning styles. Two student groups participated in this study. The first group received traditional lecturing, while the second volunteered to enroll in the e-learning course, taking online course quizzes. Both groups answered knowledge and course evaluation questionnaires and were invited to group discussions. Additionally, the first group answered another questionnaire about reasons for non-participation.

Results

Students participating in the e-learning course showed significantly better results, than those receiving traditional tutoring. Students who originally shunned the e-course expressed eagerness to access the course before the end of the academic year. Overall, students using the redesigned e-course reported better learning experiences.

Conclusions

An online course with interactivities and interaction, can overcome many educational drawbacks of large enrolment classes, enhance student's learning and complement pit-falls of large enrollment traditional tutoring.  相似文献   
88.
89.
A duodenal volvulus is a hitherto unreported condition caused by an abnormal mobility of the third and fourth parts of the duodenum. We herein report the first such case, including its presentation, management, and possible etiology. An erratum to this article is available at .  相似文献   
90.
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