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   6959篇
  免费   409篇
  国内免费   26篇
耳鼻咽喉   51篇
儿科学   109篇
妇产科学   107篇
基础医学   901篇
口腔科学   151篇
临床医学   568篇
内科学   2162篇
皮肤病学   126篇
神经病学   689篇
特种医学   161篇
外科学   955篇
综合类   73篇
一般理论   1篇
预防医学   470篇
眼科学   164篇
药学   410篇
中国医学   10篇
肿瘤学   286篇
  2023年   37篇
  2022年   28篇
  2021年   243篇
  2020年   115篇
  2019年   167篇
  2018年   238篇
  2017年   122篇
  2016年   203篇
  2015年   189篇
  2014年   279篇
  2013年   325篇
  2012年   535篇
  2011年   566篇
  2010年   342篇
  2009年   288篇
  2008年   451篇
  2007年   512篇
  2006年   493篇
  2005年   413篇
  2004年   410篇
  2003年   337篇
  2002年   326篇
  2001年   69篇
  2000年   68篇
  1999年   64篇
  1998年   67篇
  1997年   46篇
  1996年   32篇
  1995年   32篇
  1994年   32篇
  1993年   40篇
  1992年   37篇
  1991年   25篇
  1990年   17篇
  1989年   16篇
  1988年   18篇
  1987年   9篇
  1986年   12篇
  1984年   19篇
  1983年   23篇
  1982年   20篇
  1981年   21篇
  1980年   13篇
  1978年   7篇
  1977年   16篇
  1976年   10篇
  1975年   5篇
  1974年   11篇
  1970年   5篇
  1969年   6篇
排序方式: 共有7394条查询结果,搜索用时 171 毫秒
1.
2.
3.
4.
5.
OBJECTIVES: To determine whether aromatase expression in the eutopic endometrium and adenomyotic foci is affected by previous use of oral contraceptives containing gestodene, and to determine whether changes in cyclooxygenase-2 (COX-2) expression occur in adenomyosis during the menstrual cycle. PATIENT AND METHODS: This was a retrospective cohort study carried out in paraffin-embedded endometrial tissue obtained from patients with a histological diagnosis of adenomyosis obtained during the proliferative (n = 25) and luteal (n = 10) phases of the menstrual cycle and following the use of continuous oral contraception with gestodene/ethinyl estradiol (n = 7). COX-2 and aromatase expression were measured in both eutopic endometrium and adenomyotic foci using immunohistochemical methods. RESULTS: Aromatase expression was detected in 80% of the endometrial slices by immunohistochemistry. In positive cases, aromatase was mainly detected in the stromal cells of the eutopic endometrium, whereas in the adenomyotic foci this expression was negative in the majority of the cases. Oral contraceptives containing gestodene, on the other hand, were effective in suppressing aromatase expression in both eutopic and ectopic endometrium. COX-2 expression was detected by immunohistochemistry in the glandular epithelium of both eutopic endometrium and adenomyotic foci and there were no significant changes in its intensity throughout the menstrual cycle. CONCLUSION: Aromatase expression in the eutopic endometrium and adenomyotic foci is suppressed by oral contraceptives containing gestodene. Increased aromatase activity may be responsible for the persistent COX-2 expression during the luteal phase.  相似文献   
6.
7.
Ureteral herniation is a rare entity. We report the first case of extraperitoneal ureteral herniation in a pediatric en bloc renal graft causing obstructive uropathy. A 70-year-old, obese patient with an en bloc renal transplant was found to have ureterohydronephrosis in the right renal graft on magnetic resonance imaging. Nephrostomy with insertion of a double-J catheter confirmed the presence of a ureteral loop within the inguinal tract. Surgery confirmed herniation of the ureter through the internal inguinal ring, crossing over the spermatic cord. We performed release, resection, ureteral reimplantation and hernioplasty. Four months later, renal function was normal and urinary tract dilation had diminished. This case illustrates an unusual cause of obstructive uropathy in a transplanted kidney. Apart from obesity, two other factors may have contributed to its development: presence of a redundant ureter, and the fact that the ureter had been placed over, rather than under, the spermatic cord.  相似文献   
8.
Background contextLarge, prominent osteophytes along the anterior aspect of the cervical spine have been reported as a cause of dysphagia. Improvement of swallowing after surgical resection has been reported in a few case reports with short-term follow-up. The current report describes outcomes of a series of five patients with surgical treatment for this rare disorder, with a long-term follow-up.PurposeTo study the clinical and radiographic outcomes of a case series of patients surgically treated for dysphagia secondary to cervical diffuse idiopathic skeletal hyperostosis (DISH).Study designRetrospective review of a case series.Patient sampleFive cases from a University Hospital.Outcome measuresClinical and imagenological follow-up.MethodsThe records of five patients with dysphagia who had undergone anterior surgical resection of prominent osteophytes secondary to DISH were reviewed. Extrinsic esophageal compression secondary to anterior cervical osteophytes was radiographically confirmed via preoperative barium esophagogram swallowing study. All patients underwent anterior cervical osteophytes resection without fusion. Postoperatively, patients were followed-up clinically and radiographically with routine lateral cervical radiographs.ResultsPreoperative esophagogram showed that the esophageal obstruction was present at one level in three cases and two levels in two cases. The C3–C4 level was involved in three cases, C4–C5 in three cases, and C5–C6 in one case. There were no postoperative complications, including recurrent laryngeal nerve palsy, wound infection, or hematomas. All patients had resolution of dyphagia soon after surgery (within 2 weeks). Postoperative radiographs demonstrated complete removal of osteophytes. At final follow-up, ranging from 1 to 9 years (average 59.8 months, median 53 months), no patients reported recurrence of dysphagia. Final radiographic examination demonstrated minimal regrowth of the osteophytes.ConclusionsAlthough rarely indicated, surgical resection of anterior cervical osteophytes from DISH causing dyphagia produces good clinical and radiographical outcomes. After thorough evaluation to rule out other intrinsic or extrinsic causes of swallowing difficulty, surgical treatment of this uncommon condition might be considered.  相似文献   
9.
OBJECTIVE: To study the effect of seasons on the health-related quality of life (HRQL) of asthmatic children. METHODS: Four groups of asthmatic children 7 to 14 years old were recruited by pediatricians during each season of the year. Their HRQL was assessed by means of the Paediatric Asthma Quality of Life Questionnaire (PAQLQ). Other factors surveyed were asthma severity, atopy, medical treatment, immunotherapy, obesity, parental smoking, and anti-allergic measures. RESULTS: The mean (SD) overall PAQLQ score was highest in summer at 6.2 (1.0) and lowest in autumn at 5.5 (1.2). The same trend was found for domains in summer and autumn, respectively: symptoms, 6.2 (1.0) vs 5.4 (1.4); emotions, 6.5 (0.8) vs 6.0 (1.0); and activities, 5.9 (1.4) vs. 5.0 (1.5). Factors such as male gender (odds ratio [OR], 0.60; 95% confidence interval [CI], 0.41-0.87), being on immunotherapy (OR, 0.59; 95% CI, 0.38-0.92), living in an urban environment (OR, 0.56; 0.33-0.93), and residing on the northern coast of Spain along the Bay of Biscay (OR, 0.56; 0.36-0.89) were independent protective factors against having a total PAQLQ score in the lower tertile. Conversely, being recruited in a primary care setting (OR, 1.55; 1.01-2.38) and having more severe asthma were risks for being in the lower tertile. CONCLUSIONS: Irrespective of the severity of the disease, season has a significant influence on the HRQL of asthmatic children.  相似文献   
10.
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