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   2448747篇
  免费   172257篇
  国内免费   4811篇
耳鼻咽喉   33021篇
儿科学   80099篇
妇产科学   67024篇
基础医学   348859篇
口腔科学   70926篇
临床医学   221290篇
内科学   469658篇
皮肤病学   55738篇
神经病学   189610篇
特种医学   93427篇
外国民族医学   437篇
外科学   369679篇
综合类   53885篇
现状与发展   5篇
一般理论   757篇
预防医学   179955篇
眼科学   57936篇
药学   184982篇
  13篇
中国医学   6179篇
肿瘤学   142335篇
  2021年   18325篇
  2019年   18986篇
  2018年   27544篇
  2017年   21164篇
  2016年   23517篇
  2015年   26613篇
  2014年   36733篇
  2013年   53801篇
  2012年   74159篇
  2011年   78176篇
  2010年   46356篇
  2009年   43317篇
  2008年   72423篇
  2007年   77304篇
  2006年   77948篇
  2005年   74509篇
  2004年   71668篇
  2003年   68465篇
  2002年   65922篇
  2001年   127897篇
  2000年   130911篇
  1999年   108556篇
  1998年   28404篇
  1997年   24848篇
  1996年   24936篇
  1995年   23822篇
  1994年   21751篇
  1993年   20323篇
  1992年   81999篇
  1991年   79089篇
  1990年   76864篇
  1989年   73779篇
  1988年   67073篇
  1987年   65345篇
  1986年   61763篇
  1985年   58538篇
  1984年   42860篇
  1983年   36489篇
  1982年   20496篇
  1979年   38169篇
  1978年   26243篇
  1977年   22833篇
  1976年   20714篇
  1975年   22525篇
  1974年   26917篇
  1973年   25942篇
  1972年   24220篇
  1971年   22610篇
  1970年   20911篇
  1969年   19776篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
Genetic disorders of mineral metabolism cause urolithiasis, renal disease, and osteodystrophy. Most are rare, such that the full spectrum of clinical expression is difficult to appreciate. Diagnosis is further complicated by overlap of clinical features. Dent's disease and primary hyperoxaluria, inherited causes of calcium urolithiasis, are both associated with nephrocalcinosis and urolithiasis in early childhood and renal failure that can occur at any age but is seen more often in adulthood. Bone disease is an inconsistent feature of each. Dent's disease is caused by mutations of the CLCN-5 gene with impaired kidney-specific CLC-5 chloride channel expression in the proximal tubule, thick ascending limb of Henle, and the collecting ducts. Resulting hypercalciuria and proximal tubule dysfunction, including phosphate wasting, are primarily responsible for the clinical manifestations. Low-molecular-weight proteinuria is characteristic. Definitive diagnosis is made by DNA mutation analysis. Primary hyperoxaluria, type I, is due to mutations of the AGXT gene leading to deficient hepatic alanine–glyoxylate aminotransferase activity. Marked overproduction of oxalate by hepatic cells results in the hyperoxaluria responsible for clinical features. Definitive diagnosis is by liver biopsy with measurement of enzyme activity, with DNA mutation analysis used increasingly as mutations and their frequency are defined.

Conclusion


These disorders of calcium urolithiasis illustrate the value of molecular medicine for diagnosis and the promise it provides for innovative and more effective future treatments.  相似文献   
43.
44.

Background  

The Association of Surgeons of Great Britain and Ireland (ASGBI) devised the electronic surgical logbook (version 2.4) for higher trainees in General Surgery enabling trainees to compile a uniform data set of their operative and training experience. This is in use by higher surgical trainees (HST) in the United Kingdom. This logbook permits trainees to submit data centrally into a Regional Analysis Database (RAD). With the implementation of the European Working Time Directive (EWTD) there is need for reliable data to assess the effects of the directive on training. In order to draw meaningful conclusions from the database the quality of data needs to be validated. We critically analysed the RAD in the Yorkshire region for a one-year period.  相似文献   
45.
46.
47.
BACKGROUND: The laparoscopic resection of rectal cancer shows morbidity and oncological safety comparable to the open approach, but morbidity increases after conversion to open resection. No oncological long-term results are available for the latter patients. METHODS: From 01/01/2000-31/12/2002, patients with curatively resected rectal cancer enrolled in a observational study were evaluated for morbidity, mortality, tumor- and local recurrence rate, paying attention to patients with conversion from laparoscopic to open resection. RESULTS: 237 (3.3%) of 7,189 patients underwent laparoscopic resection (ITT). These patients showed significantly more T1/2 tumors (P<0.001) in earlier UICC stages (P<0.001) than open resected patients. 35 (14.8%) of 237 laparoscopic procedures were converted. Compared with patients receiving complete laparoscopic or open resection, these patients showed significantly higher frequencies of intraoperative (P<0.001) and general postoperative complications (P=0.003) as well as the highest overall morbidity (P=0.031). After a median follow-up of 30.1 months, the highest 5-year local recurrence rate was found in the converted group (16.0%). The laparoscopically resected patients showed a local recurrence rate of 3.3%, patients with open resection of 12.4% (P=0.082). The disease-free survival rate did not differ between the groups (P=0.585). CONCLUSION: Laparoscopic resection of rectal cancer provides oncological results similar to open resection. After conversion, the short and oncological long-term outcomes were worse. Considering a conversion rate of 15%, only a strict indication for the laparoscopic approach can be allowed, and laparoscopic resection should be performed at centers.  相似文献   
48.
49.
50.
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