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   4411篇
  免费   42篇
  国内免费   4篇
电工技术   12篇
综合类   4篇
化学工业   206篇
金属工艺   13篇
机械仪表   25篇
建筑科学   18篇
矿业工程   5篇
能源动力   31篇
轻工业   51篇
水利工程   5篇
石油天然气   2篇
无线电   153篇
一般工业技术   123篇
冶金工业   3667篇
原子能技术   6篇
自动化技术   136篇
  2023年   7篇
  2022年   25篇
  2021年   30篇
  2020年   32篇
  2019年   28篇
  2018年   29篇
  2017年   32篇
  2016年   59篇
  2015年   22篇
  2014年   37篇
  2013年   58篇
  2012年   43篇
  2011年   44篇
  2010年   35篇
  2009年   35篇
  2008年   29篇
  2007年   29篇
  2006年   18篇
  2005年   25篇
  2004年   9篇
  2003年   21篇
  2002年   9篇
  2001年   18篇
  2000年   5篇
  1999年   136篇
  1998年   1148篇
  1997年   638篇
  1996年   437篇
  1995年   227篇
  1994年   189篇
  1993年   199篇
  1992年   37篇
  1991年   67篇
  1990年   68篇
  1989年   55篇
  1988年   58篇
  1987年   59篇
  1986年   32篇
  1985年   42篇
  1984年   4篇
  1983年   6篇
  1982年   21篇
  1981年   20篇
  1980年   29篇
  1979年   8篇
  1978年   9篇
  1977年   77篇
  1976年   192篇
  1975年   6篇
  1973年   4篇
排序方式: 共有4457条查询结果,搜索用时 15 毫秒
81.
Sinus pericranii is an anomalous extracranial vascular malformation that is in continuity with the intracranial dural venous sinuses. Five case reports, three congenital and two traumatic, are described. Clinical management, including evaluation, diagnosis, and treatment, is discussed. Awareness of this entity by plastic surgeons will allow for earlier diagnosis and appropriate surgical management, resulting in decreased risk of complications.  相似文献   
82.
The impact of entrance age on reading and mathematics achievement in 1st grade was examined. Methodological problems with past research were identified, including small size of achievement differences, failure to take background variables into account, and confusion of achievement levels with degree of learning. Using a pre-post design, growth of reading and mathematics was examined in younger 1st graders, older 1st graders, and older kindergarteners. Comparisons of background information on these groups with children who were either held out prior to or retained an extra year in kindergarten, produced minimal background differences. Results revealed that younger 1st graders made as much progress over the school year as did older 1st graders and made far more progress than older kindergarteners. Overall, findings demonstrated that, in itself, entrance age was not a good predictor of learning or academic risk.  相似文献   
83.
We report a case of cervicofacial necrotizing fasciitis that developed after blepharoplasty, an occurrence that, to our knowledge, has not previously been reported in the medical literature. A patient who presented to our institution 3 days after undergoing blepharoplasty of the upper eyelid was diagnosed as having fulminant fasciitis involving extensive areas of the face, scalp, and neck. We review the case in detail and discuss clinical and radiological clues to diagnosis, surgical and medical management, wound care, and subsequent scar contracture. This case emphasizes the need for individualized, appropriate postoperative care and for an awareness of this rare, potentially fatal complication. Early recognition and aggressive treatment of cervicofacial fasciitis can arrest its rapid progression and prevent devastating sequelae.  相似文献   
84.
Access and visualization in the implant-abutment area are often compromised. Tissue impingement and lack of abutment position verification may result in inaccurate fit.  相似文献   
85.
Cognitive accounts of panic predict that panic disorder patients will be particularly prone to misinterpret autonomic sensations. Several studies have produced results consistent with this prediction, but each is open to alternative interpretation. To clarify matters, 2 studies administered the Body Sensations Interpretation Questionnaire (BSIQ) to panic patients and controls. Panic patients were more likely to interpret ambiguous autonomic sensations as signs of immediately impending physical or mental disaster and were more likely than other anxiety disorder patients and nonpatients to believe these interpretations. In a 3rd study, a brief version of the BSIQ was shown to have satisfactory test-retest reliability, to change with treatment, and to discriminate treatments that varied in their effects on panic.  相似文献   
86.
87.
88.
89.
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