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   4649篇
  免费   9篇
  国内免费   2篇
电工技术   7篇
综合类   5篇
化学工业   93篇
金属工艺   4篇
机械仪表   8篇
建筑科学   36篇
矿业工程   3篇
能源动力   17篇
轻工业   57篇
水利工程   10篇
石油天然气   5篇
无线电   96篇
一般工业技术   124篇
冶金工业   4090篇
原子能技术   4篇
自动化技术   101篇
  2021年   7篇
  2019年   5篇
  2017年   4篇
  2016年   10篇
  2013年   31篇
  2012年   21篇
  2011年   22篇
  2010年   19篇
  2009年   16篇
  2008年   18篇
  2007年   23篇
  2006年   19篇
  2005年   21篇
  2004年   10篇
  2003年   27篇
  2002年   20篇
  2001年   12篇
  2000年   16篇
  1999年   130篇
  1998年   1259篇
  1997年   689篇
  1996年   503篇
  1995年   249篇
  1994年   223篇
  1993年   251篇
  1992年   35篇
  1991年   76篇
  1990年   68篇
  1989年   64篇
  1988年   53篇
  1987年   60篇
  1986年   47篇
  1985年   55篇
  1984年   8篇
  1983年   14篇
  1982年   29篇
  1981年   31篇
  1980年   44篇
  1979年   13篇
  1978年   15篇
  1977年   112篇
  1976年   267篇
  1975年   10篇
  1974年   5篇
  1973年   8篇
  1972年   8篇
  1971年   4篇
  1970年   4篇
  1968年   2篇
  1955年   7篇
排序方式: 共有4660条查询结果,搜索用时 15 毫秒
91.
92.
Epidermal growth factor (EGF)-induced c-fos and c-jun expression is strongly suppressed in microgravity. We investigate here whether this is due to inhibition of processes occurring during the initiation of EGF-induced signal transduction. For this purpose, EGF-induced receptor clustering is used as a marker. The lateral distribution of EGF receptors is directly visualized at an ultrastructural level by the label-fracture method. Quantification of the receptor distributions shows that EGF-induced receptor redistribution is similar under normal and microgravity conditions. This suggests that microgravity influences EGF-induced signal transduction downstream of EGF binding and EGF receptor redistribution, but upstream of early gene expression in human A431 cells.  相似文献   
93.
94.
95.
96.
97.
98.
Subcutaneous fat necrosis of the newborn (SCFN) alone is an uncommon condition. Its association with hypercalcemia has been reported in 19 neonates since 1926. The two occur in full-term to postterm newborns with perinatal complications associated with delivery. Erythematous to violaceous, firm, subcutaneous nodules appear approximately 1 to 4 weeks after delivery, preceding the development of signs and symptoms of hypercalcemia. Although SCFN and hypercalcemia are rare complications in neonates with perinatal problems, death due to the sequelae of hypercalcemia occurred in 3 of the 19 patients. A neonate who develops skin lesions consistent with SCFN should be followed for possible onset of hypercalcemia and treated in a timely fashion.  相似文献   
99.
OBJECTIVE: The objective of this review was to evaluate the clinical and research literature on professionally-led support groups for cancer patients and to propose an approach that would address patients' needs from diagnosis through survivorship. METHOD: Computerized and manual searches, including Medline and Psychlit searches, were completed for reviews of the literature. Twelve research studies were identified that met our criteria for in-depth review. A clinical model emerged from discussions of an oncology study group based on theoretical formulations and clinical experience with oncology patients. RESULTS: We found that recent research suggests that professionally-led support groups are increasing in number and that participation in such groups seems to enhance patients' quality, and possibly even quantity, of survival. Despite this, little effort has been made to determine what type of group may be appropriate for which patients and when in their course of care. CONCLUSIONS: If psychosocial intervention, in the form of professionally-led support groups for cancer patients, is to be more effective, it should be guided by a model which takes into consideration the changing needs and concerns of patients over the course of illness and, in many cases, recovery. The authors present an outline delineating what such a model might entail.  相似文献   
100.
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