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   1478篇
  免费   0篇
  国内免费   1篇
化学工业   2篇
金属工艺   1篇
机械仪表   1篇
能源动力   2篇
轻工业   1篇
石油天然气   1篇
无线电   1篇
一般工业技术   2篇
冶金工业   1466篇
自动化技术   2篇
  2013年   2篇
  2011年   1篇
  2009年   1篇
  2007年   1篇
  2006年   1篇
  2005年   1篇
  2003年   4篇
  1999年   40篇
  1998年   427篇
  1997年   246篇
  1996年   158篇
  1995年   90篇
  1994年   81篇
  1993年   102篇
  1992年   6篇
  1991年   23篇
  1990年   18篇
  1989年   19篇
  1988年   27篇
  1987年   20篇
  1986年   16篇
  1985年   9篇
  1983年   4篇
  1982年   3篇
  1981年   12篇
  1980年   19篇
  1979年   1篇
  1978年   3篇
  1977年   43篇
  1976年   91篇
  1975年   6篇
  1973年   1篇
  1969年   1篇
  1955年   2篇
排序方式: 共有1479条查询结果,搜索用时 15 毫秒
61.
A large body of literature indicates that the serotonergic system is involved in behavioral regulation, as evidenced by the inverse relationship between impulsive aggression and serotonergic function found in adult alcoholics and nonalcoholics. However, studies of this relationship among child and adolescent offspring of alcoholics (COAs) have not previously been done. This study examines the potentially parallel relationship between behavioral dysregulation and low serotonergic function in young COAs. The relationship is of potential interest as a phenotypic marker of biological vulnerability to aggressiveness, which itself has been hypothesized to be a risk factor for later antisocial alcoholism. The present work is part of an ongoing prospective study of the development of risk for alcohol abuse/dependence and other problematic outcomes in a sample of families subtyped by the fathers' alcoholism classification. We examined the relationship between overt behavior problems in middle childhood (mean age = 10.5 +/- 1.7 years) and whole blood serotonin (5-HT) in a subsample of the offspring (N = 32 boys and 12 girls). Using a Child Behavior Checklist (CBCL) index of behavioral undercontrol, we obtained results indicating that high total behavior problem (TBP) children had lower levels of whole blood 5-HT than did low-TBP children (p < 0.01). These results support the hypothesis that there is an inverse relationship between whole blood serotonin levels and behavior problems in young male and female COAs. A father's alcoholism status was not significantly related to his child's 5-HT level, i.e., the child's phenotypic expression of behavioral dysregulation was more reliably connected to serotonergic function than was paternal alcoholism.  相似文献   
62.
63.
After burn or resection of one submandibular salivary gland the contralateral gland responded by an increase of proliferation. The maximal mitotic index was observed 48 hours after the resection and 72 hours after the burn. Burn of the salivary gland initiated a stable, but weak compensatory hypertrophy of the contralateral gland. Hypertrophy of the gland was accompanied by an increase in the size of the cells and the nuclei whose area enlarged by 10 and 17%, respectively. Resection of the salivary gland caused an increase in the weight of the intact contralateral gland only at the early periods of the experiment. By the 30th and the 45th day after the operation the weight of the intact contralateral gland failed to differ from control. The detected differences in the compensatory growth of the intact glands in two types of action on the contralateral salivary gland depended on the quantity of the tissue degeneration products and on the period of their stay in the organism.  相似文献   
64.
65.
Severe hemophiliacs with intractable bleeding into one or more joints despite adequate clotting factor replacement therapy are difficult management problems. Synovectomy has controlled bleeding only in joints without significant arthritis destruction. Total joint replacements have been performed in arthropathic joints, but not when uncontrolled bleeding was a concurrent problem. This report describes a hemophiliac with uncontrolled bleeding into an arthritic knee who was successfully managed by combining synvectomy with total knee replacement.  相似文献   
66.
67.
An outbreak of spirochetosis occurred in a flock of 75 game chickens in California during fall 1991. Affected birds were weak and anemic. Many had greenish diarrhea. Spirochetes were seen on Giemsa-stained blood smears and in silver-stained tissue sections of kidney, liver, and spleen. Splenomegaly, which is reported to be characteristic of fowl spirochetosis, was not observed in two acutely infected chickens.  相似文献   
68.
69.
Capsules filled with mixtures of verapamil, hydroxypropoxyl cellulose (HPC), and effervescent are proposed to provide floating sustained release over 10 hr. The effects of weight filled in the capsule, amount of HPC, and the addition of effervescent on the dissolution kinetics are studied. The conventional capsules were filled with different amounts and weights of the mixtures of verapamil, HPC, and effervescent. The release of verapamil from the capsules followed the Higuchi release model. However, when effervescent was added, a zero-order drug release was observed after the burst phase. The conventional capsule, when filled with active ingredients, polymers, and effervescent, can achieve a zero-order release system. Entrapped air was considered as a barrier to diffusion and matrix relaxation in drug release.  相似文献   
70.
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