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   2083篇
  免费   0篇
化学工业   16篇
轻工业   3篇
石油天然气   1篇
一般工业技术   1篇
冶金工业   2058篇
自动化技术   4篇
  2015年   1篇
  2013年   2篇
  2011年   1篇
  2010年   1篇
  2009年   1篇
  2008年   1篇
  2007年   3篇
  2005年   2篇
  2004年   1篇
  2003年   4篇
  2001年   2篇
  2000年   2篇
  1999年   82篇
  1998年   653篇
  1997年   353篇
  1996年   226篇
  1995年   143篇
  1994年   116篇
  1993年   111篇
  1992年   15篇
  1991年   14篇
  1990年   15篇
  1989年   23篇
  1988年   22篇
  1987年   24篇
  1986年   20篇
  1985年   20篇
  1983年   5篇
  1982年   7篇
  1981年   14篇
  1980年   13篇
  1979年   2篇
  1978年   5篇
  1977年   62篇
  1976年   93篇
  1975年   5篇
  1974年   2篇
  1973年   3篇
  1972年   2篇
  1971年   2篇
  1970年   2篇
  1969年   1篇
  1968年   1篇
  1965年   1篇
  1964年   2篇
  1961年   1篇
  1960年   1篇
  1959年   1篇
排序方式: 共有2083条查询结果,搜索用时 15 毫秒
31.
32.
Ss discussed topics with an interviewer (I) whose comments were controlled by a motor response made by S. In Exp. I, there was less increase in silence over trials, more negative attitude toward the I, and longer delay after I responses when these were interpretations rather than reflections. With a choice between interpretation and reflection, several personality differences were found between Ss preferring one rather than the other of the two classes of I response. Ss in Exp. 1 requested an I response less frequently when he disagreed with them, but only under conditions in which Ss were told the I would try to influence them. Under influence instructions there was a positive correlation between frequency of I responses and negative attitude toward him. In Exp. 3, frequency of I response was maintained over trials only for Ss high on the Social Desirability Scale. The attitude of high SD Ss was more negative when emotional, rather than neutral, topics were discussed. (15 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
33.
A system is described which enables crosswords to be automatically compiled or solved, or which alternatively may assist in their manual compilation or solution. Illustrative examples are quoted and the performance of the system, which has been written for an Acorn BBC model B microcomputer with disc pack and printer, is discussed.  相似文献   
34.
The time course of skin tumor induction was determined in hair-clipped inbred agouti C3Hf mice irradiated three times per week with a medium-pressure quartz-mercury lamp; 4 different UV doses were used. Although the ears were also exposed to the radiation, in the 3 groups given the highest doses no ear tumors were observed by the time each animal had developed at least 1 tumor on its back. No tumors were found in the animals receiving the lowest UV dose. In the group receiving the highest dose, males developed tumors earlier than did females; this trend continued in the lower dose groups. Many tumors that developed in the back skin were well-differentiated squamous cell carcinomas. Others were less well-differentiated squamous cell carcinomas. Others were less well defined so that the cell of origin was difficult to determine. In the group receiving the highest UV dose, the squamous cell carcinomas were few, whereas at the lower doses they predominated.  相似文献   
35.
36.
Since the inception of mobile coronary care units (MCCU), patients with sudden cardiac death (SCD) saved by advanced emergency medical technicians (EMT-A) can be studied retrospectively and prospectively. Forty-eight cases of SCD found in ventricular fibrillation (VF) were successfully resuscitated. Only 32% had a myocardial infarction. Most survivors were New York Heart Association (NYHA) class I or II. All class IV survivors with severe congestive heart failure died within 45 days. All class II survivors had angina as the limiting factor. Of all patients with VF, 23% survived. Eighty percent of survivors were class I or II and have resumed previous lifestyles. No clear cut symptom complex was identified. Rescue response time was generally less than five minutes. Intracardiac medications were administered without complications. Empirical administration of sodium bicarbonate correlated poorly with arterial blood gas determinations.  相似文献   
37.
The effect of nitric oxide (NO) donors on high-voltage-activated Ca2+ channels in insulin-secreting RINm5F cells was investigated using the patch-clamp technique in the whole-cell configuration. Sodium nitroprusside (SNP, 2-400 microM) induced a dose-dependent reduction in Ba2+ currents with maximal inhibition of 58%. The IC50 for SNP was 45 microM. A different NO donor, (+/-)S-nitroso-N-acetylpenicillamine (SNAP, 500 microM), also produced a 50% decrease in current amplitude. When 200 microM SNP was administered together with the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidozoline-1-oxyl-3-oxide (carboxy-PTIO, 300 microM), the Ba2+ current inhibition was lowered to 7%. Administration of 500 microM 8-bromoguanosine 3':5'-cyclic monophosphate sodium salt (8-Br-cGMP) mimicked the effects of SNP, causing a comparable decrease (56%) in peak-current amplitude. When soluble guanylyl cyclase was blocked by 10 microM 1H-[1,2, 4]oxadiazole[4,3-a]quinoxalin-1-one (ODQ), the inhibitory effect of 200 microM SNP was reduced from 39% to 15%. The SNP-induced current decrease was 36% of controls after the blockade of L-type Ca2+ channels and 30% in the presence of 2.5 microM omega-conotoxin-MVIIC. These data indicate that NO inhibits both L-type and P/Q-type Ca2+ channels in RINm5F cells, probably by an increase in the intracellular levels of cGMP. NO may then significantly influence the Ca2+-dependent release of hormones from secretory cells as well as that of neurotransmitters from nerve terminals.  相似文献   
38.
39.
A group of public health scientists from the United States and The Netherlands met at a Bicentennial Round Table Conference December 1-2, 1982, to discuss the latest developments in immunization against infectious diseases, focusing on pertussis, poliomyelitis, measles, and rubella. The major differences in immunization practices in the two countries are: (a) In The Netherlands, inactivated polio vaccine is used exclusively; in the United States, the oral polio vaccine is used. Polio-myelitis has virtually disappeared from both countries. (b) In The Netherlands, the pertussis component of DTP (diphtheria, tetanus, pertussis) is not given to children over the age of 1 year, whereas in the United States, it is given to children up to their seventh birthday. (c) Rubella vaccine is given only to girls at ages 11-12 years in The Netherlands, but to all children at ages 12-15 months in the United States. (d) Mumps vaccine is not administered to children in The Netherlands, but in the United States it is given routinely to children at 12-15 months (in combination with measles and rubella vaccine). The participants concluded that both the United States and The Netherlands have effective immunization programs that have significantly reduced the impact of these diseases.  相似文献   
40.
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