全文获取类型
收费全文 | 1375篇 |
免费 | 11篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 11篇 |
化学工业 | 81篇 |
金属工艺 | 18篇 |
机械仪表 | 16篇 |
建筑科学 | 23篇 |
矿业工程 | 1篇 |
能源动力 | 10篇 |
轻工业 | 79篇 |
水利工程 | 3篇 |
石油天然气 | 2篇 |
无线电 | 176篇 |
一般工业技术 | 80篇 |
冶金工业 | 697篇 |
原子能技术 | 3篇 |
自动化技术 | 190篇 |
出版年
2022年 | 5篇 |
2018年 | 6篇 |
2016年 | 5篇 |
2015年 | 19篇 |
2014年 | 8篇 |
2013年 | 28篇 |
2012年 | 20篇 |
2011年 | 29篇 |
2010年 | 20篇 |
2009年 | 33篇 |
2008年 | 29篇 |
2007年 | 45篇 |
2006年 | 37篇 |
2005年 | 27篇 |
2004年 | 34篇 |
2003年 | 25篇 |
2002年 | 28篇 |
2001年 | 19篇 |
2000年 | 35篇 |
1999年 | 36篇 |
1998年 | 180篇 |
1997年 | 115篇 |
1996年 | 85篇 |
1995年 | 60篇 |
1994年 | 43篇 |
1993年 | 37篇 |
1992年 | 20篇 |
1991年 | 9篇 |
1990年 | 29篇 |
1989年 | 16篇 |
1988年 | 21篇 |
1987年 | 12篇 |
1986年 | 15篇 |
1985年 | 23篇 |
1984年 | 10篇 |
1983年 | 17篇 |
1982年 | 13篇 |
1981年 | 12篇 |
1980年 | 10篇 |
1979年 | 6篇 |
1978年 | 15篇 |
1977年 | 24篇 |
1976年 | 42篇 |
1975年 | 12篇 |
1974年 | 10篇 |
1973年 | 11篇 |
1972年 | 7篇 |
1971年 | 5篇 |
1969年 | 6篇 |
1961年 | 4篇 |
排序方式: 共有1390条查询结果,搜索用时 15 毫秒
91.
Friedman Herbert; Thompson Robert B.; Rosen Ellen F. 《Canadian Metallurgical Quarterly》1985,94(4):624
In Study 1, 12 undergraduates informed only of the normal physiological reactions to hand immersion in cold water and 12 Ss informed that they were participating in a "study of the perception of novel stimuli" showed much greater tolerance and reported significantly less pain than did 12 controls given no pretesting message. Therefore, giving Ss the chance to ascribe uncomfortable sensations to a nondamaging process increased tolerance. Study 2, with 5 graduate students, showed that repeated exposure to cold-water immersion (employed to demonstrate safety of the procedure) did not reduce the reported sensation of pain, indicating that the increased tolerance following assurances of safety was directly due to decreased threat and not to decreased sensation. Findings support the distinction between pain sensation and emotional-motivational reaction leading to escape or avoidance. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
92.
Goutsias J. Mendel J.M. 《IEEE transactions on pattern analysis and machine intelligence》1989,11(9):990-998
The authors present the class of semi-Markov random fields and deal, in particular, with the subclass of discrete-valued, nonsymmetric half-plane, unilateral Markov random fields. A hierarchical nonstationary-mean nonstationary-variance (NMNV) image model is proposed for the modeling of nonstationary and noisy images. This model seems to be advantageous as compared to a regular NMNV model because it statistically incorporates the correlation between pixels around the boundary of two adjacent regions. The hierarchical NMNV model leads to the development of an optimal algorithm that allows the simultaneous segmentation and model estimation of measured images. Although no theoretical result is available for the consistency of the estimated model parameters, the method seems to work sufficiently well for the examples considered 相似文献
93.
Six studies explore the role of goal shielding in self-regulation by examining how activation of focal goals to which the individual is committed inhibits the accessibility of alternative goals. Consistent evidence was found for such goal shielding, and a number of its moderators were identified: Individuals' level of commitment to the focal goal, their degree of anxiety and depression, their need for cognitive closure, and differences in their goal-related tenacity. Moreover, inhibition of alternative goals was found to be more pronounced when they serve the same overarching purpose as the focal goal, but lessened when the alternative goals facilitate focal goal attainment. Finally, goal shielding was shown to have beneficial consequences for goal pursuit and attainment. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
94.
Mezhiba A.V. Friedman E.G. 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》2002,10(6):762-776
The design of high integrity, area efficient power distribution grids has become of practical importance as the portion of on-chip interconnect resources dedicated to power distribution networks in high performance integrated circuits has greatly increased. The inductive characteristics of several types of gridded power distribution networks are described in this paper. The inductance extraction program FastHenry is used to evaluate the inductive properties of grid structured interconnect. In power distribution grids with alternating power and ground lines, the inductance is shown to vary linearly with grid length and inversely linearly with the number of lines in the grid. The inductance is also relatively constant with frequency in these grid structures. These properties permit the efficient estimation of the inductive characteristics of power distribution grids. To optimize the process of allocating on-chip metal resources, inductance/area/resistance tradeoffs in high speed performance distribution grids are explored. Two tradeoff scenarios in power grids with alternating power and ground lines are considered. 相似文献
95.
SB Mannheimer KA Sepkowitz M Stoeckle CR Friedman A Hafner LW Riley 《Canadian Metallurgical Quarterly》1997,1(4):319-325
The discovery of neuroendocrine differentiation in hormone-refractory prostatic adenocarcinoma has opened a potentially new therapeutic approach in this group of patients with a poor prognosis and few effective therapy modalities. Based on previous findings of increased uptake of 11C-5-hydroxytryptophan (11C-5-HTP) in neuroendocrine tumours using the PET technique, this tracer was applied in the study of 10 patients with metastatic hormone-refractory prostatic adenocarcinoma. In three patients, the study was repeated after treatment. An increased uptake of 11C-5-HTP was observed in all investigated skeletal lesions, although the magnitude of the uptake was moderate. The difference between the standard uptake values (SUV) in normal bone and metastatic lesions was significant (p < 0.001). A kinetic analysis of the uptake of 11C-5-HTP demonstrates an increase during the first minutes followed by a wash-out and a stabilization of the tissue/blood ratio at about 2. The Patlak plots demonstrated a gradual increase in the transport rate during the first 20 to 30 min, after which a constant level was observed. The SUV varied between patients and between lesions over time and treatment. The uptake of 11C-5-HTP discriminates metastatic lesions from normal bone and may thus aid in the diagnosis and, potentially, in treatment monitoring of metastatic hormone-refractory prostatic adenocarcinoma. Uptake kinetics are characterized by a wash-out and cannot alone be used as proof of neuroendocrine differentiation in hormone-refractory prostatic adenocarcinoma. 相似文献
96.
Rapport Lisa J.; Friedman Sara L.; Tzelepis Angela; Van Voorhis Amy 《Canadian Metallurgical Quarterly》2002,16(1):102
[Correction Notice: An erratum for this article was reported in Vol 16(3) of Neuropsychology (see record 2007-17085-001). On Page 102, in the byline and in the author note, and on page 109 in the Rapport et al. (2001) reference, Sara Friedman's middle initial incorrectly reads "L." Her correct middle initial is "R."] Emotional competence and deficits that may disrupt interpersonal interactions were evaluated in 28 adults with attention-deficit hyperactivity disorder (ADHD) and 28 demographically equivalent controls. Participants completed tasks assessing affect recognition and experienced emotional intensity. Adults with ADHD performed worse in affect recognition than did adults without the disorder; however, the impairment was unrelated to gross perceptual processes, fundamental abilities in facial recognition, or attentional aspects of affect perception. Moreover, intensity of experienced emotion moderated affect recognition: Among controls, experienced emotion facilitated affect recognition. Among adults with ADHD, who reported significantly greater intensity, experienced emotion was inversely related to affect recognition. Results are consistent with theories of ADHD as a deficit in behavioral inhibition; yet, results may merely reflect a constellation of deficits associated with the disorder. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
97.
Placement of Substrate Contacts to Minimize Substrate Noise in Mixed-Signal Integrated Circuits 总被引:1,自引:0,他引:1
Radu M. Secareanu Scott Warner Scott Seabridge Cathie Burke Thomas E. Watrobski Christopher Morton William Staub Thomas Tellier Eby G. Friedman 《Analog Integrated Circuits and Signal Processing》2001,28(3):253-264
The placement of substrate contacts in epi and non-epi technologies is analyzed in order to control and reduce the substrate noise amplitude and spreading. The choice of small or large substrate contacts or rings for each of the two major technologies is highlighted. Design guidelines for placing substrate contacts so as to improve the noise immunity of digital circuits in mixed-signal smart-power systems are also presented. 相似文献
98.
Irwin Friedman 《今日电子》2008,(10)
电子系统具有告警指示的能力已经成为所必须的技术指标之 在当今的电子设计中,声音报警已经成为基本的功能.无论是高音安全警报器,还是可以发出的嘀嘀声的条形码扫描器,这些产品已经成为了我们生活中的一部分. 相似文献
99.
Freeman Nicholas; Friedman Ronald S.; Bartholow Bruce D.; Wulfert Edelgard 《Canadian Metallurgical Quarterly》2010,18(2):135
Recent studies have suggested that exposure to rudimentary alcohol cues activates mental representations of alcohol expectancies in long-term memory, thereby promoting expectancy-consistent behavior changes. However, reliance in these previous studies on self-report measures raises the possibility that prior findings were an artifact of experimental demand. The present study was aimed at ruling out this alternative explanation by reinvestigating the effects of alcohol priming on nonconsumptive behavior using an implicit measure of social disinhibition. In three experiments, participants were exposed to either alcohol or control beverage images, then asked to type as quickly as possible the first word that came to mind in response to a series of provocative (e.g., feces) and neutral (e.g., chair) stimulus words. Participants’ response times were surreptitiously measured. Results revealed that participants exposed to images of alcohol, relative to control beverages, were faster to generate free associations to provocative, but not neutral, words, suggesting enhanced social disinhibition. This effect was limited to conditions of heightened evaluation, ruling out alternative explanations based on knowledge activation or arousal. Participants reported no suspicions regarding the connection between the image viewing and free association tasks nor any awareness that their response times had been collected. Results suggest that the behavioral effects of alcohol priming do not result from demand characteristics and offer the first evidence that exposure to rudimentary alcohol-related stimuli may suffice to influence social disinhibition in a manner akin to that expected to result from actual or placebo alcohol consumption. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
100.
This paper discusses the dangers of relying solely on TCP reliability when implementing dependable computing systems, even when those systems are designed to work over a LAN environment. The discussion includes a real-life example from our recent experiences in developing such a system. 相似文献