全文获取类型
收费全文 | 1931篇 |
免费 | 61篇 |
国内免费 | 8篇 |
专业分类
电工技术 | 18篇 |
综合类 | 11篇 |
化学工业 | 152篇 |
金属工艺 | 15篇 |
机械仪表 | 29篇 |
建筑科学 | 40篇 |
矿业工程 | 8篇 |
能源动力 | 37篇 |
轻工业 | 62篇 |
水利工程 | 46篇 |
石油天然气 | 5篇 |
无线电 | 224篇 |
一般工业技术 | 145篇 |
冶金工业 | 984篇 |
原子能技术 | 18篇 |
自动化技术 | 206篇 |
出版年
2022年 | 9篇 |
2021年 | 18篇 |
2020年 | 14篇 |
2019年 | 16篇 |
2018年 | 14篇 |
2017年 | 17篇 |
2016年 | 16篇 |
2015年 | 26篇 |
2014年 | 31篇 |
2013年 | 70篇 |
2012年 | 36篇 |
2011年 | 46篇 |
2010年 | 33篇 |
2009年 | 39篇 |
2008年 | 38篇 |
2007年 | 47篇 |
2006年 | 53篇 |
2005年 | 73篇 |
2004年 | 40篇 |
2003年 | 26篇 |
2002年 | 48篇 |
2001年 | 27篇 |
2000年 | 19篇 |
1999年 | 46篇 |
1998年 | 258篇 |
1997年 | 165篇 |
1996年 | 113篇 |
1995年 | 74篇 |
1994年 | 80篇 |
1993年 | 64篇 |
1992年 | 19篇 |
1991年 | 22篇 |
1990年 | 17篇 |
1989年 | 18篇 |
1988年 | 24篇 |
1987年 | 16篇 |
1986年 | 30篇 |
1985年 | 33篇 |
1984年 | 14篇 |
1983年 | 16篇 |
1982年 | 17篇 |
1981年 | 11篇 |
1980年 | 15篇 |
1979年 | 8篇 |
1978年 | 8篇 |
1977年 | 36篇 |
1976年 | 66篇 |
1974年 | 7篇 |
1973年 | 7篇 |
1970年 | 6篇 |
排序方式: 共有2000条查询结果,搜索用时 31 毫秒
1.
Myers Nicholas D.; Payment Craig A.; Feltz Deborah L. 《Canadian Metallurgical Quarterly》2004,8(3):182
This study examined reciprocal relationships between collective efficacy and team performance over a season of competition in women's intercollegiate ice hockey within weekends where the opponent was constant for 2 games. Collective efficacy beliefs within 12 teams were assessed prior to both games for at least 7 weekends. Team performance indexes produced an overall measure of performance for each game. The average influence of Saturday collective efficacy on Saturday performance was moderate and positive after controlling for Friday performance. The average influence of Friday performance on Saturday collective efficacy was small and positive after removing the influence of Friday collective efficacy from Friday performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
2.
3.
Albrecht Jason E.; O'Brien Edward J.; Mason Robert A.; Myers Jerome L. 《Canadian Metallurgical Quarterly》1995,21(2):364
An implicit assumption of several causal reasoning models is that readers adopt the goals of a narrative's protagonist during text comprehension. In apparent violation of this assumption, readers participating in Experiment 1 of the present study drew inferences relevant to a protagonist's goal even when that goal was already satisfied from the perspective of the protagonist. In Experiments 2 and 3, participants were explicitly asked to view the text situation from the point of view of the protagonist. In this case, the goals of the reader and the protagonist should be the same. In these experiments, participants focused on the goals of the protagonist only when those goals had not been satisfied from the perspective of the protagonist. These results are discussed in terms of reader- and character-based perspectives and in terms of text characteristics that cue perspective taking. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
4.
5.
6.
In the present investigation, the process model developed in Part I has been applied to evaluate the microstructure and strength
evolution during active brazing of ceramics. As a starting point, reaction-layer growth is assumed to occur isothermally with
no restrictions in the supply of reactive element. Different kinds of diagrams are then constructed to show how specific process
variables (e.g. the heating and cooling period, the limiting layer thickness, and the diffusion mechanism) affect the growth
kinetics. It is concluded that the key to improved joint properties lies in control of the reaction-layer thickness through
optimization of the brazing conditions, and an illustration of this is given.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
7.
JE Myers T Mieczkowski J Perel D Abbondanza TB Cooper JJ Mann 《Canadian Metallurgical Quarterly》1994,35(2):112-120
Serotonergic responsivity was assessed in 20 psychiatric patients by the prolactin response to a fenfluramine challenge test. During the fenfluramine challenge 6 of 20 patients (30%) spontaneously reported psychopathologic reactions that included: increased anxiety/agitation, psychotic symptoms, illusions, mood elevation, and anergia. The time of peak behavioral symptoms (2.5 +/- 0.8 hrs) corresponded closely to the time of peak increase in prolactin levels (3.0 +/- 1.1 hr). Abnormal behavioral responders had statistically significant greater increases in prolactin 1 to 4 hr after fenfluramine when compared to normal responders. Patients who developed an abnormal psychopathologic response to fenfluramine were characterized by higher levels of anxiety and agitation at the time of admission to the hospital but otherwise were not distinguishable on the basis of severity of other psychiatric symptoms. This study suggests that increased serotonergic transmission may trigger anxiety, psychosis, and mood elevation in specific vulnerable individuals, whereas other patients with similar psychiatric illnesses are not affected. 相似文献
8.
Myers Jerome L.; O'Brien Edward J.; Albrecht Jason E.; Mason Robert A. 《Canadian Metallurgical Quarterly》1994,20(4):876
Previous research demonstrated a contradiction effect: Although text currently being processed was locally coherent, readers were aware of inconsistencies between a protagonist's actions and characteristics of the protagonists that were described earlier in the text and subsequently backgrounded. In the present experiments, not only the critical characteristics but also the protagonist were backgrounded. When the protagonist was reintroduced into the narrative in the context of carrying out an inconsistent action, the contradiction effect again occurred. In Exps 1–3, we examined the effects of several variables on the onset of the effect. In Exp 4, we presented probes at various points in the passage with results that supported the conclusion that the critical characteristics had been backgrounded before the sentence that contradicted them. Results are discussed in terms of several recent models in which currently active representational elements serve as retrieval cues for other inactive, but highly related, elements. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
9.
KL Gatford TP Fletcher IJ Clarke PC Owens KJ Quinn PE Walton PA Grant BJ Hosking AR Egan EN Ponnampalam 《Canadian Metallurgical Quarterly》1996,74(6):1314-1325
The effects of sex and age on patterns of circulating somatotropin (ST) concentration and plasma IGF-I, IGF-II, insulin, and IGF binding protein-3 (IGFBP-3) were studied in ram, wether, and ewe lambs (n = 7 or 8) sampled at mean ages of 81 (I1) and 158 d (I2). Between 81 and 158 d of age, rams grew more rapidly than wethers (P < .01), and wethers grew more rapidly than ewes (P < .01). The sex differences in growth were reflected in empty body weight at slaughter: rams > wethers > ewes (P < .05). Mean plasma ST concentrations, ST pulse amplitude, and integrated plasma ST concentrations were greater (P < .05) in rams than in ewes at I1 and I2. Characteristics of the ST plasma profile in wethers were generally intermediate between those of rams and ewes. The interpulse interval was greater in ewes than in wethers at I2. The IGF-I and IGFBP-3 concentrations were greater in rams than in ewes at both sampling times. Plasma IGF-II was greater in ewes than in rams at I2. Mean plasma ST was approximately two thirds less at I2 than at I1 regardless of sex. Mean plasma ST and IGF-I at both ages were positively correlated with growth. Mean plasma ST at I2 was negatively correlated with fatness at slaughter. Sex and age significantly affected patterns of circulating ST and concentrations of IGF-I and IGFBP-3 in prepubertal growing lambs, under conditions for which growth rates and composition were also sexually dimorphic. 相似文献
10.
Myers Mark G.; MacPherson Laura; McCarthy Denis M.; Brown Sandra A. 《Canadian Metallurgical Quarterly》2003,15(2):163
The goal of the present studies was to construct and validate a short form of the 50-item Smoking Consequences Questionnaire (SCQ; T. H. Brandon & T. B. Baker, 1991), a measure of smoking outcome expectancies. In Study 1, a 21-item short form (S-SCQ) was derived from a sample of 107 young adults previously treated for substance abuse. In Study 2, the measure was cross-validated on 125 adolescents in treatment for substance abuse. Confirmatory factor analyses revealed good model fit and factorial invariance for the 4 S-SCQ subscales across both samples. Validation analyses on each sample found that subscale scores generally correlated significantly with smoking-related variables. The present studies provide initial evidence for the utility of the S-SCQ when used with young adults and adolescents. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献