全文获取类型
收费全文 | 646篇 |
免费 | 10篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 141篇 |
金属工艺 | 2篇 |
机械仪表 | 3篇 |
建筑科学 | 27篇 |
能源动力 | 1篇 |
轻工业 | 51篇 |
水利工程 | 3篇 |
无线电 | 17篇 |
一般工业技术 | 74篇 |
冶金工业 | 296篇 |
自动化技术 | 41篇 |
出版年
2022年 | 6篇 |
2021年 | 7篇 |
2018年 | 6篇 |
2014年 | 8篇 |
2013年 | 14篇 |
2012年 | 11篇 |
2011年 | 32篇 |
2010年 | 18篇 |
2009年 | 17篇 |
2008年 | 24篇 |
2007年 | 37篇 |
2006年 | 24篇 |
2005年 | 22篇 |
2004年 | 17篇 |
2003年 | 12篇 |
2002年 | 17篇 |
2001年 | 18篇 |
2000年 | 13篇 |
1999年 | 8篇 |
1998年 | 11篇 |
1997年 | 16篇 |
1996年 | 17篇 |
1995年 | 10篇 |
1994年 | 12篇 |
1993年 | 16篇 |
1992年 | 11篇 |
1991年 | 5篇 |
1990年 | 12篇 |
1989年 | 14篇 |
1988年 | 13篇 |
1987年 | 11篇 |
1986年 | 13篇 |
1985年 | 9篇 |
1984年 | 9篇 |
1983年 | 9篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1979年 | 5篇 |
1978年 | 9篇 |
1977年 | 8篇 |
1976年 | 9篇 |
1975年 | 5篇 |
1974年 | 7篇 |
1973年 | 9篇 |
1964年 | 4篇 |
1963年 | 9篇 |
1962年 | 11篇 |
1961年 | 9篇 |
1960年 | 12篇 |
1959年 | 11篇 |
排序方式: 共有657条查询结果,搜索用时 15 毫秒
71.
This study examines longitudinal correlates of coparental and family group-level dynamics during infancy. Thirty-seven couples observed at play with their 8-11-month-old infants (15 boys, 22 girls) rated their child's internalizing and externalizing symptoms, and their own coparenting behavior 3 years later. Teachers also rated child behavior at the 3-year follow-up. Several significant relationships emerged between observed family process (high hostility-competitiveness, low family harmony, and high parenting discrepancies in the triad) at Time 1, and subsequent reports of child and coparenting behavior at Time 2. Larger parenting discrepancies at Time 1 predicted greater child anxiety as rated by teachers; greater hostility-competitiveness and lower harmony forecast higher child aggression. Time 1 family process continued to predict Time 2 aggression even after controlling for individual and marital functioning. Several links were also found between distressed family process and later parental reports of negative coparenting behavior. These parental reports of coparenting also explained unique variance in concurrent child behavior ratings. The significance of coparenting as a distinct family construct is discussed. 相似文献
72.
The cooling power of aqueous solutions of polyvinylpyrrolidone are studied with a silver standard sample by using two apparatuses quench with injection and quench with agitation. The dependences of the cooling rates at each temperature on polymer concentration and solution viscosity are established and empirical laws of variation are given. 相似文献
73.
Two brief laboratory tasks measuring delay of gratification in different ways were administered to 116 4-yr-old children. Personality data were available on these children separately at ages 3, 4, 7, and 11 yrs in the form of California Child Q-Set ratings by independent sets of teachers and examiners. The 2 delay-of-gratification measures were used to generate a more broadly based index of delay of gratification, and this index was correlated with the personality ratings available at the 4 ages. Boys who delayed gratification tended to be described as deliberative, attentive, reasonable, reserved, cooperative, and able to modulate motivational and emotional impulse. Boys who did not delay gratification, by contrast, were irritable, restless, aggressive, and generally not self-controlled. Girls who delayed gratification were consistently described as intelligent, resourceful, and competent. Girls who did not delay tended to go to pieces under stress; to be victimized by other children; and to be easily offended, sulky, and whiny. Findings are interpreted in terms of the constructs of ego control and ego resiliency and the differential socialization of the sexes. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
74.
Families with school-age children were interviewed 3 times, at 6-mo intervals (winter-summer-winter), to test whether summer brings discontinuity in family processes. Longitudinal patterns of parent–child involvement, parental monitoring, and children's involvement in activities were examined for 125 families in 3 groups: DDD (consistently dual-earner), SSS (consistently single-earner), and DSD (dual-earner at Times 1 and 3, single-earner over the summer). In SSS and DSD families, mothers became more involved with their children over the summer, and the division of parenting became more traditional (with mothers more involved than fathers), whereas DDD families maintained a more egalitarian division of parenting. DSD fathers monitored their children less over the summer, whereas DDD fathers became more knowledgeable about their children's activities. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
75.
Hypothesized that college women's locus of control orientations would be related to their role expectations, with women with an external locus of control having lower aspirations, more conservative sex-role ideologies, and less involvement in career planning than women with an internal locus of control. 116 female college juniors and seniors completed a career expectation scale, the Adult Nowicki-Strickland Internal-External Control Scale (ANSIE), and an index of sympathy for women's liberation ideology. Regression analyses using ANSIE scores as the predictor variable supported the hypotheses. Compared to Ss with internal orientations, Ss with external orientations expected to have less commitment to their careers, to work for a smaller portion of their lives, and to feel more discomfort due to violating sex-role stereotypes. In addition, Ss with a more external orientation reported less career planning activity, less positive feelings about their future careers, and more conservative views on women's liberation ideology. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
76.
77.
78.
Edward T. McHale 《Fire Technology》1974,10(1):15-24
Consider the possibilities of a habitable atmosphere in which ignition cannot occur. The author reports on some investigations
aimed at this very objective.
Note: Presented at the 77th Annual Meeting of the National Fire Protection Association in St. Louis, MO on May 16, 1973. 相似文献
79.
Direct chemical sensing in liquid environments using polymer-guided shear horizontal surface acoustic wave sensor platforms on 36 degrees rotated Y-cut LiTaO3 is investigated. Design considerations for optimizing these devices for liquid-phase detection are systematically explored. Two different sensor geometries are experimentally and theoretically analyzed. Dual delay line devices are used with a reference line coated with poly (methyl methacrylate) (PMMA) and a sensing line coated with a chemically sensitive polymer, which acts as both a guiding layer and a sensing layer or with a PMMA waveguide and a chemically sensitive polymer. Results show the three-layer model provides higher sensitivity than the four-layer model. Contributions from mass loading and coating viscoelasticity changes to the sensor response are evaluated, taking into account the added mass, swelling, and plasticization. Chemically sensitive polymers are investigated in the detection of low concentrations (1-60 ppm) of toluene, ethylbenzene, and xylenes in water. A low-ppb level detection limit is estimated from the present experimental measurements. Sensor properties are investigated by varying the sensor geometries, coating thickness combinations, coating properties, and curing temperature for operation in liquid environments. Partition coefficients for polymer-aqueous analyte pairs are used to explain the observed trend in sensitivity for the polymers PMMA, poly(isobutylene), poly(epichlorohydrin), and poly(ethyl acrylate) used in this work. 相似文献
80.