全文获取类型
收费全文 | 640篇 |
免费 | 27篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 72篇 |
金属工艺 | 8篇 |
机械仪表 | 9篇 |
建筑科学 | 55篇 |
矿业工程 | 2篇 |
能源动力 | 9篇 |
轻工业 | 100篇 |
水利工程 | 8篇 |
无线电 | 29篇 |
一般工业技术 | 90篇 |
冶金工业 | 190篇 |
自动化技术 | 92篇 |
出版年
2023年 | 7篇 |
2022年 | 15篇 |
2021年 | 14篇 |
2020年 | 19篇 |
2019年 | 14篇 |
2018年 | 28篇 |
2017年 | 15篇 |
2016年 | 19篇 |
2015年 | 12篇 |
2014年 | 23篇 |
2013年 | 44篇 |
2012年 | 32篇 |
2011年 | 51篇 |
2010年 | 30篇 |
2009年 | 29篇 |
2008年 | 45篇 |
2007年 | 31篇 |
2006年 | 38篇 |
2005年 | 24篇 |
2004年 | 24篇 |
2003年 | 19篇 |
2002年 | 23篇 |
2001年 | 10篇 |
2000年 | 8篇 |
1999年 | 9篇 |
1998年 | 19篇 |
1997年 | 14篇 |
1996年 | 6篇 |
1995年 | 6篇 |
1994年 | 6篇 |
1993年 | 5篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 5篇 |
1983年 | 1篇 |
1981年 | 3篇 |
1976年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有667条查询结果,搜索用时 0 毫秒
111.
Gordon Kate; Pasco Greg; McElduff Fiona; Wade Angie; Howlin Pat; Charman Tony 《Canadian Metallurgical Quarterly》2011,79(4):447
Objective: This article examines the form and function of spontaneous communication and outcome predictors in nonverbal children with autism following classroom-based intervention (Picture Exchange Communication System [PECS] training). Method: 84 children from 15 schools participated in a randomized controlled trial (RCT) of PECS (P. Howlin, R. K. Gordon, G. Pasco, A. Wade, & T. Charman, 2007). They were aged 4–10 years (73 boys). Primary outcome measure was naturalistic observation of communication in the classroom. Multilevel Poisson regression was used to test for intervention effects and outcome predictors. Results: Spontaneous communication using picture cards, speech, or both increased significantly following training (rate ratio [RR] =1.90, 95% CI [1.46, 2.48], p 相似文献
112.
Interventions designed to reduce heavy drinking among college students often contain suggestions for drinking control strategies. However, little is known about the relationship between the use of these strategies and alcohol consumption. The authors developed a measure of drinking control strategies and investigated its psychometric properties in a sample of 250 college drinkers. Strategies clustered into three factors: selective avoidance of heavy drinking activities and situations, strategies used while drinking, and alternatives to drinking. These three types of strategies were independently associated with alcohol use; however, the first and last types were negatively associated with alcohol consumption, whereas the second type was positively associated with alcohol use. The findings from this study suggest that the type of strategy recommended may be important when the goal is alcohol reduction. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
113.
Banerjee Robin; Yuill Nicola; Larson Christina; Easton Kate; Robinson Elizabeth; Rowley Martin 《Canadian Metallurgical Quarterly》2007,43(5):1084
Two experiments investigated children's implicit and explicit differentiation between beliefs about matters of fact and matters of opinion. In Experiment 1, 8- to 9-year-olds' (n = 88) explicit understanding of the subjectivity of opinions was found to be limited, but their conformity to others' judgments on a matter of opinion was considerably lower than their conformity to others' views regarding an ambiguous fact. In Experiment 2, children aged 6, 8, or 10 years (n = 81) were asked to make judgments either about ambiguous matters of fact or about matters of opinion and then heard an opposing judgment from an expert. All age groups conformed to the opposing judgments on factual matters more than they did to the experts' views on matters of opinion. However, only the oldest children explicitly recognized that opinions are subjective and cannot be "wrong." Implications of these results for models of children's reasoning about epistemic states are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
114.
M van Beurden N van der Vange AJ de Craen SP Tjong-A-Hung FJ ten Kate J ter Schegget FB Lammes 《Canadian Metallurgical Quarterly》1997,104(3):320-324
Expression of chicken and rat liver bifunctional enzyme, 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase, in Escherichia coli encountered two common problems: the chicken enzyme was liable to proteolysis and the rat enzyme was prone to form inclusion bodies. Reducing the rate of protein synthesis by lowering either growth temperature or isopropyl-beta-D-thiogalactopyranoside (IPTG) concentration alleviated these two problems. Growth at 22 degrees C was optimum for expression of both enzymes. The optimum range of IPTG concentration for expression was 0.1-1 microM for the chicken liver bifunctional enzyme and 10 microM for rat liver enzyme. The components of growth medium also influenced the production. Compared with Luria-Bertani medium, an enriched medium-tryptone-phosphate medium-tripled the production of the active enzymes. Addition of glucose (0.2%) doubled the expression level of active chicken liver enzyme, but reduced the production of active rat liver enzyme to half the maximal level, while the phosphate in tryptone-phosphate medium had no effect on the production of the two enzymes. 相似文献
115.
This prospective study tested whether early menarche partially accounts for the increases in depression, eating pathology, substance abuse, and comorbid psychopathology that occur among adolescent girls, with structured interview data from a community sample (N?=?496). Early menarche (prior to 11.6 years) was associated with elevated depression, substance abuse, and "any" disorder but did not confer increased risk for anorexia nervosa, bulimia nervosa, or binge eating disorder. Although there was significant comorbidity across all three classes of pathology, early menarche was associated only with comorbid depression and substance abuse. Results provide partial support for the assertion that early menarche is a general risk factor for psychopathology among adolescent girls but suggest that this risk may not apply to certain disorders and that the effects are modest in size. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
116.
117.
The development and capabilities of a prototype expert system that provides real-time spacecraft system analysis and command generation are described. At present, ESSOC (Expert System for Satellite Orbit Control) is capable of performing the stationkeeping maneuver for a geostationary satellite. ESSOC guides the operator through the stationkeeping operation by recommending appropriate commands that reflect both the changing spacecraft condition and previous procedural action. Information regarding satellite status is stored in a knowledge base internal to the expert system. This knowledge base is continuously updated with processed spacecraft telemetry. Information on the procedural structure is encoded in production rules. The independence of the procedural rules from each other, and from the knowledge base, makes the system easy to maintain and expand. Particular attention is directed to distinctive features of the ESSOC system and its development, namely, the structured methods of knowledge acquisition, and the design and performance-enhancing techniques that enable ESSOC to operate in a real-time environment. 相似文献
118.
Recent work (e.g., S. Harkins; see PA, Vol 75:20027; K. Szymanski and Harkins; see PA, Vol 75:7410) has suggested that social loafing occurs because participants' outputs cannot be evaluated by the experimenter, by the coactors, or by the participants themselves. This analysis had focused on the output of the individual, but in loafing research, participants work together to produce a group product. However, in this prior work participants have been unable to make anything of this group product, because no standard of comparison has been made available. Several recent formulations (e.g., G. Goethals and J. Darley, 1987) have suggested that the potential for group evaluation could motivate performance. Testing this hypothesis in 2 experiments, 1 using an optimizing task and the other a maximizing task, we found that providing a standard that allowed the "group" to evaluate its performance eliminated the loafing effect. The implications of these findings for current theories of group evaluation are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
119.
Rice Catherine; Koinis Daphne; Sullivan Kate; Tager-Flusberg Helen; Winner Ellen 《Canadian Metallurgical Quarterly》1997,33(1):54
68 3-yr-olds received a standard appearance–reality task along with either a trick task, in which the appearance question was placed in the context of a deceptive game, or a reduced information processing task, in which a dual object (e.g., a sponge-rock) was presented along with an object that matched the dual object's identity (a sponge) and one that matched the dual object's appearance (a rock). Children were more likely to pass either the trick or reduced information processing task and fail the standard than the reverse. Thus, 3-yr-olds can grasp the distinction between appearance and reality (a) when their goal is to trick someone, which may prime them to think about the other's mental state, and (b) when they do not need to hold conflicting object identities in mind at the same time. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
120.
Does interpersonal psychotherapy protect women from depression in the face of stressful life events?
Harkness Kate L.; Frank Ellen; Anderson Barbara; Houck Patricia R.; Luther James; Kupfer David J. 《Canadian Metallurgical Quarterly》2002,70(4):908
The present study compared the role of life events in predicting time to index episode onset under conditions of no or variable treatment versus the role of life events in predicting time to recurrence during maintenance interpersonal psychotherapy (IPT). Eighty-three women with recurrent major depression participated in acute IPT treatment followed by 2 years of maintenance IPT. Life events were assessed using contextual interview and rating methods. Cox regression survival analyses indicated that, although severe life events were significantly associated with time to index episode onset, there was little evidence of an association between events experienced during maintenance treatment and time to recurrence. These results provide evidence that IPT may decrease the potency of life events in provoking recurrence. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献