全文获取类型
收费全文 | 26787篇 |
免费 | 708篇 |
国内免费 | 33篇 |
专业分类
电工技术 | 329篇 |
综合类 | 14篇 |
化学工业 | 5929篇 |
金属工艺 | 520篇 |
机械仪表 | 464篇 |
建筑科学 | 1159篇 |
矿业工程 | 332篇 |
能源动力 | 651篇 |
轻工业 | 1725篇 |
水利工程 | 226篇 |
石油天然气 | 245篇 |
无线电 | 1711篇 |
一般工业技术 | 4093篇 |
冶金工业 | 6154篇 |
原子能技术 | 266篇 |
自动化技术 | 3710篇 |
出版年
2022年 | 246篇 |
2021年 | 411篇 |
2020年 | 266篇 |
2019年 | 346篇 |
2018年 | 422篇 |
2017年 | 369篇 |
2016年 | 485篇 |
2015年 | 391篇 |
2014年 | 614篇 |
2013年 | 1652篇 |
2012年 | 938篇 |
2011年 | 1205篇 |
2010年 | 923篇 |
2009年 | 974篇 |
2008年 | 1148篇 |
2007年 | 1063篇 |
2006年 | 974篇 |
2005年 | 883篇 |
2004年 | 745篇 |
2003年 | 711篇 |
2002年 | 707篇 |
2001年 | 486篇 |
2000年 | 391篇 |
1999年 | 447篇 |
1998年 | 444篇 |
1997年 | 428篇 |
1996年 | 475篇 |
1995年 | 443篇 |
1994年 | 452篇 |
1993年 | 437篇 |
1992年 | 431篇 |
1991年 | 271篇 |
1990年 | 410篇 |
1989年 | 387篇 |
1988年 | 337篇 |
1987年 | 404篇 |
1986年 | 349篇 |
1985年 | 442篇 |
1984年 | 467篇 |
1983年 | 398篇 |
1982年 | 375篇 |
1981年 | 297篇 |
1980年 | 298篇 |
1979年 | 357篇 |
1978年 | 299篇 |
1977年 | 238篇 |
1976年 | 217篇 |
1975年 | 245篇 |
1974年 | 217篇 |
1973年 | 225篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
King Abby C.; Taylor C. Barr; Haskell William L.; DeBusk Robert F. 《Canadian Metallurgical Quarterly》1989,8(3):305
Evaluated 120 healthy, sedentary, middle-aged adults randomly assigned to either a 6-mo home-based aerobic exercise training program or to an assessment-only control condition. Adherence across the 6-mo period by the exercise group was demonstrated by self-report and heart rate microprocessor methods to exceed 75%. A 14-item Likert rating scale was used to measure a variety of psychological variables. Significant between-groups differences favoring the exercise group were found on scale items closely associated with actual physical changes that occurred with exercise (satisfaction with shape/appearance, perceived fitness). (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
102.
Comments on R. L. Woolfolk and F. C. Richardson's (see record 1985-12614-001) discussion of the ideology of behavior therapy and their argument that behavior therapy cannot develop a conception of what might be appropriate goals of treatment. The present author contends that goals are as much a scientific question as are questions of technique. A scientific approach to the study of goal selection is presented that can be applied to any type of adjustment problem. (8 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
103.
104.
Relation between depressive symptoms and stressful life events in a sample of disadvantaged mothers.
The bidirectional relation between life events and self-reported depression was examined across a 1-year period. With Time 1 depression controlled, Time 2 stress accounted for an additional 10% of Time 2 depressive symptoms. Health-related stress, family violence, and financial stress at Time 2 predicted Time 2 depression after control for Time 1 depression. With Time 1 stress controlled, Time 2 depression accounted for 8% of the variance in Time 2 stress. Time 2 depression predicted Time 2 health-related stress, financial stress, household changes, spouse–partner stress, family violence stress, and substance abuse stress, controlling for each of these stressors at Time 1. The results describe a complex relation between stress and depression and suggest that the relation between stress and depression is moderated by the type of stress. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
105.
Emery Robert E.; Matthews Sheila G.; Kitzmann Katherine M. 《Canadian Metallurgical Quarterly》1994,62(1):124
A 1-yr follow-up study was conducted on families randomly assigned to settle custody disputes either in mediation or through adversary procedures. Consistent with Time 1 reports, at Time 2 fathers who mediated were substantially more satisfied than were fathers who litigated. Fathers who mediated also complied more with child support orders. Contrary to prediction, the greater satisfaction and compliance of fathers did not lead to increased satisfaction among mothers who mediated. In contrast to Time 1, at follow-up mothers who mediated were significantly less satisfied than were mothers who litigated, but selective attrition may account for these differences. The psychological adjustment of mothers and fathers was not significantly different between settlement groups at Time 2, but mothers in both groups reported less satisfaction with dispute settlement and less dysphoria at Time 2 than they had reported at Time 1. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
106.
Thompson Robert J.; Gil Karen M.; Keith Barbara R.; Gustafson Kathryn E.; George Linda K.; Kinney Thomas R. 《Canadian Metallurgical Quarterly》1994,62(4):856
Rates of poor psychological adjustment of children with sickle cell disease remained relatively constant over initial and follow-up assessment points. 50 children (aged 7–12 yrs) and their mothers completed the initial protocol. 30 children completed the follow-up plus 5 additional children and their mothers. These Ss were aged 7–24 yrs at follow-up. With initial levels of adjustment controlled, children's strategies for coping with pain accounted for a significant increment in child-reported symptoms and mother-reported internalizing behavior problems at follow-up beyond the contribution of illness and demographic parameters and follow-up interval. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
107.
Previous research on adaptation to visual-motor rearrangement suggests that the CNS represents accurately only 1 visual–motor mapping at a time. This idea was examined in 3 experiments where Ss tracked a moving target under repeated alternations between 2 initially interfering mappings (the "normal" mapping characteristic of computer input devices and a 108° rotation of the normal mapping). Alternation between the 2 mappings led to significant reduction in error under the rotated mapping and significant reduction in the adaptation aftereffect ordinarily caused by switching between mappings. Color as a discriminative cue, interference vs decay in adaptation aftereffect, and intermanual transfer were also examined. The results reveal a capacity for multiple concurrent visual–motor mappings, possibly controlled by a parametric process near the motor output stage of processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
108.
Lewinsohn Peter M.; Roberts Robert E.; Seeley John R.; Rohde Paul; Gotlib Ian H.; Hops Hyman 《Canadian Metallurgical Quarterly》1994,103(2):302
In a prospective study of adolescent depression, adolescents (N?=?1,508) were assessed at Time 1 and after 1 yr (Time 2) on psychosocial variables hypothesized to be associated with depression. Most psychosocial variables were associated with current (n?=?45) depression. Formerly depressed adolescents (n?=?217) continued to differ from never depressed controls on many of the psychosocial variables. Many of the depression-related measures also acted as risk factors for future depression (n?=?112), especially past depression, current other mental disorders, past suicide attempt, internalizing behavior problems, and physical symptoms. Young women were more likely to be, to become, and to have been depressed. Controlling for the psychosocial variables eliminated the gender difference for current and future but not for past depression. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
109.
Krueger Robert F.; Schmutte Pamela S.; Caspi Avshalom; Moffitt Terrie E.; Campbell Kathleen; Silva Phil A. 《Canadian Metallurgical Quarterly》1994,103(2):328
Is there a relationship between personality and criminal behavior? We addressed this question in a representative birth cohort of 862 male and female 18-yr-olds. Personality was assessed with the Multidimensional Personality Questionnaire (MPQ). The MPQ measures 10 relatively independent personality traits and was not designed to identify offenders. Delinquency was assessed via 3 data sources: self-reports, informant reports, and official records. Variable-centered analyses revealed that MPQ scales indexing negative emotionality and behavioral constraint were consistent predictors of delinquency across the 3 data sources. Person-centered analyses revealed that youths abstaining from delinquency were uniquely characterized by low interpersonal potency. Youths involved in extensive delinquency were uniquely characterized by feelings of alienation, lack of social closeness and risk taking. Advances in understanding criminal behavior can be made through research that places the personality-delinquency link in a developmental context. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
110.
F. L. Schmidt and J. E. Hunter (1989) critiqued the within-group interrater reliability statistic (rwg) described by L. R. James et al (1984). S. W. Kozlowski and K. Hattrup (1992) responded to the Schmidt and Hunter critique and argued that rwg is a suitable index of interrater agreement. This article focuses on the interpretation of rwg as a measure of agreement among judges' ratings of a single target. A new derivation of rwg is given that underscores this interpretation. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献