全文获取类型
收费全文 | 2869篇 |
免费 | 216篇 |
国内免费 | 87篇 |
专业分类
电工技术 | 239篇 |
综合类 | 283篇 |
化学工业 | 203篇 |
金属工艺 | 79篇 |
机械仪表 | 490篇 |
建筑科学 | 178篇 |
矿业工程 | 122篇 |
能源动力 | 14篇 |
轻工业 | 763篇 |
水利工程 | 39篇 |
石油天然气 | 31篇 |
武器工业 | 14篇 |
无线电 | 84篇 |
一般工业技术 | 139篇 |
冶金工业 | 177篇 |
原子能技术 | 3篇 |
自动化技术 | 314篇 |
出版年
2024年 | 12篇 |
2023年 | 53篇 |
2022年 | 70篇 |
2021年 | 111篇 |
2020年 | 92篇 |
2019年 | 77篇 |
2018年 | 69篇 |
2017年 | 62篇 |
2016年 | 57篇 |
2015年 | 122篇 |
2014年 | 178篇 |
2013年 | 146篇 |
2012年 | 240篇 |
2011年 | 207篇 |
2010年 | 140篇 |
2009年 | 136篇 |
2008年 | 134篇 |
2007年 | 183篇 |
2006年 | 160篇 |
2005年 | 163篇 |
2004年 | 109篇 |
2003年 | 115篇 |
2002年 | 59篇 |
2001年 | 74篇 |
2000年 | 75篇 |
1999年 | 51篇 |
1998年 | 38篇 |
1997年 | 34篇 |
1996年 | 32篇 |
1995年 | 27篇 |
1994年 | 21篇 |
1993年 | 14篇 |
1992年 | 8篇 |
1991年 | 10篇 |
1990年 | 7篇 |
1989年 | 12篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1978年 | 3篇 |
1965年 | 3篇 |
1964年 | 4篇 |
1961年 | 4篇 |
1956年 | 2篇 |
1955年 | 2篇 |
排序方式: 共有3172条查询结果,搜索用时 15 毫秒
11.
The current study examined psychological and physical health outcomes of the written disclosure paradigm and the hypothesis that the principles of therapeutic exposure account for the beneficial effects of the paradigm. Participants were randomly assigned to either a written disclosure condition or a control condition. Reactivity to the writing sessions was examined using both subjective and physiological measures. Measures of psychological and physical health were completed before and 1 month after the sessions. Participants assigned to the disclosure condition reported fewer psychological and physical symptoms at follow-up compared with control participants, though reductions were clinically significant for only 1 outcome measure. Physiological activation to the 1st disclosure session was associated with reduced psychological symptoms at follow-up for disclosure participants. Subjective reports of emotional responding corresponded with physiological reactivity. Implications of these findings are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
12.
求解电缆自感系数的一个佯谬 总被引:1,自引:0,他引:1
何贤美 《安徽工业大学学报》2002,19(1):79-81
用求自感系数的两个常用公式求解实心电缆自感系数时,如果不注意对公式中Φm及I的正确理解,将会得到不一致的“佯谬”结果。本文通过将实心电缆等效为许多细线圈的方法,用2种公式求解得到了一致的结果。 相似文献
13.
韩伟 《北京建筑工程学院学报》1991,(1):101-108
本文提出了空间连杆机构的构件组合法,并讨论了此方法在刚体导向中的应用。本文还给出了实现刚体导向用的数学模型及计算实例。 相似文献
14.
Liew Jeffrey; Eisenberg Nancy; Losoya Sandra H.; Fabes Richard A.; Guthrie Ivanna K.; Murphy Bridget C. 《Canadian Metallurgical Quarterly》2003,17(4):584
Relations of heart rate and skin conductance reactions to mildly evocative empathy-inducing slides with socioemotional functioning were examined for 154 children (mean age = 9 years, 5 months). In addition, maternal expressivity was tested as a moderator of these relations. Parents and teachers rated children's socioemotional functioning, and a behavioral measure of children's regulation was obtained. Boys who exhibited higher skin conductance and higher heart rate to slides depicting negative emotions were better regulated, less emotionally intense, and better adjusted than their peers. Furthermore, boys' regulation and adjustment were positively related to such physiological responding to negative slides if maternal negative expressivity was relatively low or moderate, but not high. Fewer findings were obtained for girls or for positive slides. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
15.
Higher testosterone levels are related to assertiveness and dominance. Given the relevance of those behavioral correlates to spouses' daily transactions, links between testosterone levels and marital interaction were explored among 92 newlywed couples. Marital problem-solving and social support transactions were assessed, and saliva was collected and assayed for testosterone. Whether marital behavior was related to husbands' and wives' testosterone levels was examined. The link between spouses' testosterone and their behavior was contingent on the partner's testosterone levels. Husbands exhibited more adaptive problem-solving behaviors and social support provision when husbands and wives were concordant for lower testosterone levels. In contrast, wives exhibited more adaptive support provision when spouses had discordant testosterone levels such that wives had higher levels and husbands had lower levels. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
16.
Hypnosis has been demonstrated to reduce analogue pain, and studies on the mechanisms of laboratory pain reduction have provided useful applications to clinical populations. Studies showing central nervous system activity during hypnotic procedures offer preliminary information concerning possible physiological mechanisms of hypnotic analgesia. Randomized controlled studies with clinical populations indicate that hypnosis has a reliable and significant impact on acute procedural pain and chronic pain conditions, Methodological issues of this body of research are discussed, as are methods to better integrate hypnosis into comprehensive pain treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
17.
基于模糊匹配的平面连杆机构反求设计研究 总被引:1,自引:0,他引:1
对平面连杆机构曲线进行了分析,提出了用一组特征参数来描述连杆曲线,建立了连杆曲线图谱库,并将模糊论应用于连杆机构的曲线匹配,从而获取所求的机构参数.最后给出了应用实例,证实了该方法的可行性与有效性. 相似文献
18.
已知铰链四杆机构的3组对应转角和机架的长度,绘出四杆机构的示意图,并在屏幕上显示各杆的长度和机构的类型。 相似文献
19.
20.
Three consumer products (a television set, a personal computer and a typewriter), all considered portable by their respective manufacturers, were evaluated experimentally for portability. Products were not considered portable if the physical and subjective workloads resulting from carrying them over specified distances were excessive. Twenty-two males and six females participated in the experimental investigation and carried the three products for distances of 45·72, 91·44. 137·16 and 182·88 m. Their pulse and ratings of perceived exertion (RPE) of the arms and whole body were recorded and used as measures of physical and perceived workloads. Both physiological and subjective responses to carrying products were significantly influenced by the type of product and carrying distance, regardless of the gender of the person performing the carrying. The results of this study and the design guidelines provided in the literature for one-handed and two-handed carrying tasks led to the conclusion that, of the three products, only the television set could be considered portable. 相似文献