全文获取类型
收费全文 | 2742篇 |
免费 | 104篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 12篇 |
化学工业 | 666篇 |
金属工艺 | 26篇 |
机械仪表 | 24篇 |
建筑科学 | 148篇 |
矿业工程 | 5篇 |
能源动力 | 53篇 |
轻工业 | 510篇 |
水利工程 | 20篇 |
石油天然气 | 6篇 |
无线电 | 108篇 |
一般工业技术 | 422篇 |
冶金工业 | 587篇 |
原子能技术 | 7篇 |
自动化技术 | 254篇 |
出版年
2023年 | 20篇 |
2022年 | 49篇 |
2021年 | 83篇 |
2020年 | 45篇 |
2019年 | 39篇 |
2018年 | 61篇 |
2017年 | 50篇 |
2016年 | 62篇 |
2015年 | 47篇 |
2014年 | 70篇 |
2013年 | 171篇 |
2012年 | 176篇 |
2011年 | 187篇 |
2010年 | 166篇 |
2009年 | 147篇 |
2008年 | 159篇 |
2007年 | 155篇 |
2006年 | 108篇 |
2005年 | 122篇 |
2004年 | 93篇 |
2003年 | 98篇 |
2002年 | 89篇 |
2001年 | 48篇 |
2000年 | 37篇 |
1999年 | 46篇 |
1998年 | 42篇 |
1997年 | 54篇 |
1996年 | 52篇 |
1995年 | 34篇 |
1994年 | 32篇 |
1993年 | 26篇 |
1992年 | 29篇 |
1991年 | 17篇 |
1990年 | 27篇 |
1989年 | 22篇 |
1988年 | 14篇 |
1987年 | 14篇 |
1986年 | 19篇 |
1985年 | 17篇 |
1984年 | 16篇 |
1983年 | 13篇 |
1982年 | 14篇 |
1980年 | 10篇 |
1979年 | 8篇 |
1978年 | 7篇 |
1977年 | 10篇 |
1976年 | 6篇 |
1975年 | 5篇 |
1973年 | 4篇 |
1948年 | 3篇 |
排序方式: 共有2848条查询结果,搜索用时 15 毫秒
21.
Tucker Joan S.; Friedman Howard S.; Tsai Catherine M.; Martin Leslie R. 《Canadian Metallurgical Quarterly》1995,10(1):3
Models of the relations between contact with pets and better health are examined in an archival prospective study using data derived from the longitudinal study initiated by Terman in 1921 (current N?=?343 men, 300 women) . In survival analyses of documented longevity, playing with pets in 1977 (M age?=?67 years) was not associated with mortality risk through 1991 for the total sample nor for those who were unmarried or those who were less satisfied with their human relationships. Playing with pets was not associated with health-prone attributes or healthy behaviors such as personality, social ties, education, and smoking. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
22.
Hitchcock Janice M.; Sananes Catherine B.; Davis Michael 《Canadian Metallurgical Quarterly》1989,103(3):509
Bilateral electrolytic lesions of the central, but not the lateral, nucleus of the amgydala blocked shock sensitization of startle (the increase in startle produced by presentation of ten 0.6-mA footshocks in rapid succession). Lesions of the central nucleus also decreased reactivity to shock (jumping and flinching) during shock presentation. However, this decrease in reactivity cannot account for the blockade of shock sensitization, because when a higher shock intensity (1.0 mA) was used, producing equivalent reactivity to that of controls at 0.6 mA, central nucleus lesions still blocked shock sensitization. Moreover, lesions of the caudal part of the ventral amygdalofugal pathway, which carries central nucleus efferents to the startle reflex pathway, also blocked shock sensitization. It is hypothesized that shock activates the central nucleus of the amygdala, which increases startle through modulation of the startle pathway. Activation of the amygdala by shock may be the unconditioned response relevant for fear conditioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
23.
24.
Foreman Nigel; Save Etienne; Thinus-Blanc Catherine; Buhot Marie-Christine 《Canadian Metallurgical Quarterly》1992,106(3):529
When hooded rats with bilateral lesions of Krieg's Area 7 (parietal cortex) were trained to locomote toward visual targets in a runway, they ran less accurately than did controls, although unilaterals ran accurately. When flashing lights were presented unexpectedly during their run, bilateral parietals were less disrupted than were controls, but they failed to show total neglect. Unilateral parietals turned toward distracters on either side but turned preferentially toward distracters contralateral to the intact hemisphere, particularly when distracters occurred bilaterally and simultaneously. Effects due to the omission of expected distracters were similar in parietals and controls. Rat parietal cortex is not essential for the redirection of attention to stimuli notable for their unexpected presence or absence, but parietal cortex may resolve interhemispheric competition. Results suggest a homology between parietal cortex in rat and primate. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
25.
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
26.
Kaslow Nadine J.; Rubin Nancy J.; Forrest Linda; Elman Nancy S.; Van Horne Barbara A.; Jacobs Sue C.; Huprich Steven K.; Benton Sherry A.; Pantesco Victor F.; Dollinger Stephen J.; Grus Catherine L.; Behnke Stephen H.; Miller David S. Shen; Shealy Craig N.; Mintz Laurie B.; Schwartz-Mette Rebecca; Van Sickle Kristi; Thorn Beverly E. 《Canadian Metallurgical Quarterly》2007,38(5):479
Working collaboratively, psychologist educators and trainers at the doctoral, internship, and postdoctoral levels; credentialers; practitioners; and students offer 8 proposals for psychologists to consider in recognizing, assessing, and intervening with problems of professional competence in students and practicing professionals. In the proposals, the authors address the following topics: definitions and categories; preparing the system; self-assessment; remediation; diversity; communication across various levels of the system; confidentiality; and ethical, regulatory, and legal underpinnings. They also propose future directions for the assessment of problems in professional competence in both students and practicing psychologists. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
27.
Wilcox Teresa; Woods Rebecca; Chapa Catherine; McCurry Sarah 《Canadian Metallurgical Quarterly》2007,43(2):479
Recent research indicates that by 4.5 months, infants use shape and size information as the basis for individuating objects but that it is not until 11.5 months that they use color information for this purpose. The present experiments investigated the extent to which infants' sensitivity to color information could be increased through select experiences. Five experiments were conducted with 10.5- and 9.5-month-olds. The results revealed that multimodal (visual and tactile), but not unimodal (visual only), exploration of the objects prior to the individuation task increased 10.5-month-olds' sensitivity to color differences. These results suggest that multisensory experience with objects facilitates infants' use of color information when individuating objects. In contrast, 9.5-month-olds did not benefit from the multisensory procedure; possible explanations for this finding are explored. Together, these results reveal how an everyday experience--combined visual and tactile exploration of objects--can promote infants' use of color information as the basis for individuating objects. More broadly, these results shed light on the nature of infants' object representations and the cognitive mechanisms that support infants' changing sensitivity to color differences. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
28.
Theorists have predicted that repetition blindness (RB) should be absent for nonwords because they do not activate preexisting mental types. The authors hypothesized that RB would be observed for nonwords because RB can occur at a sublexical level. Four experiments showed that RB is observed for word-nonword pairs (noon noof), orthographically similar nonwords (glome glame), and identical repetitions (plass plass). More RB was found for words than for nonwords. Prior researchers may have failed to find RB for nonwords because display conditions that allow 2 words to be reliably encoded are insufficient for nonwords, or because observers coped with low ability to encode nonwords by using guessing strategies that do not require creating a mental type or tokenizing it. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
29.
Zakaria Chajar Michel Primet Hélène Praliaud Michèle Chevrier Catherine Gauthier Frédéric Mathis 《Catalysis Letters》1994,28(1):33-40
The role of nitrogen dioxide in the selective reduction of NO by propane over a Cu-MFI zeolite is investigated. NO2 and NO reductions were carried out under similar conditions of reaction. In the presence of oxygen, the reduction of NO by C3H8 does not differ significantly from that of NO2. In the absence of oxygen, the reduction of NO2 by propane occurs with a partial decomposition of the nitric dioxide molecule. Such a decomposition leads to the formation of oxygen, which is responsible for the increase in catalytic activity by comparison with the same reaction performed with NO. NO2 formed and released in the gas phase during the reduction of NO by propane in the presence of oxygen does not play a predominant role in the catalytic process. 相似文献
30.
Cooney CM 《Environmental science & technology》1996,30(9):387A
Society. 相似文献