全文获取类型
收费全文 | 885篇 |
免费 | 32篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 179篇 |
金属工艺 | 10篇 |
机械仪表 | 8篇 |
建筑科学 | 36篇 |
矿业工程 | 9篇 |
能源动力 | 27篇 |
轻工业 | 145篇 |
水利工程 | 10篇 |
石油天然气 | 7篇 |
无线电 | 39篇 |
一般工业技术 | 112篇 |
冶金工业 | 255篇 |
原子能技术 | 4篇 |
自动化技术 | 74篇 |
出版年
2023年 | 6篇 |
2022年 | 21篇 |
2021年 | 23篇 |
2020年 | 13篇 |
2019年 | 20篇 |
2018年 | 11篇 |
2017年 | 18篇 |
2016年 | 20篇 |
2015年 | 16篇 |
2014年 | 27篇 |
2013年 | 43篇 |
2012年 | 32篇 |
2011年 | 49篇 |
2010年 | 35篇 |
2009年 | 56篇 |
2008年 | 45篇 |
2007年 | 31篇 |
2006年 | 28篇 |
2005年 | 33篇 |
2004年 | 31篇 |
2003年 | 38篇 |
2002年 | 26篇 |
2001年 | 17篇 |
2000年 | 19篇 |
1999年 | 13篇 |
1998年 | 6篇 |
1997年 | 19篇 |
1996年 | 12篇 |
1995年 | 14篇 |
1994年 | 14篇 |
1993年 | 20篇 |
1992年 | 16篇 |
1990年 | 7篇 |
1989年 | 15篇 |
1988年 | 13篇 |
1987年 | 11篇 |
1986年 | 8篇 |
1985年 | 10篇 |
1984年 | 4篇 |
1983年 | 7篇 |
1982年 | 8篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1978年 | 9篇 |
1977年 | 5篇 |
1976年 | 7篇 |
1975年 | 5篇 |
1974年 | 3篇 |
1964年 | 3篇 |
排序方式: 共有917条查询结果,搜索用时 0 毫秒
101.
S.K. Martha B. Hariprakash S.A. Gaffoor A.K. Shukla 《Journal of Applied Electrochemistry》2006,36(6):711-722
Positive- and negative-limited lead-acid cells with conventional and polyaniline (PANI)-coated negative plates were assembled and tested at varying discharge rates. The cells with PANI-coated negative plates exhibit lower impedance in relation to conventional cells and sustain higher discharge-rates with lesser loss in capacity during prolonged charge–discharge cycling as compared to conventional cells. It is suggested that PANI-coated negative plates are beneficial in designing lead-acid batteries operating at partial-state-of-charge. 相似文献
102.
Martha Salcudean Roderick I. L. Guthrie 《Metallurgical and Materials Transactions B》1978,9(2):181-189
The fluid flow generated during the course of tapping operations from Basic Oxygen Furnaces was analyzed. Mathematical models of the filling process were developed, and their predictions checked with experimental values obtained using a one-tenth scale model of the ladle. Reasonable agreement was achieved. Based on the full scale predictions, it is suggested that the magnitude of flow velocities are technologically significant in terms of their effect on ferro-alloy immersion times and recoveries. 相似文献
103.
Goldin-Meadow Susan; Alibali Martha W.; Church R. Breckinridge 《Canadian Metallurgical Quarterly》1993,100(2):279
Thoughts conveyed through gesture often differ from thoughts conveyed through speech. A model of the sources and consequences of such gesture–speech mismatches and their role during transitional periods in the acquisition of concepts is proposed. The model makes 2 major claims: (1) The transitional state is the source of gesture–speech mismatch. In gesture–speech mismatch, 2 beliefs are simultaneously expressed on the same problem, one in gesture and another in speech. This simultaneous activation of multiple beliefs characterizes the transitional knowledge state and creates gesture–speech mismatch. (2) Gesture–speech mismatch signals to the social world that a child is in a transitional state and is ready to learn. The child's spontaneous gestures index the zone of proximal development, thus providing a mechanism by which adults can calibrate their input to that child's level of understanding. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
104.
Kobasigawa Akira; Lacasse Martha A.; MacDonald Vincent A. 《Canadian Metallurgical Quarterly》1988,20(1):50
Examined the development of text search strategies in 144 4th, 6th, and 8th graders who were assigned to reading booklets with or without headings embedded in the reading material. Both younger and older Ss demonstrated evidence of efficient use of headings as locational aids when explicitly instructed on how to use them, and spontaneous use of headings as a search strategy was observed in half of the 4th and 6th graders and in most of the 8th graders. Ss at all levels read faster when asked to search for a specific fact than when asked to read the story line by line, indicating their awareness of when to skim. Findings suggest that by the 4th grade, children may have the cognitive skills to benefit from headings but may use these skills only in structured situations. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
105.
The ability of persons faking posttraumatic stress disorder (PTSD) or closed-head injury (CHI) to respond consistently across serial testings on the Minnesota Multiphasic Personality Inventory—2 (MMPI-2; J. Butcher, W. Dahlstrom, J. Graham, A. Tellegen, & B. Kaemmer, 1989) was investigated. Results showed that individuals faking PTSD obtained 2-week test–retest reliability scores comparable to individuals completing the MMPI-2 with standard instructions; individuals faking CHI obtained reliability coefficients significantly lower than individuals faking PTSD. A 3?×?2 (Response Style?×?Time) analysis of variance indicated that individuals faking a disorder obtained significantly elevated scores on validity scales sensitive to overreporting; no main effect for time was found. Results suggest that test-takers faking specific disorders can describe symptoms consistently on repeated testing and that type of disorder may affect temporal response consistency. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
106.
Two hyperbaric studies tested detrimental effects of 188-ft sea water gauge (fswg) air pressure. In each experiment, 8 males aged 22–32 yrs, qualified for hyperbaric exposures, executed single-task controls of a choice reaction time (RT) task and a pursuit tracking task, as well as their dual-task combinations. All tasks were tested 0, 10, and 188 fswg. Exp I was designed to measure the effects of nitrogen narcosis on 2 successive weekly dives. No improvement specific to the 188 fswg depth was found on the 2nd dive. It is concluded that the prior exposure did not result in measurable adaptation to narcosis. At 188 fswg, the rate of information transmission in the choice RT task was slowed and tracking error increased. Dual-task requirements resulted in poorer tracking but left choice RT performance unaffected. In Exp II, half of the Ss stopped at 19 fswg before proceeding to depth. They showed a decrement in performance at 188 fswg equal to, or greater than, that found for the remaining Ss, who used the standard procedure of descending to depth directly. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
107.
Tested hypotheses derived from social psychological and feminist theory that acceptance of rape myths can be predicted from attitudes such as sex role stereotyping, adversarial sexual beliefs, sexual conservatism, and acceptance of interpersonal violence. Personality characteristics, background characteristics, and personal exposure to rape, rape victims, and rapists are other factors used in predictions. Results from regression analysis of interview data from 598 randomly selected adults indicate that the higher the sex role stereotyping, adversarial sexual beliefs, and acceptance of interpersonal violence, the greater an S's acceptance of rape myths. In addition, younger and better educated Ss revealed fewer stereotypic, adversarial, and proviolence attitudes and less rape myth acceptance. Implications for understanding and changing this cultural orientation toward sexual assault are discussed. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
108.
Francisco Javier Castillo-Yáñez Ramón Pacheco-Aguilar Fernando Luís García-Carreño María de los Ángeles Navarrete-Del Toro Martha Félix López 《Food chemistry》2006,99(2):252-259
Chymotrypsin was isolated from the viscera of Monterey sardine by ammonium sulphate fractionation, gel filtration, and ionic exchange chromatography. The approximate molecular weight was 26,000 and its isoelectric point was about 5. Identity as chymotrypsin was established by its catalytic specificity for amide or ester bonds on the synthetic substrates succinyl-l-ala-ala-pro-l-pheilalanine-p-nitroanilide and benzoyl-l-tyrosine-ethyl-ester, showing esterase activity 3.2-fold higher than amidase. It was inhibited by phenylmethylsulfonyl-fluoride and soybean trypsin inhibitor, partly inhibited by the specific chymotrypsin inhibitor N-toluenesulfonyl-l-phenylalanine chloromethyl-ketone, but not inhibited by EDTA or Benzamidine. Chymotrypsin showed its maximum activity at pH 8.0 and 50 °C for the hydrolysis of SAAPNA. The Michaelis–Menten constant was 0.074 mM with a catalysis constant of 18.6 seg−1, and catalytic efficiency of 252 seg−1 mM−1. Results indicated that Monterey sardine chymotrypsin is a good catalyst and could be used as a biotechnological tool in food processing and using sardine industry wastes as a material for production of fine reagents. 相似文献
109.
Garo J. Derderian James D. Barrie Kenneth A. Aitchison Paul M. Adams Martha L. Mecartney 《Journal of the American Ceramic Society》1994,77(3):820-828
Epitaxial (110) orthorhombic KNbO3 thin films were prepared using alkoxide solutions. Single-phase films were produced with stoichiometric sols while slight variations in stoichiometry (52/48 Nb/K or 48/52 Nb/K) created residual second phases. Nucleation and growth of KNbO3 , as a function of process conditions were monitored by observing the KNbO3 rosettes produced from niobium-rich solutions. Methanolic solutions produced films with the highest rosette density and the highest amount of KNbO3 . Hydrolysis of the sol aided the crystallization of the KNbO3 phase but also promoted the formation of second phases. Hydrolysis at 0°C reduced second-phase formation. 相似文献
110.
Vellutino Frank R.; Scanlon Donna M.; Sipay Edward R.; Small Sheila G.; Pratt Alice; Chen RuSan; Denckla Martha B. 《Canadian Metallurgical Quarterly》1996,88(4):601
Reading impaired first graders were given daily tutoring as a "first cut" diagnostic to aid in distinguishing between reading difficulties caused by basic cognitive deficits and those caused by experiential deficits. Reading achievement in most of these children was found to be within or above the average range after one semester of remediation. Children who were difficult to remediate performed below both children who were readily remediated and normal readers on kindergarten and first-grade tests evaluating phonological skills, but not on tests evaluating visual, semantic and syntactic skills. The results are consistent with convergent findings from previous research suggesting that reading problems in some poor readers may be caused primarily by phonological deficits. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献