全文获取类型
收费全文 | 262篇 |
免费 | 14篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 93篇 |
金属工艺 | 2篇 |
机械仪表 | 4篇 |
建筑科学 | 6篇 |
能源动力 | 4篇 |
轻工业 | 53篇 |
水利工程 | 2篇 |
石油天然气 | 3篇 |
无线电 | 18篇 |
一般工业技术 | 36篇 |
冶金工业 | 35篇 |
原子能技术 | 1篇 |
自动化技术 | 19篇 |
出版年
2023年 | 3篇 |
2022年 | 18篇 |
2021年 | 19篇 |
2020年 | 4篇 |
2019年 | 8篇 |
2018年 | 4篇 |
2017年 | 7篇 |
2016年 | 16篇 |
2015年 | 6篇 |
2014年 | 6篇 |
2013年 | 13篇 |
2012年 | 12篇 |
2011年 | 8篇 |
2010年 | 14篇 |
2009年 | 11篇 |
2008年 | 11篇 |
2007年 | 10篇 |
2006年 | 12篇 |
2005年 | 10篇 |
2004年 | 5篇 |
2003年 | 9篇 |
2002年 | 7篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1996年 | 7篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1969年 | 1篇 |
1968年 | 3篇 |
1963年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有278条查询结果,搜索用时 15 毫秒
31.
Burke Jeffrey D.; Loeber Rolf; White Helene Raskin; Stouthamer-Loeber Magda; Pardini Dustin A. 《Canadian Metallurgical Quarterly》2007,116(2):249
The authors examined the prediction from inattention to tobacco use among 2 cohorts (ages 7 and 13) of a community sample followed to young adulthood. Changes in self-reported tobacco use were tested with marginal transitional regression models, using parent and teacher ratings of inattention, hyperactivity-impulsivity, and other psychopathology, along with other factors, as predictors. Inattention, but not hyperactivity-impulsivity, significantly predicted adolescent tobacco use and young adult daily tobacco use. Peer substance use, parental substance use, and conduct disorder also predicted increases in tobacco use. African American ethnicity was strongly protective against later tobacco use. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
32.
An easy procedure for the preparation of solutions containing certain types of reactive dye and their subsequent application on cotton is described. This procedure takes advantage of the expected high reactivity of these dyes, which have adjacent hydroxy and amino groups in the molecule, and strives to evade the problems usually associated with the preparation and application of such dyes in the solid form. Several factors that affect the colour strength of reactive dyeings thus obtained are investigated. Possible disadvantages when applying this procedure are discussed. 相似文献
33.
Keltner Dacher; Moffitt Terrie E.; Stouthamer-Loeber Magda 《Canadian Metallurgical Quarterly》1995,104(4):644
On the basis of the widespread belief that emotions underpin psychological adjustment, the authors tested 3 predicted relations between externalizing problems and anger, internalizing problems and fear and sadness, and the absence of externalizing problems and social–moral emotion (embarrassment). Seventy adolescent boys were classified into 1 of 4 comparison groups on the basis of teacher reports using a behavior problem checklist: internalizers, externalizers, mixed (both internalizers and externalizers), and nondisordered boys. The authors coded the facial expressions of emotion shown by the boys during a structured social interaction. Results supported the 3 hypotheses: (a) Externalizing adolescents showed increased facial expressions of anger, (b) on 1 measure internalizing adolescents showed increased facial expressions of fear, and (c) the absence of externalizing problems (or nondisordered classification) was related to increased displays of embarrassment. Discussion focused on the relations of these findings to hypotheses concerning the role of impulse control in antisocial behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
34.
35.
A. V. Bochkov A. V. Zagidulin É. P. Magda V. V. Mironenko G. S. Sofienko A. S. Podymako 《Technical Physics Letters》2006,32(10):843-844
The possibility of lasing in a YAP:Tm3+ crystal with 3F4 level of the Tm3+ ion directly pumped by narrowband radiation of a gas laser operating in the middle IR range has been studied. The efficiency of the pumped energy conversion into spontaneous emission on the 3F4-3H6 transition in the Tm3+ ion was within 65–75%. The efficiency of generation with respect to the absorbed pumping energy was ~4%. 相似文献
36.
Tamariz E Wan AC Pek YS Giordano M Hernández-Padrón G Varela-Echavarría A Velasco I Castaño VM 《Journal of materials science. Materials in medicine》2011,22(9):2097-2109
Chemotropic proteins guide neuronal projections to their final target during embryo development and are useful to guide axons
of neurons used in transplantation therapies. Site-specific delivery of the proteins however is needed for their application
in the brain to avoid degradation and pleiotropic affects. In the present study we report the use of Poly (ethylene glycol)-Silica
(PEG-Si) nanocomposite gel with thixotropic properties that make it injectable and suitable for delivery of the chemotropic
protein semaphorin 3A. PEG-Si gel forms a functional gradient of semaphorin that enhances axon outgrowth of dopaminergic neurons
from rat embryos or differentiated from stem cells in culture. It is not cytotoxic and its properties allowed its injection
into the striatum without inflammatory response in the short term. Long term implantation however led to an increase in macrophages
and glial cells. The inflammatory response could have resulted from non-degraded silica particles, as observed in biodegradation
assays. 相似文献
37.
Jozef Ková Jozef Tekel Magda Kurucová 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1987,184(2):96-100
Summary The method described is based on the biochemical detection of herbicides on a silica gel thin layer following their chromatographic separation. The detection reagent is a mixture of a homogenate of bean leaves (Phaseolus vulgaris) and of the redox indicator 2,6-dichloroindophenol. This chronometric determination of herbicide residues is based on the observation that dark blue inhibition zones appear on a pale yellow-green background during the exposure of the sprayed chromatoplates Silufol to light. The dark blue zones disappear again after a time, their lifetime is proportional to the amount of the herbicide in the zone.Because of the high selectivity and sensitivity of the biochemical detection this method does not require a multiple clean-up procedure, nor does it require sophisticated instrumentation. It equals gas chromatography in sensitivity and precision. The determination limit lies between 0.01 and 0.001 mg · kg–1, the average recovery rate is 85 to 90%.
Bestimmung der Herbicid-Rückstände in landwirtschaftlichen Produkten, in Lebensmitteln, im Boden und Wasser mit der chronometrischen Methode
Zusammenfassung Die Methode stützt sich auf einen biochemischen Nachweis der Herbicide auf einer Silicagel-Dünnschichtplatte nach ihrer chromatographischen Verteilung. Das Nachweisreagens ist eine Mischung aus einem Homogenat von Blättern der Bohnen (Phaseolus vulgaris, L.) und des Redoxindikators 2,6-Dichlorphenolindophenol. Die chronometrische Bestimmung der Herbicidrückstände gründet sich auf die Beobachtung, daß während der Lichtexposition der besprühten Dünnschichtplatte Silufol auf einem gelbgrünen Hintergrund dunkelblaue Inhibitionszoneu entstehen, welche nach einer bestimmten Zeit verschwinden. Die Haltbarkeitszeit der Zone ist der Menge des Herbicids in der Zone direkt proportionell.In Betracht der hohen Selektivität und Empfindlichkeit des biochemischen Nachweises benötigt die Methode keine komplizierte Reinigung der Extrakte und keine hochentwickelte Ausstattung des Labors mit Instrumenten. Die Empfindlichkeit und Genauigkeit der chronometrischen Methode ist gleich der der Gaschromatographie. Die Bestimmungsgrenze ist 0,01 bis 0,001 mg·kg–1, die Wiederfindung ist 85–90%.相似文献
38.
Sanberg Paul R.; Bunsey Michael D.; Giordano Magda; Norman Andrew B. 《Canadian Metallurgical Quarterly》1988,102(5):748
The typical catalepsy (CPSY) test consists of placing an animal in an unusual posture and recording the time taken to correct this posture. This time is regarded as an index of the intensity of CPSY. CPSY is a robust behavior, and the lack of standardization does not usually hinder its actual detection. However, the intensity of the cataleptic effect is influenced by minor methodological differences, and interpretation and comparison of results across laboratories are difficult. The behavioral CPSY test can use any of several different apparatus, including wire grids, parallel bars, platforms, or pegs, to situate the animals in unusual positions. The most common is the bar test (BT), and despite its wide use in psychopharmacological research, even parameters of this test are not standardized. The present article reviews parameters chosen by investigators that measure CPSY. The methodological issues of repeated testing, scaling of scores, apparatus, animal weight, maximal test duration, behavioral criteria, and other influences are discussed. A brief review of the neuropharmacological basis of CPSY is included. It is argued that a universal, standardized BT be adopted by researchers. New data on a novel automated BT in the Digiscan Activity Monitoring System is presented. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
39.
Do behavioral observation scales measure observation? 总被引:1,自引:0,他引:1
G. Latham and K. Wexley (see record 1980-02200-001) have claimed that behavioral observation scales (BOS) pose a simpler task for the rater than do either behaviorally anchored rating scales or graphic rating scales; with BOS, the rater need only observe and record behavior and need not make complex judgments about performance. Research on person memory suggests that recall for behaviors is structured by the same trait inferences and judgments that BOS are designed to avoid. In 2 experiments, 91 undergraduates rated videotaped lectures; data from the 1st experiment were used to construct BOS measuring clarity and speaking style. In the 2nd experiment, Ss used the BOS and a graphic rating scale to rate videotaped lectures in immediate and delayed rating conditions. As expected, the correlations between BOS ratings and judgmental ratings of performance were stronger when demands were placed on rater's recall. It is suggested that recall of behaviors is determined by the degree to which certain behaviors are representative of general judgments made about Ss being rated, and that BOS measure traitlike judgments rather than behavioral observation. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
40.
Magda Borhan El‐Arnaouty Ashraf Maher Abdel Ghaffar Ashraf Abdel Kareem Abdel Baky Sayed Ahmed Shama 《乙烯基与添加剂工艺杂志》2019,25(Z1):E35-E43
Synthesis of carboxymethyl cellulose‐g‐methacrylic acid/acrylamide Poly(CMC/MAAc:AAm) hydrogel was carried out using direct radiation copolymerization technique at ambient temperature. The gel (%) increased with increasing the content of AAm till level off at Poly(CMC/MAAc:AAm) (1/50:50 wt%) hydrogel and the swelling behavior found to be increased with increasing MAAc content in the hydrogel composition up to Poly(CMC/MAAc:AAm) (1/60:40 wt%). The grafting yield, grafting ratio, swelling behavior, and the thermal stability of Poly(CMC/MAAc:AAm) binary system are higher than those reported in our previous study by the same author which described the individual grafting of acrylamide (AAm) and methacrylic acid (MAAc) with different concentration onto carboxymethyl cellulose (CMC) using direct radiation grafting technique. The swelling kinetics and diffusion mechanism indicate that the water penetration obey non‐Fickian transport mechanism. The characterization of the prepared hydrogel was evaluated using Fourier transform infrared, X‐ray diffraction, thermogravimetric analysis, and scanning electron microscopy. The analyses by different analytical tools confirmed the successful grafting of both MAAc and AAm onto CMC. The adsorption capacity of Poly(CMC/MAAc:AAm) (1/60:40 wt%) hydrogel toward metal ions such as Cu+2 and Co+2, dyes such as acid blue dye and methyl green have been investigated. J. VINYL ADDIT. TECHNOL., 25:E35–E43, 2019. © 2017 Society of Plastics Engineers 相似文献