全文获取类型
收费全文 | 331篇 |
免费 | 22篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 11篇 |
化学工业 | 102篇 |
金属工艺 | 4篇 |
机械仪表 | 4篇 |
建筑科学 | 17篇 |
能源动力 | 2篇 |
轻工业 | 51篇 |
水利工程 | 5篇 |
无线电 | 23篇 |
一般工业技术 | 56篇 |
冶金工业 | 52篇 |
原子能技术 | 1篇 |
自动化技术 | 26篇 |
出版年
2023年 | 18篇 |
2022年 | 23篇 |
2021年 | 15篇 |
2020年 | 11篇 |
2019年 | 13篇 |
2018年 | 6篇 |
2017年 | 7篇 |
2016年 | 11篇 |
2015年 | 8篇 |
2014年 | 17篇 |
2013年 | 13篇 |
2012年 | 14篇 |
2011年 | 18篇 |
2010年 | 10篇 |
2009年 | 15篇 |
2008年 | 26篇 |
2007年 | 13篇 |
2006年 | 12篇 |
2005年 | 9篇 |
2004年 | 10篇 |
2003年 | 7篇 |
2002年 | 4篇 |
2001年 | 5篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1989年 | 4篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 6篇 |
1984年 | 4篇 |
1982年 | 2篇 |
1974年 | 2篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1967年 | 1篇 |
1934年 | 1篇 |
1932年 | 1篇 |
1931年 | 1篇 |
1930年 | 3篇 |
1929年 | 1篇 |
1928年 | 2篇 |
1927年 | 1篇 |
1900年 | 1篇 |
排序方式: 共有354条查询结果,搜索用时 15 毫秒
21.
22.
23.
24.
To examine whether primary-citation indexing can be taken as an unbiased representation of all-author indexing, we compared
the cited first-author counts (straight counts) with the cited all-author counts (complete counts)in two psychological journals
over two publication years. Although rather high correlations were found between straight counts and complete counts, correlations
differ with journals of the same discipline, with different publication years of the same journal, and according to seniority
of cited authors. No effect of alphabetical name ordering was found. Results are discussed against the background of the possible
use of weighting procedures for all-author indexing.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
25.
Memorializes B. H. Fox, a research scientist internationally known for his work on the epidemiology and etiology of cancer. Fox was instrumental in establishing a new field of research best described as biopsychosocial cancer epidemiology. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
26.
Kain J Galván M Taibo M Corvalán C Lera L Uauy R 《Archivos latinoamericanos de nutrición》2010,60(2):155-159
Because the results of the nutritional status released by Chilean institutions which collect anthropometric data on their population under control, show different increments in the prevalence of obesity between preschoolers and children in 1st grade, we decided to verify the real magnitude of this increase. This study is based on a longitudinal investigation which began in 2006 and included 1100, three-year old children, which we evaluated when they were 4, 5 and 6 y. The nutritional status was determined according to BMI Z and WHO References 2006/2007. The information was also used to determine the concordance between the anthropometric data collected on first graders by teachers from public schools in 2009 (JUNAEB data set) and the same children assessed in parallel by INTA (INTA data set). The sample included 474, six-year olds. No differences were found between the average BMI Z and HAZ of the two data sets, and the degree of concordance between the BMI Z's was good (rho = 0.73), however there were differences in the nutritional status, since the prevalence of low weight was significantly greater when assessed with JUNAEB's data (9.5% vs. 3.6% ), while that for obesity was lower with INTA's data, 17.5% vs. 19.2% (not significantly different). At 4 and 5 y, obesity prevalence of the children was 13.3% and 15.7% respectively (INTA's data). Considering the observed nutritional trajectory, it is likely that the rise in obesity between 4 and 6 y of age, was 4 percentage points and not 6, as was determined with INTA's data. 相似文献
27.
Lydia Toscano Gisela MonteroMargarita Stoytcheva Héctor CampbellAlejandro Lambert 《Biomass & bioenergy》2011,35(1):26-31
Oil derived fuels constituted a main energy source during the last fifty years, although their high price limited their accessibility. Prospective studies indicated that economic and environmental problems promoted biodiesel production using biomass and residues like animal fat, along with meat and bones, among others. The regional inventory of the available fat in meat industry, as well as the estimation of the biodiesel potential production demonstrated that the biodiesel generated from animal fat, combined with diesel from oil in a 2% biodiesel blend could power 25% of the trucks and passenger vehicles registered in 2007 in Baja California, Mexico. 相似文献
28.
Longitudinal stability of temperamental exuberance and social–emotional outcomes in early childhood.
Degnan Kathryn A.; Hane Amie Ashley; Henderson Heather A.; Moas Olga Lydia; Reeb-Sutherland Bethany C.; Fox Nathan A. 《Canadian Metallurgical Quarterly》2011,47(3):765
The goals of the current study were to investigate the stability of temperamental exuberance across infancy and toddlerhood and to examine the associations between exuberance and social–emotional outcomes in early childhood. The sample consisted of 291 4-month-olds followed at 9, 24, and 36 months and again at 5 years of age. Behavioral measures of exuberance were collected at 9, 24, and 36 months. At 36 months, frontal electroencephalogram (EEG) asymmetry was assessed. At 5 years, maternal reports of temperament and behavior problems were collected, as were observational measures of social behavior during an interaction with an unfamiliar peer in the laboratory. Latent profile analysis revealed a high, stable exuberance profile that was associated with greater ratings of 5-year externalizing behavior and surgency, as well as observed disruptive behavior and social competence with unfamiliar peers. These associations were particularly true for children who displayed left frontal EEG asymmetry. Multiple factors supported an approach bias for exuberant temperament but did not differentiate between adaptive and maladaptive social–emotional outcomes at 5 years of age. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
29.
Decheng Meng Lydia Francis Ipsita Roy Aldo R. Boccaccini 《Journal of Applied Electrochemistry》2011,41(8):919-923
Protein adsorption is the first step involved in establishing a suitable integration between a biomaterial and host tissue.
It is therefore of highest interest to know the electric charge of proteins present in the relevant medium to be able to predict
the behaviour of cells on given surfaces. In this study, electrophoretic deposition (EPD) was used as a simple method to identify
the charge of proteins present in biological medium. In the model experiment carried out here, EPD was conducted using a biological
medium containing 10% fetal calf serum (FCS) and the charge of the protein was determined by examining the migration of the
protein in the EPD cell under a certain applied voltage. In addition, the suitability of EPD of proteins to deliver tailored
surfaces for enhanced bioactivity or for controlled deposition of protein films on metallic surfaces was explored. 相似文献
30.
Ricardo Acosta Ortiz María Lydia Berlanga Duarte Amy Grace Savage Gómez Marco Sangermano Aída E García Valdez 《Polymer International》2010,59(5):680-685
Shrinkage that takes place during polymerizations induces internal stress in polymeric materials generating a series of problems like poor adhesion to substrates and delamination in coatings or microcracks and microvoids in composites. Some additives like spiro orthocarbonates can reduce or eliminate this shrinkage. This paper deals with the synthesis of novel diol spiro orthocarbonates (DIOL SOCs) and their effect as anti‐shrinkage additives in the photopolymerization of the monomer 3,4‐epoxycyclohexyl‐3′, 4′‐epoxycyclohexanecarboxylate. It was found that increasing the concentration of the DIOL SOCs resulted in higher conversion of the monomer due to the presence of hydroxyl groups. The viscoelastic properties of the polymer products were also measured. It was observed that at 5 mol% of the mixture of DIOL SOCs there was an increase in the storage modulus due to the crosslinking produced by the bifunctional SOCs. However, at higher concentrations, a decrease in the storage modulus was observed. The level of shrinkage using the DIOL SOCs at 20 mol% was reduced by 45% when compared to the case without any additive. DIOL SOCs can be easily prepared by reacting glycerol with tetraethylorthocarbonate. These additives reduced significantly the level of shrinkage of the polyether derived from the diepoxycyclohexane monomer. Copyright © 2010 Society of Chemical Industry 相似文献