全文获取类型
收费全文 | 199篇 |
免费 | 11篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 40篇 |
金属工艺 | 2篇 |
机械仪表 | 2篇 |
建筑科学 | 6篇 |
能源动力 | 5篇 |
轻工业 | 53篇 |
水利工程 | 1篇 |
无线电 | 7篇 |
一般工业技术 | 17篇 |
冶金工业 | 50篇 |
原子能技术 | 1篇 |
自动化技术 | 25篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 12篇 |
2020年 | 3篇 |
2019年 | 6篇 |
2018年 | 3篇 |
2017年 | 8篇 |
2016年 | 7篇 |
2015年 | 7篇 |
2014年 | 6篇 |
2013年 | 8篇 |
2012年 | 12篇 |
2011年 | 16篇 |
2010年 | 5篇 |
2009年 | 6篇 |
2008年 | 9篇 |
2007年 | 6篇 |
2006年 | 10篇 |
2005年 | 8篇 |
2004年 | 5篇 |
2003年 | 5篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 6篇 |
1998年 | 10篇 |
1997年 | 7篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1993年 | 5篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1985年 | 2篇 |
1983年 | 4篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1969年 | 2篇 |
1962年 | 1篇 |
排序方式: 共有210条查询结果,搜索用时 421 毫秒
21.
Lila Raj Dahal Deepak SainjuN.J. Podraza S. MarsillacR.W. Collins 《Thin solid films》2011,519(9):2682-2687
Real time spectroscopic ellipsometry (RTSE) has been applied to analyze the optical characteristics of Ag/ZnO and Al/ZnO interfaces used in back-reflector (BR) structures for thin film silicon photovoltaics. The structures explored here are relevant to the substrate/BR/Si:H(n-i-p) solar cell configuration and consist of opaque Ag or Al films having controllable thicknesses of microscopic surface roughness, followed by a ZnO layer up to ~ 3000 Å thick. The thicknesses of the final surface roughness layers on both Ag and Al have been varied by adjusting magnetron sputtering conditions in order to study the effects of metal film roughness on interface formation and interface optical properties. The primary interface loss mechanisms in reflection are found to be dissipation via absorption through localized plasmon modes for Ag/ZnO and through intraband and interband transitions intrinsic to metallic Al for Al/ZnO. 相似文献
22.
Dominique Bertrand Marc Lila Vincent Furtoss Paul Robert Gerard Downey 《Journal of the science of food and agriculture》1987,41(4):299-307
Application of principal component regression (PCR) was proposed for the development of a prediction equation of forage composition by near infra-red spectroscopy. PCR involves two steps: (a) the creation of new synthetic variables by principal component analysis (PCA) of spectral data, and (b) multiple linear regression with these new variables. Results obtained by this procedure have been compared with those generated by the conventional application of multiple linear regression (MLR) on spectral data. The comparison used the determination of protein content and in vitro dry matter digestibility (IVDMD) in 345 samples of lucerne forages. For protein determination, results of both procedures were quite similar (correlation coefficients: 0.978 and 0.980; standard errors of calibration: 0.86 and 0.84% DM; standard errors of prediction: 0.81 and 0.80% DM respectively for MLR and PCR prediction equations). The same was observed for IVDMD determination (correlation coefficients: 0.942 and 0.951; standard errors of calibration: 1.89 and 1.71% DM; standard errors of prediction: 2.22 and 2.22% DM, respectively). A large number of PCA variables were necessary for an accurate prediction of both constituents. The influence of the number of regression terms introduced in the PCR equation has been studied. The criterion for stopping the introduction of new terms in PCR did not seem as critical as in MLR. 相似文献
23.
Rita Prosmiti Pablo Villarreal Gerardo Delgado-Barrio 《Israel journal of chemistry》2003,43(3-4):279-286
The ground-state potential surface of the Ar-ClF complex is determined by restricted coupled-cluster with single and double excitations and a noniterative perturbation treatment of triple excitation (RCCSD(T)) calculations, using augmented correlation consistent basis sets supplemented with an additional set of midbond functions. Three local minima are found for the Ar-ClF, which correspond to linear Ar-Cl-F and Ar-F-Cl configurations and a near T-shaped structure. The well depths and the equilibrium distances are 283.62 cm−1 at 3.84 Å and 128.96 cm−1 at 4.31 Å for the linear ones and 173.13 cm−1 at 3.58 Å for the one at θ = 107.5°. Bound-state calculations are carried out and the linear Ar-Cl-F structure is found to be the most stable one, in accordance with the experiment. Dissociation energies, intermolecular distances, and vibrational frequencies are computed and compared with available experimental data. 相似文献
24.
25.
L Alvarez MY Rios C Esquivel MI Chávez G Delgado MI Aguilar ML Villarreal V Navarro 《Canadian Metallurgical Quarterly》1998,61(6):767-770
Two new cytotoxic isoflavans, (3S)-7-hydroxy-2',3',4',5', 8-pentamethoxyisoflavan (1) and (3S)-3',7-dihydroxy-2',4',5', 8-tetramethoxyisoflavan (2), were isolated from the bark and trunks of Eysenhardtia polystachya (Leguminosae), together with the known constituents stigmasterol, isoduartin, cuneatin, 7-hydroxy-2',4', 5'-trimethoxyisoflavone, and 3,4-dimethoxy-8, 9-(methylenedioxy)pterocarpan. The structures of 1 and 2 were elucidated on the basis of spectroscopic methods. The antimicrobial, cytotoxic, and insecticidal potential of some of these compounds were evaluated. The isoflavans 1, 2, and isoduartin (2', 7-dihydroxy-3',4',8-trimethoxyisoflavan) displayed moderate cytotoxic activity against KB cell lines. 相似文献
26.
Investigated whether toddlers could remember the left and right sides of a symmetrical array. 64 22-35 mo old children learned to find a reward under 1 box of a 2- or a 9-box array. Two generalization conditions were introduced: The array was moved to new positions on 1 side of the S, or the S moved 180° to a new side of the table. To prevent visual tracking of the correct box, the array was kept covered except when the S responded. Ss were able to identify the correct side of the array after various spatial displacements; however, good performance appeared primarily for the 9-box array. Three conclusions are drawn: (a) The use of 2-choice tasks limits the study of spatial cognition; (b) a developmental shift from an egocentric to an allocentric framework may be more apparent than real; and (c) an analysis of the cognitive demands of left-right tasks provides a better basis for understanding performance than the assumption that discriminations along the horizontal axis are difficult to make and remember. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
27.
28.
Asakura L Cazita PM Harada LM Nunes VS Berti JA Salerno AG Ketelhuth DF Gidlund M Oliveira HC Quintão EC 《Lipids》2006,41(7):655-662
The possibility that soy protein containing isoflavones influences the development of experimental atherosclerosis has been
investigated in ovariectomized mice heterozygous for the human CETP transgene and for the LDL-receptor null allele (LDLr+/− CETP+/−). After ovariectomy at 8 wk of age they were fed a fat/cholesterol-rich diet for 19 wk and divided into three experimental
groups: dietary unmodified soy protein containing isoflavones (mg/g of diet), either at low-dose (Iso Low, 0.272, n=25), or at high-dose (Iso High, 0.535, n=28); and the atherogenic diet containing an isoflavone-depleted alcohol-washed soy protein as a control group (n=28). Aortic root lipid-stained lesion area (mean μm2×103±SD) did not differ among Iso Low (12.3±9.9), Iso High (7.4±6.4), and controls (10.7±12.8). Autoantibody titers against plasma
oxidized LDL did not differ among the experimental groups. Using the control mice as the reference value (100%), in vitro mouse peritoneal macrophage uptake of labeled acetylated LDL-cholesterol was lower in the Iso High (68%) than in the Iso
Low (85%) group. The in vitro percent removal by exogenous HDL of labeled unesterified cholesterol from macrophages previously enriched with human [4-14C]-cholesteryl oleate acetylated LDL was enhanced in the Iso High group (50%). In spite of these in vitro potentially antiatherogenic actions, soy protein containing isoflavones did not modify the average size of lipid-stained
area in the aortic root. 相似文献
29.
Usefulness of a set of simple in vitro tests for the screening and identification of probiotic candidate strains for dairy use 总被引:1,自引:0,他引:1
Gabriel Vinderola Barbara Capellini Fernanda Villarreal Viviana Surez Andrea Quiberoni Jorge Reinheimer 《LWT》2008,41(9):1678-1688
A set of simple in vitro tests (identification by species-specific PCR, genetic diversity, phage sensitivity, growth and viability in milk, resistance to salts and flavor compounds, bacterial interactions, tolerance to simulated gastric juice and bile, bile salts deconjugation, hydrophobicity and β-galactosidase and antibacterial activities), that can be carried out in almost every laboratory of microbiology, mainly in developing countries where there is often limited access to sophisticated techniques, allowed us to identify, among 19 intestinal human isolates, a potential candidate for new probiotic dairy foods for the local market. Lactobacillus gasseri LgF37/1 performed well in the culture media used for the enumeration of probiotic bacteria in argentinian dairy products. This strain showed also high tolerance to the technological challenges assessed, bile salts resistance, the capacity to produce bacteriocin-like metabolites, to inhibit pathogenic bacteria, to deconjugate bile salts and high hydrophobicity. Further in vivo research should be carried out with this strain before claiming probiotic properties for it. However, the use of a set of simple in vitro techniques proved to be important to determine which strains should undergo future and more complex studies. 相似文献
30.
Mohammad S.K. Bhuyan Seunghyun Ko Maria G. Villarreal Elliott J. Straus Lee James Jose M. Castro 《Polymer Engineering and Science》2019,59(6):1158-1166
In‐mold coating (IMC) is a thermosetting liquid applied to compression molded sheet molding compound (SMC) exterior automotive or truck body panels as an environmentally friendly primer to improve surface quality and make the part conductive for subsequent electrostatic painting. The IMC is injected onto the surface of the SMC then cures and bonds to provide a smooth conductive and protective surface. In IMC as in many other reactive polymer processes, to have short cycle time while maintaining adequate flow time and pot life is required. This allows enough time to fill the mold before solidification. In this study, the effect of inhibitor (p‐benzoquinone), initiator (t‐butyl peroxybenzoate), and mold temperature on the flow and cure time of IMC materials has been experimentally investigated using differential scanning calorimeter. A cure model is developed based on experiments to predict inhibition and cure time. A multiple criteria optimization method was employed to identify the setting parameters of the controllable process variables that provide the best compromise (Pareto frontier [PF]) between flow and cure time. The analysis shows that simultaneous addition of initiator and inhibitor allows the molding to be performed at a higher temperature, which moves the PF toward the ideal location. Hence, minimizes the cure time and maximizes the flow time simultaneously. POLYM. ENG. SCI., 59:1158–1166 2019. © 2019 Society of Plastics Engineers 相似文献