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91.
92.
Using the finite-difference time-domain method, we show that the plasmons of a nanostar result from hybridization of plasmons of the core and tips of the nanoparticle. The nanostar core serves as a nanoscale antenna, dramatically increasing the excitation cross section and the electromagnetic field enhancements of the tip plasmons. Our analysis demonstrates that the plasmon hybridization picture can be combined with numerical approaches to interpret the physical origin of the plasmons of highly complex nanostructures. 相似文献
93.
Eiji Saito Heesuk Kang Juan M. Taboas Alisha Diggs Colleen L. Flanagan Scott J. Hollister 《Journal of materials science. Materials in medicine》2010,21(8):2371-2383
The present study utilizes image-based computational methods and indirect solid freeform fabrication (SFF) technique to design
and fabricate porous scaffolds, and then computationally estimates their elastic modulus and yield stress with experimental
validation. 50:50 Poly (lactide-co-glycolide acid) (50:50 PLGA) porous scaffolds were designed using an image-based design technique, fabricated using indirect
SFF technique, and characterized using micro-computed tomography (μ-CT) and mechanical testing. μ-CT data was further used
to non-destructively predict the scaffold elastic moduli and yield stress using a voxel-based finite element (FE) method,
a technique that could find application in eventual scaffold quality control. μ-CT data analysis confirmed that the fabricated
scaffolds had controlled pore sizes, orthogonally interconnected pores and porosities which were identical to those of the
designed files. Mechanical tests revealed that the compressive modulus and yield stresses were in the range of human trabecular
bone. The results of FE analysis showed potential stress concentrations inside of the fabricated scaffold due to fabrication
defects. Furthermore, the predicted moduli and yield stresses of the FE analysis showed strong correlations with those of
the experiments. In the present study, we successfully fabricated scaffolds with designed architectures as well as predicted
their mechanical properties in a nondestructive manner. 相似文献
94.
Salthouse Timothy A.; Toth Jeffrey; Daniels Karen; Parks Colleen; Pak Richard; Wolbrette Michelle; Hocking Kellie J. 《Canadian Metallurgical Quarterly》2000,14(1):102
The Trail Making Test [TMT, R. M. Reitan, (see record 1960-00397-001), 1992] is extensively used in research in neuropsychology and in aging, in part because it has been postulated to reflect executive processes, such as planning and switching. However, neurocognitive and individual-difference based analyses of this test are complicated because of different spatial arrangements of targets, the use of letters only in Version B, and potential order effects when Version A is administered prior to Version B. The present article examines a variant of a TMT (called the Connections Test) that attempts to remedy these deficiencies. A structural equation model suggested that there were no direct effects of age on either the nonalternating or alternating versions of the Connections Test (analogous to TMT Versions A and B, respectively); rather, all age-related effects were mediated through effects on perceptual speed. Moreover, although the nonalternating and alternating versions were strongly related to one another, only the latter had significant independent relations with measures of higher order cognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
95.
Women's World Cup is one of the most significant events for girls and women in sports this century. The importance of mental skills for athletic success is certainly not new. Coaches and participants in every sport extol the importance of the four pillars of sport essential to competitive excellence—technical (requisite skills of a sport), tactical (strategies used), physiological (physical requirements), and psychological (mental skills). Most, however, focus almost exclusively on the first three dimensions. At its core, sport psychology addresses the psychological factors that influence performance in sport and the effects of that participation on the individual. Psychological skills mirror physical training parameters, As psychological skills are developed and refined with consistent, qualified, and systematic training, the benefits accruing from such training increase over the years. Although a majority of the members of the 1999 women's soccer team have been in psychological skills training for 4 or more years, several are early in their skills training development. Psychological skills training includes relaxation techniques, imagery, concentration and distraction control strategies, prepractice and precompetition preparation, positive self-talk and performance cues, goal setting, and team building. No counseling occurs from a clinical standpoint. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
96.
97.
Conversion of allylic hydroxy oleate to conjugated linoleic acid and methoxy oleate by acid-catalyzed methylation procedures 总被引:12,自引:0,他引:12
Martin P. Yurawecz Jennifer K. Hood John A. G. Roach Magdi M. Mossoba Daniel H. Daniels Yuoh Ku Michael W. Pariza Sou F. Chin 《Journal of the American Oil Chemists' Society》1994,71(10):1149-1155
Conjugated linoleic acid (CLA), a term describing a group of conjugated octadecadienoic acids that are both naturally occurring
and formed during food processing, is the subject of considerable current research because of the recently reported antioxidant
and anticarcinogenic properties of these compounds. Allylic hydroxy oleates (AHOs), secondary products of lipid autoxidation,
have also been found in foods. By means of high-performance liquid chromatography with ultraviolet detection, gas chromatography/mass
spectrometry and gas chromatography/matrix isolation/Fourier transform infrared spectroscopy, we determined that currently
used acid-catalyzed methylation procedures convert AHOs to CLA and other products that potentially yield high values in determination
of CLA in foods. A mixture of AHOs, containing mainly (8- and 11-)hydroxy-9-octadecadecenoates, was synthesized and tested
by methylation procedures with the following catalysts: BF3, HCl, NaOMe and tetramethylguanidine. Both the BF3 and the HCl procedures converted AHOs to CLA. The base-catalyzed procedures did not convert AHOs to CLA. 相似文献
98.
M. M. Mossoba M. P. Yurawecz J. A. G. Roach H. S. Lin R. E. McDonald B. D. Flickinger E. G. Perkins 《Lipids》1994,29(12):893-896
This study reports the structural elucidation of diunsaturated 5- or 6-membered ring cyclic fatty acid monomers (CFAM) isolated
from heated flaxseed oil by complementary gas chromatography (GC)-mass spectrometry (MS) and GC-matrix isolation-Fourier transform
infrared spectroscopy (MI-FTIR). Infrared measurements of CFAM were carried out on methyl ester derivatives as well-resolved
chromatograms were obtained on a polar 100% cyanopropyl polysiloxane capillary GC column. By contrast, electron ionization
MS of methyl ester derivatives was of limited value because of double bond migration during the ionization process in the
mass spectrometer. This communication reports definitive MS fragmentation patterns that can confirm ring position and double
bond position along the fatty acid chain in 1,2-disubstituted CFAM determined as 2-alkenyl-4,4-dimethyloxazoline derivatives.
Double bond configuration (cis, trans, or conjugatedcis,cis) in CFAM was confirmed by GC-MI-FTIR. The presence of CFAM, degradation products found in used frying oils, is a potential
source of dietary toxicity.
This work was presented in part at the 84th American Oil Chemists' Society Annual Meeting held in Anaheim, CA, in April 1993. 相似文献
99.
Recreational beaches constitute a large part of the 12 billion dollar per year tourism industry in Wisconsin. Beach closures due to microbial contamination are costly in terms of lost tourism revenue and adverse publicity for an area. Escherichia coli (E. coli), is used as an indicator of microbial contamination, as high concentrations of this organism should indicate a recent fecal contamination event that may contain other, more pathogenic, bacteria. An additional problem at many beaches in the state is the nuisance algae, Cladophora. It has been hypothesized that mats of Cladophora may harbor high concentrations of E. coli. Three beaches in Door County, WI were selected for study, based on tourist activity and amounts of algae present. Concentrations of E. coli were higher within Cladophora mats than in surrounding water. Beaches displayed an E. coli concentration gradient in water extending away from the Cladophora mats, although this was not statistically significant. Likewise, the amount of Cladophora observed on a beach did not correlate with E. coli concentrations found in routine beach monitoring samples. More work is needed to determine the impact of mats of Cladophora on beach water quality, as well as likely sources of E. coli found within the mats. 相似文献
100.
Inorganic ligand-modified, colloid-enhanced ultrafiltration (ILM-CEUF) is as a novel membrane-based separation method for selectively removing target ions from aqueous solution. Traditional colloid-enhanced ultrafiltration (CEUF) is a well-established membrane-based separation technique that can be used to separate metal ions from other aqueous solution components. Ligand-modified, colloid-enhanced ultrafiltration (LM-CEUF) uses organic ligands that selectively complex target ions and also associate with a water-soluble colloid, such as a surfactant micelle or polyelectrolyte. The colloid, associated -ligand, and target ion are then concentrated using an ultrafilter, producing a filtrate with a low concentration of the target ion. While traditional LM-CEUF techniques are able to provide quantitative separations of a variety of ionic pollutants, the high costs of the chelating agents make such techniques nonviable in most remediation schemes. This study investigated the replacement of organic ligands with carbonate for the selective removal of U(VI) from aqueous solution.In slightly to moderately basic solutions containing carbonate, UO2(CO3)34− can be made to dominate the U(VI) speciation. Using poly(diallyldimethylammonium) chloride, the effectiveness and efficiency of ILM-CEUF for removing U(VI) from other aqueous solution components was investigated as a function of carbonate concentration, pH, and ionic strength. Uranium separations of greater than 99.6% were achieved; even in the presence of large excesses of competing ions. The specific separation of U(VI) from Sr2+ was also examined. 相似文献