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61.
Tirri T Rich J Wolke J Seppälä J Yli-Urpo A Närhi TO 《Journal of materials science. Materials in medicine》2008,19(8):2919-2923
The aim of this study was to investigate in vitro bioactivity of different thermoplastic biodegradable barrier membranes. Three experimental GBR membranes were fabricated using Poly(epsilon-caprolactone-co-D: ,L-lactide) P(CL/DL-LA) and particulate bioactive glass S53P4 (BAG; granule size 90-315 microm): (A) composite membrane with 60-wt.% of BAG, (B) membrane coated with BAG; and (C) copolymer membrane without BAG. Membranes were immersed in simulated body fluid (SBF), and their surfaces were characterized with SEM, XRD and EDS after 6 and 12 h and after 1, 3, 5, 7, and 14 days. Calcium phosphate (Ca-P) surface formation was observed on both composite membranes (A and B) but not on the copolymer membrane without bioactive glass (C). The Ca-P precipitation appeared to be initiated on the bioactive glass followed by growth of the layer along the polymer surface. In 6-12 h ion dissolution of the bioactive glass led to formation of the silica rich layer on the surface of the exposed glass granules on composite membrane B whereas only small amounts of silica was observed on the polymer surface of the composite membrane A. At 24 h nucleation of Ca-P precipitation was observed, and by 3-5 days membrane surface was covered with a uniform Ca-P layer transforming from amorphous to low crystalline structure. At 7 days composition and structure of the apatite surface resembled the apatite in bone. Once nucleated, the surface topography seemed to have significant effect on the growth of the apatite layer. 相似文献
62.
Robert A. Bauer Robert Smulders Johanna G. M. Becht Paul J. van der Put Joop Schoonman 《Journal of the American Ceramic Society》1989,72(7):1301-1304
The laser-chemical vapor precipitation (L-CVP) of Si3 N4 powders from miktures of SiH2 Cl2 and NH3 or SiC1,4 and NH3 , was studied. The reactant gases were mixed in the laser beam, thus preventing low-temperature reactions. In a high-temperature electrostatic precipitator (ESP), Si3 N, was collected and separated from the waste product NH4 Cl. In the ESP, Si was collected at a lower temperature. A major problem in utilizing chlorinated silanes was their poor absorption of the 10.6-μm radiation. SF6 was explored for use as an inert sensitizer. Si was prepared from SiH2 Cl2 . Particle diameters were typically 20 to 40 nm for Si3N4 and 50 nm for Si. 相似文献
63.
Mauro Schettino Donato A. Grasso Berhane T. Weldegergis Cristina Castracani Alessandra Mori Marcel Dicke Joop C. Van Lenteren Joop J. A. Van Loon 《Journal of chemical ecology》2017,43(10):1007-1022
In response to herbivory by insects, various plants produce volatiles that attract enemies of the herbivores. Although ants are important components of natural and agro-ecosystems, the importance of herbivore-induced plant volatiles (HIPVs) as cues for ants for finding food sources have received little attention. We investigated responses of the ant Formica pratensis to volatiles emitted by uninfested and insect-infested cucumber (Cucumis sativus) and potato (Solanum tuberosum) plants. Cucumber plants were infested by the phloem-feeding aphid Aphis gossypii, the leaf chewer Mamestra brassicae or simultaneously by both insects. Potato plants were infested by either Aphis gossypii, by the leaf chewer Chrysodeixis chalcites or both. In olfactometer experiments, ants preferred volatile blends emitted by cucumber plants infested with M. brassicae caterpillars alone or combined with A. gossypii to volatiles of undamaged plants or plants damaged by A. gossypii only. No preference was recorded in choice tests between volatiles released by aphid-infested plants over undamaged plants. Volatiles emitted by potato plants infested by either C. chalcites or A. gossypii were preferred by ants over volatiles released by undamaged plants. Ants did not discriminate between potato plants infested with aphids and caterpillars over plants infested with aphids only. Plant headspace composition showed qualitative and/or quantitative differences between herbivore treatments. Multivariate analysis revealed clear separation between uninfested and infested plants and among herbivore treatments. The importance of HIPVs in indirect plant defence by ants is discussed in the context of the ecology of ant-plant interactions and possible roles of ants in pest management. 相似文献
64.
A Novel Synthetic Odorant Blend for Trapping of Malaria and Other African Mosquito Species 总被引:1,自引:1,他引:0
Mukabana WR Mweresa CK Otieno B Omusula P Smallegange RC van Loon JJ Takken W 《Journal of chemical ecology》2012,38(3):235-244
Estimating the biting fraction of mosquitoes is of critical importance for risk assessment of malaria transmission. Here,
we present a novel odor-based tool that has been rigorously assessed in semi-field assays and traditional African villages
for estimating the number of mosquitoes that enter houses in search of a blood meal. A standard synthetic blend (SB) consisting
of ammonia, (S)-lactic acid, tetradecanoic acid, and carbon dioxide was complemented with isovaleric acid, 4,5 dimethylthiazole,
2-methyl-1-butanol, and 3-methyl-1-butanol in various combinations and concentrations, and tested for attractiveness to the
malaria mosquito Anopheles gambiae. Compounds were released through low density polyethylene (LDPE) material or from nylon strips (nylon). Studies were done
in a semi-field facility and two traditional villages in western Kenya. The alcohol 3-methyl-1-butanol significantly increased
the attraction of SB. The other compounds proved less effective or inhibitory. Tested in a village, 3-methyl-1-butanol, released
from LDPE, increased the attraction of SB. Further studies showed a significantly enhanced attraction of adding 3-methyl-1-butanol
to SB compared to previously-published attractive blends both under semi-field and village conditions. Other mosquito species
with relevance for public health were collected with this blend in significantly higher numbers as well. These results demonstrate
the advent of a novel, reliable odor-based sampling tool for the collection of malaria and other mosquitoes. The advantage
of this odor-based tool over existing mosquito sampling tools is its reproducibility, objectiveness, and relatively low cost
compared to current standards of CDC light traps or the human landing catch. 相似文献
65.
Lipase‐catalyzed reactions and supercritical technology are powerful tools that can be effectively combined for the modification and processing of fats. In addition, both are “green” technologies, which can produce high‐quality, food‐grade products without the need of additional solvents. We show two examples in which milk fat was used as raw material for the production of added‐value derivatives: short‐chain fatty acid ethyl esters, which are natural flavor agents; and a diacylglycerol‐based, potentially superior dietary fat. In both cases we applied a combination of lipases and supercritical carbon dioxide extraction for the synthesis and separation of products. 相似文献
66.
ABSTRACT: The aim of this study is to prepare and characterize two types of silver-functionalized carbon nanofiber (CNF) composite electrodes, i.e., silver-decorated CNF-epoxy and silver-modified natural zeolite-CNF-epoxy composite electrodes suitable for ibuprofen detection in aqueous solution. Ag carbon nanotube composite electrode exhibited the best electroanalytical parameters through applying preconcentration/differential-pulsed voltammetry scheme. 相似文献
67.
采用透明石英玻壳的金属卤化物灯用作汽车前灯非常有吸引力 ,这是因为其高光效和长寿命。然而某些光源 ,特别是欧洲的汽车近光灯 ,必须采取遮光措施 :一方面为了避免由光源中心部位光散射刺激造成的弦光 ;另一方面为了减小在配光曲线中产生截止的反射器部分的光发射表面 ,其结果是光损失非常大。降低内管直径是不可能的 ,因为石英经受不了相应来讲更高的管壁温度。即使再采用加厚管壁的方法 ,也降低不了多少管壁温度 ,况且管壁的加厚还对灯的启动有负作用。为此我们研究了薄管壁耐高温陶瓷玻壳的可行性。1 灯的特性参数1 1 灯尺寸、管壁… 相似文献
68.
Maaike Bruinsma Dani Lucas-Barbosa Cindy J. M. ten Broeke Nicole M. van Dam Teris A. van Beek Marcel Dicke Joop J.A. van Loon 《Journal of chemical ecology》2014,40(1):39-49
Herbivory induces changes in plants that influence the associated insect community. The present study addresses the potential trade-off between plant phytochemical responses to insect herbivory and interactions with pollinators. We used a multidisciplinary approach and have combined field and greenhouse experiments to investigate effects of herbivory in plant volatile emission, nectar production, and pollinator behavior, when Pieris brassicae caterpillars were allowed to feed only on the leaves of Brassica nigra plants. Interestingly, volatile emission by flowers changed upon feeding by herbivores on the leaves, whereas, remarkably, volatile emission by leaves did not significantly differ between infested and non-infested flowering plants. The frequency of flower visits by pollinators was generally not influenced by herbivory, but the duration of visits by honeybees and butterflies was negatively affected by herbivore damage to leaves. Shorter duration of pollinator visits could be beneficial for a plant, because it sustains pollen transfer between flowers while reducing nectar consumption per visit. Thus, no trade-off between herbivore-induced plant responses and pollination was evident. The effects of herbivore-induced plant responses on pollinator behavior underpin the importance of including ecological factors, such as herbivore infestation, in studies of the ecology of plant pollination. 相似文献
69.
Carolien L. Huisman Joop Schoonman Albert Goossens 《Solar Energy Materials & Solar Cells》2005,85(1):115-124
The synthesis and characterization of nanostructured heterojunction solar cells based on inverse opal titanium dioxide (TiO2) films is discussed. Photonic films with thicknesses of 0.9 and 3.7 μm are deposited using self-organisation of latex spheres with diameters of 400 and 100 nm. The voids between the spheres are filled with a TiO2 precursor and a subsequent heat treatment yields a highly organized porous structure. Sensitization with Ru 535-dye (cis-[L2Ru(SCN)2] in which L is 2,2′-dipyridine-4,4′-dicarboxylic acid), yields solar cells with a power conversion efficiency of 0.6% under simulated solar light. At present, the small area of the ordered structure is limiting the performance of the cells. These cells may be promising for future applications, if improved fabrication techniques will enable an enlargement of the ordered area. 相似文献
70.
Lise T. de Jonge Sander C. G. Leeuwenburgh Jeroen J. J. P. van den Beucken Joop G. C. Wolke John A. Jansen 《Advanced functional materials》2009,19(5):755-762
The biological performance of orthopedic and oral implants can be significantly improved by functionalizing the non‐physiological metallic implant surface through the application of biologically active coatings. In this paper, a cost‐effective alternative to traditional biomedical coatings for bone substitution through exploitation of the specific advantages of the electrospray deposition technique for the immobilization of the enzyme alkaline phosphatase (ALP) onto the implant surface is presented. Since ALP increases the local inorganic phosphate concentration required for physiological mineralization of hard tissues, ALP coatings will enable enzyme‐mediated mineralization onto titanium surfaces. To evaluate the bone‐bioactive capacity of the ALP‐coated titanium surface, soaking experiments are performed. Although the purely inorganic so‐called simulated body fluid is the standard in vitro procedure for predictive studies on potential bone bonding in vivo, an alternative testing solution is proposed that also contains organic phosphates (cell culture medium supplemented with the organic β‐b;‐glycerophosphate (β‐b;‐GP) and serum proteins), thereby resembling the in vivo conditions more closely. Under these physiological conditions, the electrosprayed ALP coatings accelerated mineralization onto the titanium surface as compared to noncoated implant material by means of enzymatic pathways. Therefore, this novel approach toward implant fixation holds significant promise. 相似文献