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排序方式: 共有365条查询结果,搜索用时 15 毫秒
51.
Jennifer Leah Black & Jacek Jaczynski 《International Journal of Food Science & Technology》2008,43(4):579-586
Water activity (aw) of ground beef, chicken breast meat, and trout fillets was modified to intermediate (aw 0.98–0.99) and lowest (aw 0.94–0.96) levels. The meat samples with modified and unaltered (native, aw 1.00) aw were inoculated with Escherichia coli O157:H7 and subjected to electron beam (e‐beam). Survivor curves were plotted and the D10‐values were calculated. The D10‐values ranged from 0.22 kGy for trout at native aw to 0.33 kGy for beef at intermediate, and chicken and trout at lowest aw. Regardless of the species, aw reduction increased E. coli resistance to e‐beam, suggesting that even small depletion of unbound water from food increases survival. The difference of the D10‐values between the samples at intermediate and lowest aw was insignificant. E‐beam could be used before aw‐reducing techniques are applied to food products. However, this would require stringent microbial control following e‐beam processing. The ‘tailing’ of survivors was observed for some samples with reduced aw. 相似文献
52.
Reconstitution of native and ruthenium-modified sperm whale myoglobins (Mb and Ru3Mb) with [OsII(MIX)(CO)(EtOH)] (MIX = mesoporphyrin IX-dicarboxylic acid) and [OsII(MIX)(DMF)2] yields carbonyl osmoglobin ([OsII(CO)][Mb]) and oxidized osmoglobins ([OsIII][Mb], [OsIII][Ru3Mb]). The visible spectrum of [OsII(CO)][Mb] exhibits and bands at 538 and 510 nm, respectively. The ascorbate reduction of dioxygen to water is catalyzed by [OsIII][Ru3Mb].Contribution No. 7720 from the Arthur Amos Noyes Laboratory, California Institute of Technology, Pasadena, California 911255, U.S.A., and the Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong. 相似文献
53.
Nanocarriers as an emerging platform for cancer therapy 总被引:6,自引:0,他引:6
Nanotechnology has the potential to revolutionize cancer diagnosis and therapy. Advances in protein engineering and materials science have contributed to novel nanoscale targeting approaches that may bring new hope to cancer patients. Several therapeutic nanocarriers have been approved for clinical use. However, to date, there are only a few clinically approved nanocarriers that incorporate molecules to selectively bind and target cancer cells. This review examines some of the approved formulations and discusses the challenges in translating basic research to the clinic. We detail the arsenal of nanocarriers and molecules available for selective tumour targeting, and emphasize the challenges in cancer treatment. 相似文献
54.
Zhang Y.M. Piprek J. Margalit N. Anzlowar M. Bowers J. 《Lightwave Technology, Journal of》1999,17(3):503-508
The low-temperature performance of vertical cavity lasers (VCL's) is of interest for high-speed data transmission from superconducting and cryogenic semiconductor circuits. Our double-fused 1.5 μm lasers employ a strain-compensated InGaAsP-InP multiquantum-well (MQW) active region that is sandwiched between two AlGaAs-GaAs distributed Bragg reflectors. Continuous wave (CW) lasing at ambient temperature as low as 7 K is measured on the same type of top-emitting devices that previously lased at a record-high temperature of 337 K. The optimum temperature is found at 180 K giving minimum threshold current, maximum modulation bandwidth of 5 GHz, and more than 3 GHz/mA1/2 modulation current efficiency. The optimum temperature agrees very well with the theoretical prediction. Further device optimization for cryogenic high-speed applications is discussed in detail 相似文献
55.
Ortal Danino Hugo E. Gottlieb Shlomo Grossman Margalit Bergman 《Food research international (Ottawa, Ont.)》2009,42(9):1273-1280
Inula viscosa is a perennial herbaceous plant used topically in folk medicine as an anti-scabies, anti-inflammatory, and wound-healing agent. We examined the antioxidant activity of the methanolic extract of I. viscosa. We isolated and identified several polyphenolic antioxidants from I. viscosa leaves and focused on 1,3-dicaffeoylquinic acid (1,3-diCQA). Antioxidant activity was measured using ABTS and DPPH assays, which measure antioxidant activity. The concentrations of 1,3-diCQA required for the inhibition of oxidation were lower than those required by other known antioxidants. 1,3-diCQA inhibited oxidative damage caused by various factors, including FeSO4 and AAPH (2,2′-azobis(2-amidinopropane) dehydrochloride). Antioxidant activity can also be detected by the ability of a compound to scavenge reactive oxygen species (ROS). 1,3-diCQA was found to scavenge hydroxyl radical and superoxide radicals, as measured by electron spin resonance (ESR). These data demonstrate that 1,3-diCQA exhibits antioxidant properties, probably through the involvement of a direct scavenging effect on several free radicals. 相似文献
56.
Deying Xia Leah M. Johnson Gabriel P. López 《Advanced materials (Deerfield Beach, Fla.)》2012,24(10):1287-1302
This review article provides a brief summary of recent research progress on anisotropic wetting on one‐dimensional (1D) and directionally patterned surfaces, as well as the technical importance in various applications. Inspiration from natural structures exhibiting anisotropic wetting behavior is first discussed. Development of fabrication techniques for topographically and chemically 1D patterned surfaces and directional nanomaterials are then reviewed, with emphasis on anisotropic behavior with topographically (structurally) patterned surfaces. The basic investigation of anisotropic wetting behavior and theoretical simulations for anisotropic wetting are also further reviewed. Perspectives concerning future direction of anisotropic wetting research and its potential applications in microfluidic devices, lab‐on‐a‐chip, sensor, microreactor and self‐cleaning are presented. 相似文献
57.
Synthesis of monodisperse, covalently cross-linked, degradable "smart" microgels using microfluidics
Kesselman LR Shinwary S Selvaganapathy PR Hoare T 《Small (Weinheim an der Bergstrasse, Germany)》2012,8(7):1092-1098
The development of a robust method for the synthesis of highly monodisperse microgels cross-linked with degradable covalent bonds offers the potential for fabricating microgels with the highly controllable porosities, cell interactions, and degradation half-lives required for biomedical applications. A microfluidic chip is designed that enables the on-chip mixing and emulsification of two reactive polymer solutions (hydrazide and aldehyde-functionalized carbohydrates) to form monodisperse, hydrazone cross-linked microgels in the size range of ≈40-100 μm. The device can be run continuously for at least 30 h without a significant drift in particle size. The resulting microgels have a homogeneous bulk composition and can swell and deswell as the solvent conditions change in predictable ways based on the chemistry of the reactive polymers used, thereby enabling improved control over both the chemistry and morphology of the resulting microgels relative to other reported approaches. The in situ gelation chemistry used facilitates rapid microgel formation within the droplets without requiring the use of UV light or heating to initiate polymerization, thus making this approach of particular potential utility in cell encapsulation or drug delivery (as demonstrated). 相似文献
58.
Nick Haslam Lauren Ban Leah Kaufmann Stephen Loughnan Kim Peters Jennifer Whelan Sam Wilson 《Scientometrics》2008,76(1):169-185
Factors contributing to citation impact in social-personality psychology were examined in a bibliometric study of articles
published in the field’s three major journals. Impact was operationalized as citations accrued over 10 years by 308 articles
published in 1996, and predictors were assessed using multiple databases and trained coders. Predictors included author characteristics
(i.e., number, gender, nationality, eminence), institutional factors (i.e., university prestige, journal prestige, grant support),
features of article organization (i.e., title characteristics, number of studies, figures and tables, number and recency of
references), and research approach (i.e., topic area, methodology). Multivariate analyses demonstrated several strong predictors
of impact, including first author eminence, having a more senior later author, journal prestige, article length, and number
and recency of references. Many other variables — e.g., author gender and nationality, collaboration, university prestige,
grant support, title catchiness, number of studies, experimental vs. correlational methodology, topic area — did not predict impact. 相似文献
59.
Spinks D Torrie LS Thompson S Harrison JR Frearson JA Read KD Fairlamb AH Wyatt PG Gilbert IH 《ChemMedChem》2012,7(1):95-106
Trypanothione synthetase (TryS) is essential for the survival of the protozoan parasite Trypanosoma brucei, which causes human African trypanosomiasis. It is one of only a handful of chemically validated targets for T. brucei in vivo. To identify novel inhibitors of TbTryS we screened our in-house diverse compound library that contains 62,000 compounds. This resulted in the identification of six novel hit series of TbTryS inhibitors. Herein we describe the SAR exploration of these hit series, which gave rise to one common series with potency against the enzyme target. Cellular studies on these inhibitors confirmed on-target activity, and the compounds have proven to be very useful tools for further study of the trypanothione pathway in kinetoplastids. 相似文献
60.
The behaviour of water in nanopores is very different from that of bulk water. Close to hydrophobic surfaces, the water density has been found to be lower than in the bulk, and if confined in a sufficiently narrow hydrophobic nanopore, water can spontaneously evaporate. Molecular dynamics simulations have suggested that a nanopore can be switched between dry and wet states by applying an electric potential across the nanopore membrane. Nanopores with hydrophobic walls could therefore create a gate system for water, and also for ionic and neutral species. Here, we show that single hydrophobic nanopores can undergo reversible wetting and dewetting due to condensation and evaporation of water inside the pores. The reversible process is observed as fluctuations between conducting and non-conducting ionic states and can be regulated by a transmembrane electric potential. 相似文献