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81.
Vladimir Kocourek Ludmila Havlíková Irena Zemanová 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1987,185(1):14-16
Summary The kinetics of the photodegradation of synthetic pyrethroids (permethrin, cypermethrin and deltamethrin) on the surface of treated grain were investigated. Pyrethroids are quickly degraded if spread in a thin layer on a glass plate and photodecomposition proceeds more slowly on UV-irradiated grain. Moreover, in the latter case the degradation of pyrethroids was incomplete. The residual levels of all compounds after 15 min UV-irradiation depended on the storage time which elapsed between treatment of the grain and irradiation. The results indicate that the synthetic pyrethroids are able to penetrate inside the grain and that the UV-irradiation technique could be a tool to study this penetration.
Die Photostabilität der synthetischen Pyrethroide auf Getreide
Zusammenfassung Die Kinetik der Zersetzung durch Licht synthetischer Pyrethroide (Permethrin, Cypermethrin und Deltamethrin) auf der Oberfläche von Getreidekörnern wurde untersucht. Pyrethroide, die in einer dünnen Schicht auf eine Glasplatte gesprüht sind, zerfallen schnell, ihre Zersetzung auf der Oberfläche des Getreidekornes erfolgt nach UV-Behandlung langsamer. Die Zersetzung der Pyrethroide war unter diesen Bedingungen unvollständig und der Gehalt an Rückstand hängt bei allen Pyrethroiden (nach 15 min UV-Belichtung) von der Zeit zwischen Körnerbehandlung und Belichtung ab. Diese Ergebnisse weisen darauf hin, daß die synthetischen Pyrethroide ins Korninnere dringen können und daß die Technik der UV-Behandlung für die Untersuchung dieser Effekte verwendet werden kann.相似文献
82.
Irena B. Agater Kenneth J. Briant Jeffery W. Llewellyn Ronald Sawyer Francis J. Bailey Christopher H. S. Hitchcock 《Journal of the science of food and agriculture》1986,37(3):317-331
The detection and measurement of characteristic peptides formed on enzymatic hydrolysis of soya protein products, meats and offals is described. Samples were heated at 120°C for 3h prior to digestion with trypsin overnight, and the resultant peptide mixtures passed through an Amicon ultrafiltration membrane. After concentration the ultrafiltrates were analysed by ion exchange chromatography on Aminex A5 resin. Peptides were detected by post-column reaction with ninhydrin. Characteristic peaks designated SP 2 and MP 1 were seen in chromatograms of digests of soya protein isolate and beef respectively, and these peaks were well resolved in beef and soya protein isolate mixtures. The SP 2 peak was shown to contain peptides derived from soya 11 S globulin. The soya protein and beef contents of a series of mixtures of freeze-dried, defatted beef and soya protein isolate were determined by measurement of the SP 2 and MP 1 peaks respectively. Soya protein content could be determined within 2% of the true value over the range 30–70% soya protein isolate and beef content could be determined within 5% of the true value in the range 20–100% beef. Analysis of five soya protein isolates, four soya protein concentrates, six soya flours and 13 textured soya products indicated considerable interproduct variation in the yield of SP 2. The MP 1 peak was seen in a range of meats, both cooked and raw. It was also present in digests of offals which contained smooth or striated muscle but not in ‘non-muscle’ offals. The protein origin of the MP 1 peak was not established but the yield appeared lower in meat products which had been heated during manufacture than in those which had received no such treatment. Analysis of a series of laboratory prepared canned and heated pork and soya protein isolate mixtures enabled the pork content to be determined to within 8% of the true value, 2% soya protein isolate could be detected but not quantified accurately. 相似文献
83.
Hájek M Dezortová M Wagnerová D Skoch A Voska L Hejlová I Trunečka P 《Magma (New York, N.Y.)》2011,24(5):297-304
Object
Among several non-invasive methods of liver fat analysis, the most important role is played by MR imaging and spectroscopy (MRS). This study describes the 1H MRS at 3T measurement of liver fat volume fraction ffat{\phi_{{\rm fat}}} in a group of liver transplant patients, an at-risk group for the development of de novo steatosis. 相似文献84.
Jan Suchanicz Irena Jankowska-Sumara Tatiana V. Kruzina 《Journal of Electroceramics》2011,27(2):45-50
Lead-free Na0.5Bi0.5TiO3 -BaTiO3 ceramics have been prepared in the whole range of concentrations and studied at room-temperature by means of X-ray, Raman
scattering and infrared techniques. X-ray measurements revealed rhombohedral, rhombohedral-tetragonal boundaries and tetragonal
modifacations depending on the contents of BaTiO3. The distinct changes of the Raman and infrared spectra with increasing of BaTiO3 content, which were correlated with X-ray results, were observed. The broad phonon spectra indicated the disorder in the
A site of Na0.5Bi0.5TiO3 -BaTiO3 system. 相似文献
85.
Sagnella SM Gong X Moghaddam MJ Conn CE Kimpton K Waddington LJ Krodkiewska I Drummond CJ 《Nanoscale》2011,3(3):919-924
We demonstrate that oral delivery of self-assembled nanostructured nanoparticles consisting of 5-fluorouracil (5-FU) lipid prodrugs results in a highly effective, target-activated, chemotherapeutic agent, and offers significantly enhanced efficacy over a commercially available alternative that does not self-assemble. The lipid prodrug nanoparticles have been found to significantly slow the growth of a highly aggressive mouse 4T1 breast tumour, and essentially halt the growth of a human MDA-MB-231 breast tumour in mouse xenografts. Systemic toxicity is avoided as prodrug activation requires a three-step, enzymatic conversion to 5-FU, with the third step occurring preferentially at the tumour site. Additionally, differences in the lipid prodrug chemical structure and internal nanostructure of the nanoparticle dictate the enzymatic conversion rate and can be used to control sustained release profiles. Thus, we have developed novel oral nanomedicines that combine sustained release properties with target-selective activation. 相似文献
86.
Elena Pâslaru Lidija Fras Zemljic Matej Bračič Alenka Vesel Irena Petrinić Cornelia Vasile 《应用聚合物科学杂志》2013,130(4):2444-2457
A two‐step procedure was applied to obtain antimicrobial films; this procedure involved a corona treatment of the polyethylene (PE) surface and its chemical activation with 1‐ethyl‐3‐[3‐dimethylaminopropyl] carbodiimide hydrochloride and N‐hydroxysuccinimide, and this led to the covalent bonding of chitosan on the PE surface. Electrochemical methods were used to investigate the stability of the deposited chitosan layer. The potentiometric and polyelectrolyte titrations showed that some amount of chitosan desorbed faster from the surface until equilibrium was reached and also that the grafted chitosan layer was more stable than the physically adsorbed one. The chitosan immobilized on the PE surface exhibited the expected antibacterial activity when tested against three bacteria, which included two Gram‐negative bacteria, Salmonella enteritidis and Escherichia coli, and one Gram‐positive bacterium, Listeria monocytogenes. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2444–2457, 2013 相似文献
87.
The long lead time required to add new capacity in the electricity generation industry means that daily demands are necessarily served by capacity already installed. However, in a competitive market, even if the installed capacity was designed to serve the projected demands, frequent surpluses and occasional full utilization inevitably lead to price volatility. This paper develops a two-stage model of the generation market in which capacity construction occurs in stage 1, before demand realization, and price determination occurs in stage 2, when the equilibrium price ensures that the realized demand does not exceed the installed capacity. We show that price volatility and price spikes are inevitable, and that while price capping can mitigate high and volatile prices, it causes unmet demands and reduction in system reliability. This paper accentuates the interdependence among generating capacity, price volatility and service reliability, a primary cause of concern in the debate on electricity market reform. 相似文献
88.
This paper investigates the plastic deformation in mono-crystalline silicon under complex loading conditions. With the aid of various characterization techniques, it was found that the mechanism of plasticity in silicon is complex and depends on loading conditions, involving dislocations, phase transformations and chemical reactions. In general, plastic deformation in silicon is the coupled result of mechanical deformation controlled by the stress field applied, chemical reaction determined by the external loading environment, and mechanical–chemical interaction governed by both the loading type and environment. Temperature rise accelerates the penetration of oxygen into silicon and reduces the critical stress of plastic yielding. When the chemical effect is avoided, the initiation of plasticity is enabled by octahedral shear stress but the further development of plastic deformation is influenced by hydrostatic stress. Plasticity of silicon in the form of phase transformations, e.g., from the diamond to amorphous or from the amorphous to bcc structures, is determined by loading history. 相似文献
89.
Irene J. A. Baker Barry Matthews Hector Suares Irena Krodkiewska D. Neil Furlong Franz Grieser Calum I. Drummond 《Journal of surfactants and detergents》2000,3(1):1-11
Ultimate aerobic biodegradabilities of an array of sugar ester surfactants were determined by International Standards Organisation
method 7827, “Water Quality—Evaluation in an Aqueous Medium of the Aerobic Biodegradability of Organic Compounds, Method by
Dissolved Organic Carbon” (1984). The surfactants were nonionic sugar esters with different-sized sugar head groups (formed
from glucose, sucrose, or raffinose) and different lengths and numbers of alkyl chains [formed from lauric (C12) or palmitic (C16) acid]. Analogous anionic sugar ester surfactants, formed by attaching an α-sulfonyl group adjacent to the ester bond, and
sugar esters with α-alkyl substituents were also studied. It was found that variations in sugar head group size or in alkyl
chain length and number do not significantly affect biodegradability. In contrast, the biodegradation rate of sugar esters
with α-sulfonyl or α-alkyl groups, although sufficient for them to be classified as readily biodegradable, was dramatically
reduced compared to that of the unsubstituted sugar esters. An understanding of the relationship between structure and biodegradability
provided by the results of this study will aid the targeted design of readily biodegradable sugar ester surfactants for use
in consumer products. 相似文献
90.