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排序方式: 共有846条查询结果,搜索用时 0 毫秒
91.
92.
This paper describes the architecture and the performance of a new programmable 16-bit Digital Signal Processor (DSP) engine. It is developed specifically for next generation wireless digital systems and speech applications. Besides providing a basic instruction set, similar to current day 16-bit DSP's, it contains distinctive architectural features and unique instructions, which make the engine highly efficient for compute-intensive tasks such as vector quantization and Viterbi operations. The datapath contains two Multiply-Accumulate units and one ALU. The external memory bandwidth is kept to two data busses and two corresponding address busses. Still, the internal bus network is designed such that all three units are operating in parallel. This parallelism is reflected in the performance benchmarks. For example, an FIR filter of N taps will take N/2 instruction cycles compared to N for a general purpose 16-bit DSP, and it will require only half the number of memory accesses of a general purpose DSP. This efficiency is reflected in the very low MIPS requirement to implement cellular standards. 相似文献
93.
94.
Ingrid Aguiló-Aguayo Robert Soliva-Fortuny & Olga Martín-Belloso 《International Journal of Food Science & Technology》2009,44(11):2268-2277
The effects pulse frequency (50–250 Hz), pulse width (1.0–7.0 μs) and polarity (monopolar or bipolar) of high-intensity pulsed electric field treatments (35 kV cm−1 and 1000 μs) on viscosity and the pectin methylesterase (PME) and polygalacturonase (PG) activities were evaluated using a response surface methodology. Second-order expressions were accurate enough to fit experimental results. Tomato juice apparent viscosity increased within the range of the assayed conditions, achieving the highest values at 250 Hz and 7.0 μs in bipolar mode. At the same conditions the lowest residual PME (RAPME = 10%) and PG (RAPG = 45%) activities were observed in the juice. Apparent viscosity of strawberry juices slightly rose when frequencies higher than 100 Hz and 1-μs monopolar pulses were applied to the juice. Treatments causing the greatest increase in strawberry juice apparent viscosity also led to the lowest RAPME (10%) and RAPG (75%) values. In contrast, viscosity loss was promoted under the rest of assayed HIPEF conditions despite the low RAPME values (<20%) achieved. Moreover, RAPG did not decrease below 75% throughout the range of studied conditions. 相似文献
95.
Börje Lindqvist Jörgen Östgren Ingrid Lindberg 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1975,159(1):15-22
Summary A procedure is described in which stepwise regression is adapted to permit comparison of the amino-acid pattern from a composite sample with those of simple substances arranged in an easily accessible data bank. The computer program automatically selects from the bank those proteins whose amino-acid patterns best correspond to that of the sample, and calculates the proportion of the proteins contained in the mixture.The procedure is applicable to food analytical problems that involve the identification and determination of proteins in mixtures, and also to situations in which the properties of the proteins have been altered by denaturation or enzymatic degradation. The determination is limited to 3–4 proteins in the mixture.
Identifizierung und quantitative Bestimmung einzelner Proteine in Mischungen von denaturierten Proteinen mit Hilfe ihrer Aminosäauremuster
Zusammenfassung Mit Hilfe einer stufenweisen Regressionsberechnung konnen Aminosäu-renmuster eines zusammengesetzten Proteins mit einfachen Proteinen verglichen werden. Mit dieser Berechnung werden aus einer Sammlung von Vergleichsproteinen automatisch solche Proteine ausgewählt, deren Aminosäurenmuster am besten zu der der Probe paßt. Gleichzeitig können dadurch die Verhältnisse der verschiedenen Proteine in der Mischung berechnet werden. Durch these Arbeitsweise konnen weiterhin bei nahrungsanalytischen Problemen Proteine in Mischungen identifiziert and quantitativ erfaßt werden, selbst worn die Proteine denaturiert oder enzymatisch abgebaut sind, jedoch ist das Verfahren auf 3–4 Proteine in der Mischung begrenzt.相似文献
96.
Ingrid Brueckner 《Computer aided design》1980,12(1):21-24
A simple algorithm is given which calculates the Bézier points of a surface over a quadrangle from the given generalized Bézier points of the surface over a triangle. An example is added. 相似文献
97.
Johnsrude Ingrid S.; Weary Daniel M.; Ratcliffe Laurene M.; Weisman Ronald G. 《Canadian Metallurgical Quarterly》1994,108(2):172
Two experiments to examine the effects of motivational context on the perception of conspecific song by cowbirds were conducted. In the 1st experiment, sexual displays were elicited from females by playback of normal song and rearranged sequences of the component phrases. In a 2nd experiment, male and female cowbirds discriminated among the same songs in a food-rewarded operant procedure. In a sexual context, the birds were sensitive to both the beginning and end phrases of normal song, whereas in a food context, the birds were more sensitive to the beginning of normal song. In both experiments, 1-phrase songs were better discriminated from normal song than 2-phrase songs, and there was no effect of phrase order on discrimination. Similarities and differences in the results of the 2 experiments suggest that some aspects of cowbird song perception remain constant across motivational contexts, whereas others are unique to particular motivational contexts. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
98.
99.
Ingrid Fogy Erich R. Schmid und Josef F. K. Huber 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1980,170(3):194-199
Zusammenfassung Carbamatpesticide können auch in sehr komplex zusammengesetzten Obst- und Gemüsearten mit Hilfe der mehrdimensionalen Hochdruckflüssigkeitschromatographie im ppm-Bereich nachgewiesen werden. Dabei wird eine Fraktion des Effluents der ersten Säule, die das von Matrixbestandteilen nur unvollständig getrennte Pesticid enthält, mittels eines Schalthahns auf eine zweite Säule mit einer anderen stationären Phase gebracht, wo die Trennung vervollständigt wird. Die erhöhte Auflösung im Zweisäulen Betrieb wird durch die unterschiedlichen Selektivitätskoeffizienten von Wirkstoff und störenden Pflanzenbestandteilen in den beiden Phasensystemen bewirkt. Daneben kann man bei geeigneter Wahl der Fraktionsgrenzen eine relative Anreicherung des Carbamateserreichen. Da bei den verwendeten Phasensystemen die meisten Pflanzenbestandteile relativ schnell eluiert werden, gelingt besonders bei Carbamaten mit hohem Kapazitätskoeffizienten eine eindeutige Identifizierung und Quantifizierung manchmal schon mit der ersten chromatographischen Säule allein. Wegen der hohen Trennkapazität der mehrdimensionalen Hochdruckflüssigkeitschromatographie besteht die Probenvorbereitung nur aus einer Extraktion des Pflanzenmaterials mit Dichlormethan. Nach Ersatz des Extraktionsmittels durch die mobile Phase kann die Lösung direkt in den Flüssigkeitschromatographen injiziert werden.
Determination of carbamate pesticides in fruits and vegetables by multi-dimensional high pressure liquid chromatography
Summary Carbamate pesticides can be determined at the ppm level even in very complex extracts of different kinds of fruits and vegetables by means of multidimensional high pressure liquid chromatography. The effluent fraction of the first column containing the pesticide insufficiently separated from matrix compounds is transferred by column-switching to a second column with another stationary phase, where the separation is completed. The improved resolution in the two-column mode is caused by the different selectivity coefficients of carbamate and plant components for the two phase systems used. Furthermore, a relative enrichment of the carbamate can be achieved by a suitable choice of size and position of the transferred fraction. Carbamates with a high capacity factor can be determined on a single chromatographic column in general, since most plant constituents are eluted early on this type of column.Due to the high separating power of multidimensional high pressure liquid chromatography the sample pretreatment consists only of an extraction of the plant material with dichloromethane. After replacing the extraction solvent by the mobile phase the sample can be injected directly into the liquid chromatograph.相似文献
100.
Bonded neodymium-iron-boron (NdFeB) permanent magnets in a paired configuration were successfully used to control mass transport in redox-based, magnetohydrodynamics (MHD). Control of fluid flow based on magnetic fields has potential for use in portable lab-on-a-chip (LOAC) and analytical devices. Bonded magnets, composed of magnetic powder and organic binder materials, are less expensive and easier to fabricate and pattern than electromagnets and sintered permanent magnets, which have been previously used in MHD studies on electrochemical systems. The ability to pattern bonded magnets near and around the electrodes is expected to allow for better control over the magnetic field distribution and solution flow. Current was generated at an 800-microm-radius platinum disk electrode in a solution of 0.06 M nitrobenzene and 0.5 M tetra-n-butylammonium hexafluorophosphate in acetonitrile. Increases in limiting current in the presence of the magnetic field, which indicate enhancement in mass transport, for sintered (210+/-14%, N = 4, where B(r) = 1.23 T and magnetic field strength is 0.55 T) and bonded (94+/-8%, N = 4, where B(r) = 0.41 T and magnetic field strength is 0.20 T) magnets, were similar to those obtained using an electromagnet with the same magnetic flux densities. The magnetic field strength and not the magnet type is important in controlling fluid flow, which is encouraging for integration of bonded permanent magnets into LOAC devices. 相似文献