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41.
Mirko Kariz Manja Kitek Kuzman Milan Sernek Mark Hughes Lauri Rautkari Frederick A. Kamke Andreja Kutnar 《Holz als Roh- und Werkstoff》2017,75(1):113-123
Spruce (Picea abies L. Karst) wood lamellae, thermally treated at 170, 190, 210 and 230 °C were surface densified by compression at a temperature of 150 °C to three degrees of compression. Immediate springback, set recovery, mechanical properties in 3-point flexure, Brinell hardness and density profiles measurements were used to determine the effect of thermal treatment on the properties of surface densified wood. The highest immediate springback occurred in wood specimens thermally treated at the highest temperature (230 °C) and decreased with decreasing thermal treatment temperature. The untreated samples had the highest set recovery, which decreased with the temperature of thermal treatment. The surface densification increased hardness and bending strength. The highest increase was in the case of untreated wood and decreased with the temperature of thermal treatment. The modulus of elasticity (MOE) and modulus of rupture (MOR) of surface densified wood decreased with increasing thermal treatment temperature. The trend was similar for specimens which were thermally treated but not surface densified. Surface densification increased the density of the specimens in the first few millimetres below the surface. The highest density was achieved in untreated specimens and the lowest in specimens thermally treated at the highest temperature. 相似文献
42.
Steerable miniature jumping robot 总被引:2,自引:0,他引:2
Mirko Kovač Manuel Schlegel Jean-Christophe Zufferey Dario Floreano 《Autonomous Robots》2010,28(3):295-306
Jumping is used in nature by many small animals to locomote in cluttered environments or in rough terrain. It offers small
systems the benefit of overcoming relatively large obstacles at a low energetic cost. In order to be able to perform repetitive
jumps in a given direction, it is important to be able to upright after landing, steer and jump again. In this article, we
review and evaluate the uprighting and steering principles of existing jumping robots and present a novel spherical robot
with a mass of 14 g and a size of 18 cm that can jump up to 62 cm at a take-off angle of 75°, recover passively after landing,
orient itself, and jump again. We describe its design details and fabrication methods, characterize its jumping performance,
and demonstrate the remote controlled prototype repetitively moving over an obstacle course where it has to climb stairs and
go through a window. (See videos 1–4 in the electronic supplementary material.) 相似文献
43.
Mirko Rahn 《Information Processing Letters》2008,106(3):115-119
We present a new technique to decide or reduce instances of Post's correspondence problem. It generalizes balance arguments to a consideration about some special context-free languages which allow the combination with other decision (or reduction) techniques. In spite of its simplicity, the new technique is able to decide more instances than known techniques. 相似文献
44.
In light of IASB??s statement to drop stewardship as a separate objective of financial accounting and the ongoing debate about increasing the disclosure of soft information, we investigate the economic consequences of publicly reported soft information from a stewardship perspective. In an LEN model we include market price as a performance measure and investigate whether the principal benefits from disclosing additional information. While the principal can only use contractible performance measures in the contract with the agent, capital market participants can only use disclosed information when pricing firm value. We find that the disclosure of information can decrease the principal??s expected net profit. This result follows from either a noisier or a less congruent market price as a consequence of disclosing additional information. Thus, we present a rationale for partial disclosure in the absence of proprietary costs or the uncertainty of information endowment. 相似文献
45.
Saskia van Ruth Martin Alewijn Karyne Rogers Elizabeth Newton-Smith Noelia Tena Mirko Bollen Alex Koot 《Food chemistry》2011
Organic production benefits from fair competition and sustained consumer confidence. The latter can only be assured by paper trailing and verification assessments. Traditional analytical strategies for guaranteeing quality and uncovering adulteration have relied on the determination of the amount of a marker compound or compounds in a material and a subsequent comparison of the value(s) obtained with those established for equivalent material. Since it is unlikely to find a unique marker that allows discrimination between organic and conventional produce, selective fingerprinting (profiling) combined with chemometrics is a more promising approach. In this study, carotenoid High Performance Liquid Chromatography–Diode Array Detection profiling combined with k-nearest neighbour classification chemometrics was used to predict the production system (organic vs. non-organic) of chicken eggs. A proof-of-concept set (training set for the model) was composed of eggs from 24 organic farms, 12 free range, and 12 barn farms in the Netherlands. The identities of organic, free range, and barn eggs were predicted with success rates of 100%, 100%, and 84%, respectively. The identity of eggs determined using an additional market test set with eggs from 12 organic, 12 free range, and 12 barn farms originating from the Netherlands and New Zealand resulted in correct classifications for 35 of the 36 samples. The results of this study indicate that this fingerprint approach is a promising tool for analytical verification of the production system of organic eggs. 相似文献
46.
A fully sealed luminescent tube of 40 cm length and 4 cm diameter based on carbon nanotube field emission is demonstrated. The device shows a homogeneous illumination over the whole length and circumference of the tube and reaches the luminance of conventional fluorescent tubes while being mercury-free, continuously dimmable and with a high illuminance capability. The realization has been made possible with the development of a chemical vapor deposition method to grow nanotubes homogeneously on long metallic wires, which provides an additional possibility to control the mean length and density of the emitters. This control has proven to be of utmost importance as it makes possible to adjust the emission voltage and emission site density needed to reach the target intensity and specifications of the device. 相似文献
47.
48.
Effect of polymorphic phase transformations in Al2O3 film on oxidation kinetics of aluminum powders 总被引:1,自引:0,他引:1
Mikhaylo A. Trunov Mirko Schoenitz Xiaoying Zhu Edward L. Dreizin 《Combustion and Flame》2005,140(4):310-318
Thermogravimetry was used to study the oxidation of aluminum powders at elevated temperatures. Aluminum powders of various particle sizes and surface morphologies were heated in oxygen up to 1500 °C at different heating rates. Partially oxidized samples were recovered from selected intermediate temperatures and the oxide phases present were analyzed by X-ray diffraction. The experimental data were related to current information on stabilities and phase changes of Al2O3 polymorphs. Aluminum powders were observed to oxidize in four distinct stages in the temperature range from 300 to 1500 °C. During stage I, from 300 to about 550 °C, the thickness of the natural amorphous alumina layer on the particle surface increases. The rate of this process is controlled by the outward diffusion of Al cations. At about 550 °C, when the oxide layer thickness exceeds the critical thickness of amorphous alumina of about 4 nm, the oxide transforms into γ-Al2O3. The specific volume of γ-Al2O3 is less than that of amorphous alumina; therefore, the newly formed γ-Al2O3 only partially covers the aluminum surface. The oxidation rate increases rapidly at the onset of stage II, but it decreases when the γ-Al2O3 layer becomes continuous. During stage III oxidation, the γ-Al2O3 layer grows and partially transforms into the structurally similar θ-Al2O3 polymorph. Finally, oxidation stage IV is observed after the transition to stable -Al2O3 results in an abrupt reduction of oxidation rate. Qualitative analysis of the rates of oxidation at the different stages enables one to understand the wide range of aluminum ignition temperatures observed for particles of different sizes. 相似文献
49.
Mirko Křivánek 《Pattern recognition letters》1985,3(5):299-301
The technique of limited branching is used to answer an open problem of P. Brucker (1977) arising in a study of computational complexity of clustering problems. This problem is shown to be solvable by a polynomial algorithm. 相似文献
50.
Ljubomir Vajda Milan Verĉon Elena Vuĉetiĉ Smilja Dzakoviĉ Radivoe Eftimiades Božidar Jovanoviĉ Aleksandr Konstantinoviĉ Dejan Mandiĉ Melentieviĉ Mirko Vlastimir Puriĉ Bratislav Subbanoviĉ Josif Hvoj Miodrag Coroviĉ 《Power Technology and Engineering (formerly Hydrotechnical Construction)》1969,3(6):578-579