全文获取类型
收费全文 | 1370篇 |
免费 | 53篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 10篇 |
化学工业 | 282篇 |
金属工艺 | 59篇 |
机械仪表 | 38篇 |
建筑科学 | 118篇 |
矿业工程 | 2篇 |
能源动力 | 65篇 |
轻工业 | 200篇 |
水利工程 | 4篇 |
石油天然气 | 4篇 |
无线电 | 62篇 |
一般工业技术 | 286篇 |
冶金工业 | 64篇 |
原子能技术 | 20篇 |
自动化技术 | 211篇 |
出版年
2023年 | 5篇 |
2022年 | 17篇 |
2021年 | 26篇 |
2020年 | 14篇 |
2019年 | 17篇 |
2018年 | 18篇 |
2017年 | 32篇 |
2016年 | 28篇 |
2015年 | 29篇 |
2014年 | 41篇 |
2013年 | 84篇 |
2012年 | 61篇 |
2011年 | 106篇 |
2010年 | 65篇 |
2009年 | 80篇 |
2008年 | 91篇 |
2007年 | 88篇 |
2006年 | 55篇 |
2005年 | 55篇 |
2004年 | 52篇 |
2003年 | 43篇 |
2002年 | 46篇 |
2001年 | 27篇 |
2000年 | 20篇 |
1999年 | 14篇 |
1998年 | 30篇 |
1997年 | 26篇 |
1996年 | 19篇 |
1995年 | 16篇 |
1994年 | 12篇 |
1993年 | 14篇 |
1992年 | 9篇 |
1991年 | 11篇 |
1990年 | 13篇 |
1989年 | 12篇 |
1988年 | 16篇 |
1987年 | 13篇 |
1986年 | 13篇 |
1985年 | 12篇 |
1984年 | 12篇 |
1983年 | 13篇 |
1982年 | 8篇 |
1981年 | 8篇 |
1980年 | 8篇 |
1979年 | 8篇 |
1978年 | 7篇 |
1976年 | 7篇 |
1974年 | 7篇 |
1973年 | 3篇 |
1972年 | 4篇 |
排序方式: 共有1425条查询结果,搜索用时 31 毫秒
991.
The protective effect of electrical stimulation and wrapping on beef tenderness at high pre rigor temperatures 总被引:1,自引:0,他引:1
Rosenvold K North M Devine C Micklander E Hansen P Dobbie P Wells R 《Meat science》2008,79(2):299-306
A three factorial experimental design involving electrical stimulation (ES/NES), wrapping (wrapped/unwrapped) and pre rigor temperature (15 °C or 35 °C) was applied to 70 beef M. longissimus lumborum muscles to obtain a wide variation in shear force and drip loss. The shear force of all treatment groups decreased during ageing. As anticipated, wrapping and electrical stimulation had positive effects on shear force. However, high pre rigor temperature (35 °C) did not result in higher shear force values if the muscles were electrically stimulated, wrapped or both. The results suggested that electrical stimulation protects against the negative effects of high pre rigor temperatures. The drip loss of all treatment groups increased during ageing in a manner that was unrelated to treatment but was correlated to tenderness (r2 = 0.70; p < 0.0001). It was concluded that the application of electrical stimulation, whatever the pre rigor temperature, protects beef from toughening through the prevention of rigor shortening and the avoidance of inhibition of ageing enzymes. 相似文献
992.
Development of a microfabricated optical bend loss sensor for distributive pressure measurement. 总被引:1,自引:0,他引:1
Wei-Chih Wang William R Ledoux Chu-Yu Huang Cheng-Sheng Huang Glenn K Klute Per G Reinhall 《IEEE transactions on bio-medical engineering》2008,55(2):614-625
A flexible high-resolution sensor capable of measuring the distribution of pressure beneath the foot via a microfabricated optical waveguide system is presented. The uniqueness of the system is in its batch fabrication process, which involves a microfabrication molding technique with polydimethylsiloxane (PDMS) as the optical medium. The sensor manufacturing technique is described in detail, the optical performance of the waveguides is quantified and the effect of using a matching fluid to improve fiber-coupling efficiency is demonstrated. Mechanical loading tests were performed on a 4 x 4 array with a 2-mm spacing between sensing elements. Loading displacement curves were obtained using a 0 to 0.4 mm triangle loading profile. A force of 0.28 N applied to one of the sensing elements produced a displacement of a 0.325 mm and 39% change in the output light intensity. Multiple loadings were conducted to demonstrate the repeatability of the sensor. A force image algorithm with a two-layer neural network system was used to identify four load magnitudes and four different shaped applicators. All four shapes were successfully identified with the neural network. 相似文献
993.
Suspension plasma spraying (SPS) has been shown as a promising process to produce porous columnar strain tolerant coatings for thermal barrier coatings (TBCs) in gas turbine engines. However, the highly porous structure is vulnerable to crack propagation, especially near the topcoat-bondcoat interface where high stresses are generated due to thermal cycling. A topcoat layer with high toughness near the topcoat-bondcoat interface could be beneficial to enhance thermal cyclic lifetime of SPS TBCs. In this work, a bilayer coating system consisting of first a dense layer near the topcoat-bondcoat interface followed by a porous columnar layer was fabricated by SPS using Yttria-stabilised zirconia suspension. The objective of this work was to investigate if the bilayer topcoat architecture could enhance the thermal cyclic lifetime of SPS TBCs through experiments and to understand the effect of the column gaps/vertical cracks and the dense layer on the generated stresses in the TBC during thermal cyclic loading through finite element modeling. The experimental results show that the bilayer TBC had significantly higher lifetime than the single-layer TBC. The modeling results show that the dense layer and vertical cracks are beneficial as they reduce the thermally induced stresses which thus increase the lifetime. 相似文献
994.
The measurement of similarity between objects plays a role in several scientific areas. In this article, we deal with document–document
similarity in a scientometric context. We compare experimentally, using a large dataset, first-order with second-order similarities
with respect to the overall quality of partitions of the dataset, where the partitions are obtained on the basis of optimizing
weighted modularity. The quality of a partition is defined in terms of textual coherence. The results show that the second-order
approach consistently outperforms the first-order approach. Each difference between the two approaches in overall partition
quality values is significant at the 0.01 level. 相似文献
995.
James Manuel Jae-Kwang Kim Aleksandar Matic Per Jacobsson Ghanshyam S. Chauhan Jong Keun Ha Kwon-Koo Cho Jou-Hyeon Ahn 《Materials Research Bulletin》2012,47(10):2815-2818
Polyaniline (PANI) was doped with different lithium salts such as LiPF6 and LiClO4 and evaluated as cathode-active material for application in room-temperature lithium batteries. The doped PANI was characterized by FTIR and XPS measurements. In the FTIR spectra, the characteristic peaks of PANI are shifted to lower bands as a consequence of doping, and it is more shifted in the case of PANI doped with LiPF6. The cathodes prepared using PANI doped with LiPF6 and LiClO4 delivered initial discharge capacities of 125 mAh g?1 and 112 mAh g?1 and stable reversible capacities of 114 mAh g?1 and 81 mAh g?1, respectively, after 10 charge–discharge cycles. The cells were also tested using polymer electrolyte, which delivered highest discharge capacities of 142.6 mAh g?1 and 140 mAh g?1 and stable reversible capacities of 117 mAh g?1 and 122 mAh g?1 for PANI-LiPF6 and PANI-LiClO4, respectively, after 10 cycles. The cathode prepared with LiPF6 doped PANI shows better cycling performance and stability as compared to the cathode prepared with LiClO4 doped PANI using both liquid and polymer electrolytes. 相似文献
996.
Guangyao Jin Per I. Widenborg Patrick Campbell Sergey Varlamov 《Progress in Photovoltaics: Research and Applications》2010,18(8):582-589
This paper examines the effectiveness of a range of aluminum induced textured (AIT) glass topographies at enhancing light absorption in silicon thin film diode structures deposited on the textured glass side, operating in the superstrate configuration. The aluminum layer used to produce the AIT can be deposited either by thermal evaporation or magnetron sputtering. Varying AIT process parameters produces a wide range of feature roughness and uniformity, providing scope to optimize texture effectiveness and process repeatability. We report strong correlation between the degree of absorption enhancement from these textures and both dark field microscope images of the AIT glass and reduction of the interference envelope in spectral reflectance of the deposited silicon films. Our findings corroborate earlier modeling work based on ray tracing, which predicted that the best enhancement occurs when the feature size is close to the film thickness. In this paper we investigate AIT samples in the 1 – 3 µm film thickness range, some of which trap light in silicon as strongly as at the Lambertian limit. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
997.
Martin Thuresson Magnus Själander Magnus Björk Lars Svensson Per Larsson-Edefors Per Stenstrom 《Journal of Signal Processing Systems》2009,57(1):5-19
We introduce FlexCore, the first exemplar of an architecture based on the FlexSoC framework. Comprising the same datapath units found in a conventional five-stage pipeline, the FlexCore has an exposed datapath control and a flexible interconnect to allow the datapath to be dynamically reconfigured as a consequence of code generation. Additionally, the FlexCore allows specialized datapath units to be inserted and utilized within the same architecture and compilation framework. This study shows that, in comparison to a conventional five-stage general-purpose processor, the FlexCore is up to 40% more efficient in terms of cycle count on a set of benchmarks from the embedded application domain. We show that both the fine-grained control and the flexible interconnect contribute to the speedup. Furthermore, according to our VLSI implementation study, the FlexCore architecture offers both time and energy savings. The exposed FlexCore datapath requires a wide control word. The conducted evaluation confirms that this increases the instruction bandwidth and memory footprint. This calls for efficient instruction decoding as proposed in the FlexSoC framework. 相似文献
998.
Christophe Lyphout Per Nylen Lars G?sta ?stergren 《Journal of Thermal Spray Technology》2012,21(1):86-95
The adhesion strength of high-velocity oxyfuel thermally sprayed coatings is of prime importance when thick coatings are to
be sprayed in repair applications. In this study, relationships between process parameters, particle in-flight characteristics,
residual stresses, and adhesion strength were explored. The most important process parameters that influence HVOF sprayed
IN718 coating adhesion strength on IN718 substrate material were identified. Residual stress distributions were determined
using the modified layer removal method, and adhesion strength was measured using an in-house-developed tensile test. Relationships
between process parameters, particle in-flight characteristics, coating microstructure, and adhesion strength were established.
Particle temperature, particle velocity, substrate preparation, and deposition temperature were identified as critical parameters
to attain high adhesion strength. Controlling these parameters can significantly improve the adhesion strength, thus enabling
thick coatings to be sprayed for repair applications. 相似文献
999.
The aim of this study is to relate the influence of ground water to the properties of bentonite gels. It has been proposed that compacted bentonite could be used as a buffer substance around canisters containing nuclear waste deposited about 500 m down in the bedrock. The bentonite shield is thought to provide a zone of low permeability which on contact with ground water will swell into cracks formed in the rock.Visual inspection and measurements of the amount of particles released from a bentonite gel by light-scattering showed that while particles are released in distilled water, they are coagulated when in contact with ground water with composition varying within reasonable limits, with the result that the release of particles is negligibly small.Studies of sedimentation volumes after ultracentrifugation also clearly indicated that the bentonite in contact with ground water in the repository forms a completely coagulated gel.It was shown that calcium ions diffuse rapidly into the gel that is in contact with ground water. This implies that bentonite gel which is initially partially in its sodium form will be completely exchanged to its calcium form when brought into contact with ground water. This ensures that it remains coagulated and does not release any particles. 相似文献
1000.
Per Brinch Hansen 《Software》1976,6(2):165-200
This paper describes the implementation of the Solo operating system written in Concurrent Pascal.* It explains the overall structure and details of the system in which concurrent processes communicate by means of a hierarchy of monitors and classes. The concurrent program is a sequence of nearly independent components of less than one page of text each. The system has been operating since May 1975. 相似文献