全文获取类型
收费全文 | 873篇 |
免费 | 21篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 69篇 |
综合类 | 3篇 |
化学工业 | 194篇 |
金属工艺 | 17篇 |
机械仪表 | 14篇 |
建筑科学 | 25篇 |
矿业工程 | 1篇 |
能源动力 | 50篇 |
轻工业 | 61篇 |
无线电 | 54篇 |
一般工业技术 | 186篇 |
冶金工业 | 62篇 |
原子能技术 | 38篇 |
自动化技术 | 123篇 |
出版年
2023年 | 4篇 |
2022年 | 7篇 |
2021年 | 20篇 |
2020年 | 11篇 |
2019年 | 13篇 |
2018年 | 18篇 |
2017年 | 15篇 |
2016年 | 15篇 |
2015年 | 15篇 |
2014年 | 24篇 |
2013年 | 46篇 |
2012年 | 43篇 |
2011年 | 78篇 |
2010年 | 48篇 |
2009年 | 40篇 |
2008年 | 60篇 |
2007年 | 43篇 |
2006年 | 40篇 |
2005年 | 29篇 |
2004年 | 28篇 |
2003年 | 25篇 |
2002年 | 34篇 |
2001年 | 14篇 |
2000年 | 12篇 |
1999年 | 9篇 |
1998年 | 20篇 |
1997年 | 18篇 |
1996年 | 15篇 |
1995年 | 17篇 |
1994年 | 21篇 |
1993年 | 18篇 |
1992年 | 7篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 13篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 7篇 |
1984年 | 8篇 |
1983年 | 8篇 |
1982年 | 6篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1973年 | 3篇 |
1972年 | 2篇 |
排序方式: 共有897条查询结果,搜索用时 62 毫秒
91.
92.
Tetraphenylethylene (TPE) derivatives have strong fluorescence in aggregated state. We report here an oligosaccharide binding assay system using tetraphenylethylene derivatives bearing oligosaccharides with aggregation-induced emission (AIE) characteristics. A tetraphenylethylene derivative bearing 6'-sialyllactose (6'SL) bound to microbeads coated with SSA lectin more effectively than RCA120 lectin. Microbeads that bound to fluorescent oligosaccharide probes could be detected by flow cytometric analysis. Tetraphenylethylene derivatives bearing oligosaccharides are useful for flow cytometric analysis of lectin-oligosaccharide interactions. 相似文献
93.
Hashimoto S Nishimura K Takahashi K Itabashi Y 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2011,52(3):194-198
Midgut glands of bivalves are used for the mouse bioassay of diarrhetic shellfish poison (DSP). A large quantity of free fatty acids (FFAs) causes a false positive outcome in the assay. To examine whether this is likely to occus under conditions of actual use, we analyzed the contents of the FFAs in the enlarged midgut glands during gametogenesis of Japanese scallops Patinopecten yessoensis that had been caught at two points in Hunka Bay on March 27, 2006, because the content of FFAs may increase with activation of lipogenesis for gametogenesis. Fatty acids (FAs) were measured with fluorometric high-performance liquid chromatography after derivatization with 9-anthryldiazomethane. The total FFAs (14 : 0, 16 : 0, 18 : 0, 16 : 1, 18 : 1, 18 : 4, 20 : 5 and 22 : 6) represented 3.3-4.2 wt% of the lipid. The toxic FFAs accounted for 40-43 wt% of the total FFAs. Content of each FFA (18 : 1, 2.7-5.0 mg/g lipid; 18 : 4, tr.-2.0 mg/g; 20 : 4, n.d.; 20 : 5, 8.0-9.1 mg/g and 22 : 6, 2.0-2.1 mg/g) was lower than the lethal dose tentatively calculated from the relative toxicity. It appears that the likelihood of FFAs causing false-positives in the mouse bioassay is low if the sample is fresh and is extracted immediately after homogenizing. 相似文献
94.
Tahara T Ito K Kakue T Fujii M Shimozato Y Awatsuji Y Nishio K Ura S Kubota T Matoba O 《Applied optics》2011,50(7):B31-B37
We propose an algorithm for compensating the phase-shift error of polarization-based parallel two-step phase-shifting digital holography, which is a technique for recording a spatial two-step phase-shifted hologram. Although a polarization-based system of the technique has been experimentally demonstrated, there had been the problem that the phase difference of two phase-shifted holograms had been changed by the extinction ratio of the micropolarizer array attached to the image sensor used in the system. To improve the performance of the system, we established and formulated an algorithm for compensating the phase-shift error. Accurate spatial phase-shifting interferometry in the system can be conducted by the algorithm regardless of phase-shift error due to the extinction ratio. By the numerical simulation, the proposed algorithm was capable of reducing the root mean square errors of the reconstructed image by 1/4 and 1/5 in amplitude and phase, respectively. Also, the algorithm was experimentally demonstrated, and the experimental results showed that the system employing the proposed algorithm suppressed the conjugate image, which slightly appeared in the image reconstructed by the system not employing the algorithm, even when the extinction ratio was 10:1. Thus, the effectiveness of the proposed algorithm was numerically and experimentally verified. 相似文献
95.
96.
Toshikazu Hori Yoshiyuki Mohri Yuji Kohgo Kenichi Matsushima 《Soils and Foundations》2011,51(1):53-66
Failures of earth dam embankments and river dikes, which are constructed of sandy soils with low dry densities, have been observed to occur during rising of water levels. In this paper, a large-scale physical model test was conducted in order to investigate the behavior of a small dam embankment as water levels rose. The test results were simulated by use of a consolidation analysis method coupled with an elastoplastic model for unsaturated soils. All parameters used in the simulation were obtained from element tests; oedometer, triaxial compression, soil water retention, and permeability tests. First, in order to verify the parameters identified, direct shear tests were simulated using the consolidation analysis method; results of the simulation and the tests were consistent. From the embankment model test it was found that the crest of the embankment moved upstream at the first stage of impounding and then moved back. After a seepage surface appeared on the downstream slope, tension cracks occurred on the downstream slope, and sliding occurred through the crack and the downstream toe. The results of the simulation were consistent with those of the model test. This consolidation analysis method could be used to simulate the complex deformations induced by saturation collapse and shear strains and even failure behavior. Old embankments constructed with loose densities might have histories in which cracks occurred on the downstream slopes when the reservoir water level rose, and their stabilities might have decreased. 相似文献
97.
Okabe M. Okuno Y. Arakawa T. Tomioka I. Ohno T. Noda T. Hatanaka M. Kuramitsu Y. 《Solid-State Circuits, IEEE Journal of》1989,24(5):1280-1286
A 0.8- mu m CMOS sea-of-gates (SOG) array with first-level wiring channels perpendicular to transistor rows and 40 0K transistors is integrated on a 6*7-mm/sup 2/ chip. Implementation of a 64-bit multiplier shows 60-percent gate utilization and density of 1410 G/mm/sup 2/. The wiring length of the multiplier is 70 percent of that in a conventional SOG.<> 相似文献
98.
Solving fuzzy shortest path problems by neural networks 总被引:1,自引:0,他引:1
In this paper, we introduce the neural networks for solving fuzzy shortest path problems. The penalization of the neural networks is realized after transforming into crisp shortest path model. The procedure and efficiency of this approach are shown with numerical simulations. 相似文献
99.
Manabu Oishi Yukihisa Matsuda Kenichi Noguchi Takaki Masaki 《Journal of the American Ceramic Society》1995,78(5):1212-1216
The tensile strength of yttria-stabilized tetragonal zirconia polycrystals (Y-TZPs) was measured and the fracture surfaces were analyzed with the scanning electron microscope and X-ray microanalyzer. The fracture origins of the pressureless-sintered samples were voids or inclusions such as A12 O3 , A12 O3 with SiO2 , and cubic-ZrO2 , while the fracture origins of the hot isostatically pressed samples were inclusions; no voids were detected at fracture origins. The higher strengths of the hot isostatically pressed samples versus those of the pressureless-sintered samples were consistent with the change in fracture origins. The fracture toughness of the samples calculated from the tensile strength and analysis of the fracture origins was 3.4 to 3.7 MPa √m. These values are lower than those measured with the SEPB method. These discrepancies might be caused by the difference in the state of the fracture origin and its neighborhood, such as the size of the fracture origin and interaction between two surfaces in the precrack. 相似文献
100.
This paper describes realtime network management support systems which have been developed forntt’s telephone network. In particular, the advanced traffic observation and management information collecting system referred to as Atomics and the traffic congestion control system referred to astcs are presented. The purpose of the development, concept, functions and capabilities of each system are explained. Examples of powerful realtime network management supported by Atomics andTSC are also presented. 相似文献