全文获取类型
收费全文 | 970篇 |
免费 | 27篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 46篇 |
化学工业 | 299篇 |
金属工艺 | 23篇 |
机械仪表 | 48篇 |
建筑科学 | 11篇 |
能源动力 | 26篇 |
轻工业 | 33篇 |
水利工程 | 3篇 |
石油天然气 | 2篇 |
无线电 | 71篇 |
一般工业技术 | 194篇 |
冶金工业 | 154篇 |
原子能技术 | 25篇 |
自动化技术 | 66篇 |
出版年
2023年 | 3篇 |
2022年 | 18篇 |
2021年 | 21篇 |
2020年 | 11篇 |
2019年 | 10篇 |
2018年 | 15篇 |
2017年 | 18篇 |
2016年 | 13篇 |
2015年 | 15篇 |
2014年 | 19篇 |
2013年 | 36篇 |
2012年 | 33篇 |
2011年 | 42篇 |
2010年 | 36篇 |
2009年 | 34篇 |
2008年 | 46篇 |
2007年 | 45篇 |
2006年 | 33篇 |
2005年 | 42篇 |
2004年 | 25篇 |
2003年 | 23篇 |
2002年 | 17篇 |
2001年 | 19篇 |
2000年 | 15篇 |
1999年 | 22篇 |
1998年 | 67篇 |
1997年 | 54篇 |
1996年 | 26篇 |
1995年 | 25篇 |
1994年 | 26篇 |
1993年 | 23篇 |
1992年 | 12篇 |
1991年 | 19篇 |
1990年 | 12篇 |
1989年 | 19篇 |
1988年 | 5篇 |
1987年 | 12篇 |
1986年 | 5篇 |
1985年 | 16篇 |
1984年 | 13篇 |
1983年 | 8篇 |
1982年 | 7篇 |
1981年 | 8篇 |
1980年 | 2篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1977年 | 8篇 |
1976年 | 7篇 |
1975年 | 3篇 |
1966年 | 2篇 |
排序方式: 共有1001条查询结果,搜索用时 15 毫秒
71.
Takashi Wakuda Kazuo Azuma Hiroyuki Saimoto Shinsuke Ifuku Minoru Morimoto Ichiro Arifuku Masahito Asaka Takeshi Tsuka Tomohiro Imagawa Yoshiharu Okamoto Tomohiro Osaki Saburo Minami 《Journal of Functional Foods》2013,5(1):516-523
The effects of pear vinegar (PV), which was specially brewed for enhanced galacturonic acid content, on the DSS-induced ulcerative colitis (UC) mouse model were evaluated. PV improved clinical symptoms, colon inflammation, and histological tissue injury in the DSS-induced acute UC mouse model. Moreover, PV suppressed inflammation due to acute UC by suppressing the myeloperoxidase (MPO)-mediated activation of inflammatory cells such as leukocytes and decreasing the serum concentration of IL-6. Our results demonstrated the protective action of PV in the DSS-induced acute UC mouse model. On the other hand, commercial apple vinegar did not show a protective effect in the DSS-induced acute UC mouse model. Our findings indicate that PV may act as a new functional food for inflammatory bowel disease patients. 相似文献
72.
Mizuki Tsuta Yasuhiko Sasaki Ikuo Takeuchi Hideki Nakamoto Jun Ishikawa Susumu Kawasaki Junichi Sugiyama Kaori Fujita Masatoshi Yoshimura Mario Shibata Mito Kokawa 《LWT》2014
Flow cytometry (FCM) and aerobic plate count (APC) by the culture method were performed on green tea samples spiked with Escherichia coli type strain NCTC9001 (ATCC11775) solutions of different concentrations. In FCM, fluorescence signals from multiple stained bacteria and other fluorophores are detected using detector channels, and recorded as events with a voltage at each channel. FCM data were analyzed in two ways: conventional and multivariate analysis. In the former, the number of events with voltages larger than the defined threshold values was regarded as the predicted APC. In the latter, voltage histograms of all channels were obtained and merged horizontally to serve as explanatory variables. Then a partial least squares regression (PLSR) model was built to predict APC from the histogram data. The coefficient of determination (R2) and the root mean square error (RMSE) between APC by the culture method and that predicted by conventional FCM were 0.916 and 1.08 cfu/ml2. The APC values predicted by the PLSR model and those measured were in good agreement with R2 of 0.982 and RMSE of 0.417 cfu/ml, which verified the potential of the proposed method for improving APC prediction accuracy by FCM. 相似文献
73.
Masaki Oiwa Shunsuke Minami Kenichiro Tsuji Noriaki Onodera Masatoshi Saruwatari 《Optical Fiber Technology》2010,16(1):63-71
We propose and experimentally demonstrate the temporal-Talbot-effect (TTE)-based preprocessing for the pattern-effect reduction in the all-optical clock recovery using a semiconductor-optical-amplifier (SOA)-based fiber ring laser (SOA-FRL). The TTE-based preprocessing successfully reduced the pattern effects of the recovered clock pulses, so that the 10-GHz clear optical clock pulses were recovered from a 10-Gbit/s return-to-zero on–off keying (RZ-OOK) pseudo-random bit sequence (PRBS) optical signal. “Peak variation” and “Pattern-dependent intensity noise (PDIN)” were proposed and were utilized as parameters to quantitatively evaluate the pattern effects, from which recovered clock pulses suffer, in the temporal domain and the frequency domain, respectively. Peak variation was reduced from 77.2% to 36.2%, and PDIN was improved from ?103 dBc/Hz to ?110 dBc/Hz with the aid of the TTE-based preprocessing. Furthermore, we examined the tolerance of the proposed technique by intentionally deviating the input signal’s bit-rate by ±190 Mbit/s (±2% of the bit-rate) from the optimum condition for the TTE. As compared with the PDIN value for the pulse train obtained by the direct injection of the non-processed signal into the SOA-FRL, the PDIN of the recovered clock pulses using the preprocessed signal indicated improvements over the entire measurement range of ±190 Mbit/s, which corresponds to the wavelength-dispersion deviation of ±56 ps/nm (±4% of the wavelength-dispersion applied to the input signal) from the optimum value. 相似文献
74.
Three diamensional (3D) measurement method by Scanning Electron Microscope (SEM) has already been proposed by using the principle
of shadow moiré. In the method, the image of original grid in shadow moiré image must be clearly removed in fringe analysis
process in order to perform high resolution analysis. A new method based on the principle of projection moiré is proposed
to solve the trouble concerning the grid. In this paper, the mechanism of producing some shadows of grid on the surface of
the object by back scattering electron beam in the new method is discussed. Fringe image as shadow of grid is analyzed by
Wavelet transform. The precise 3D measurement is realized by using the phenomenon of shadows of grid. Furthermore, a 3D micro
structure on the head of a hard disk is measured. From the comparison of results obtained by Atomic Force Microscope (AFM),
it is confirmed that the proposed method has high-resolution power(about 20nm). 相似文献
75.
Kazuya Aida Yasuhiko Benino Vesselin Dimitrov Takayuki Komatsu Ryuji Sato 《Journal of the American Ceramic Society》2000,83(5):1192-1198
The kinetics of enthalpy relaxation (recovery) at the glass transition in x K2 O·(20− x )MgO·80TeO2 glasses has been examined from heat capacity measurements using differential scanning calorimetry to clarify the features of the structural relaxation in ternary TeO2 -based glasses. Ternary glasses such as 10K2 O·10MgO·80TeO2 show high thermal resistance against crystallization compared with binary glasses. The degree of fragility m estimated from the activation energy for viscous flow E η and the glass transition temperature T g is m = 55–62, indicating a fragile character in TeO2 -based glasses. Large heat capacity changes of 43.1–48.2 J·mol−1 ·K−1 are also observed at the glass transition. The activation energy for enthalpy relaxation Δ H is evaluated from the cooling rate dependence of the limiting fictive temperature, and values of Δ H = 897–1268 kJ·mol−1 are obtained. Negative deviation from additivity in Δ H is also observed. Values of the Kovacs–Aklonis–Huchinson–Ramos (KAHR) parameter θ estimated from Δ H and T g are 0.33–0.42 K−1 . It has been proposed that ternary glasses have more homogeneous and constrained glass structure compared with binary glasses. 相似文献
76.
Modeling of NBTI saturation effect and its impact on electric field dependence of the lifetime 总被引:1,自引:0,他引:1
H. Aono E. Murakami K. Okuyama A. Nishida M. Minami Y. Ooji K. Kubota 《Microelectronics Reliability》2005,45(7-8):1109-1114
Negative Bias Temperature Instability of pMOSFETs is investigated under various stress gate voltages and temperatures. It is shown that degradation tends to saturate and the dependence of lifetime on electric field (Eox) is expressed as a power-law of Eox. We propose new empirical and kinetic models. The Eox dependence of the lifetime described by the power-law is derived from our empirical model describing the saturation of degradation. Moreover, our kinetic model explains the saturation behavior. 相似文献
77.
In 1996, the authors proposed a novel method to prepare micron-sized, hollow cross-linked polymer particles. This method is based on the self-assembling of phase separated polymer at interface with water, which was named SaPSeP method, formed by suspension polymerization of divinyl monomer in toluene droplet dissolving previously polystyrene. The SaPSeP method was developed to be applicable to polyaddition reaction system of epoxy resin with diamine. The presence of PS dissolving in epoxy/diamine/toluene droplets promotes the phase separation of the epoxy resin reacted with the diamine. The epoxy resin molecules tend to adsorb at the interface of the droplets. These points were accord with the required conditions for the preparation of hollow particle by the SaPSeP method. Cured epoxy resin particles having one hollow were successfully prepared by the polyaddition reaction in the dispersed system of Epikote 806/630/604, of which equivalent ratio was 5/4/1. 相似文献
78.
79.
Bruce A. Julian Hitoshi Suzuki Goce Spasovski Yusuke Suzuki Yasuhiko Tomino Jan Novak 《Proteomics. Clinical applications》2009,3(9):1023-1028
Chronic kidney disease accounts for a significant portion of many national health-care budgets. In this viewpoint, we highlight recent advances in urinary proteomic analyses that potentially may soon enhance the care of afflicted patients. To achieve this goal, cooperation of interdisciplinary teams from around the world will be vital, so as to standardize methodology for preparation urine samples and technical aspects of the analyses, and for better application of results. These collaborative activities will facilitate translational research in kidney diseases. 相似文献
80.
M. Cai P.K. Kaiser H. Morioka M. Minami T. Maejima Y. Tasaka H. Kurose 《International Journal of Rock Mechanics and Mining Sciences》2007,44(4):550-564
Acoustic emission (AE) and microseismic (MS) events are indicators of rock fracturing or damage as the rock is brought to failure at high stress. By capturing the AE/MS events, underground excavation induced rock mass degradation or damage can be located and evaluated. A better understanding of the extent and shape of the excavation damaged zone (EDZ) or yield zone around caverns helps to arrive at safe and economic design and construction of the caverns. For this purpose, one needs to understand the AE mechanism associated with the excavation process.In the present study, a coupled numerical method is used to study AE at the Kannagawa underground powerhouse cavern in Japan. Two codes, Fast Lagrangian Analysis of Continua (FLAC), a finite difference code and Particle Flow Code (PFC), a distinct element code, are coupled. The motive to apply the FLAC/PFC coupled approach is to take advantage of each modeling scheme while at the same time minimizing the requirement for computational resources. The coupling is realized through an exchange of displacements, velocities, and forces in each cycling step. The rock mass surrounding an AE sensor is modeled using PFC and the remaining rock mass is modeled with FLAC to consider the geological complexity and the excavation sequence. In this manner, the AE activities at AE sensor locations of the Kannagawa cavern were simulated and found to be in good agreement with field monitoring results. This approach takes account of stress redistribution and provides stress and displacement patterns in the rock mass that are consistent with AE observations for excavation design. The observed AE activities in the rock mass can thus be utilized to assess the effectiveness of the rock support system and the overall stability of the cavern. 相似文献