全文获取类型
收费全文 | 1413篇 |
免费 | 41篇 |
国内免费 | 6篇 |
学科分类
工业技术 | 1460篇 |
出版年
2023年 | 8篇 |
2022年 | 22篇 |
2021年 | 37篇 |
2020年 | 18篇 |
2019年 | 21篇 |
2018年 | 20篇 |
2017年 | 26篇 |
2016年 | 25篇 |
2015年 | 27篇 |
2014年 | 33篇 |
2013年 | 71篇 |
2012年 | 62篇 |
2011年 | 67篇 |
2010年 | 59篇 |
2009年 | 55篇 |
2008年 | 56篇 |
2007年 | 47篇 |
2006年 | 42篇 |
2005年 | 45篇 |
2004年 | 26篇 |
2003年 | 41篇 |
2002年 | 27篇 |
2001年 | 29篇 |
2000年 | 19篇 |
1999年 | 33篇 |
1998年 | 139篇 |
1997年 | 94篇 |
1996年 | 50篇 |
1995年 | 28篇 |
1994年 | 43篇 |
1993年 | 36篇 |
1992年 | 17篇 |
1991年 | 10篇 |
1990年 | 7篇 |
1989年 | 11篇 |
1988年 | 8篇 |
1987年 | 9篇 |
1986年 | 10篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 10篇 |
1982年 | 4篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1978年 | 5篇 |
1977年 | 8篇 |
1976年 | 12篇 |
1975年 | 5篇 |
1974年 | 3篇 |
1973年 | 6篇 |
排序方式: 共有1460条查询结果,搜索用时 15 毫秒
81.
Cooling load is a heat value of cold water used for air conditioning in a district heating and cooling system. Cooling load prediction in a district heating and cooling system is one of the key techniques for smooth and economical operation. In this article, cooling load prediction in such a district heating and cooling system is considered. Unfortunately, since actual cooling load data usually involve measurement noises, outliers, and missing data for several reasons, a prediction method considering the effect of the outliers and missing data is desirable. In this article, a new prediction method using a simplified robust filter to improve a numerical stability problem of a robust filter and a three-layered neural network, is proposed. Applications of the proposed method and some other methods to actual cooling load data in a district heating and cooling system involving outliers and missing data show the usefulness of the proposed method. 相似文献
82.
Kenji Fukuzawa Hiroaki Tsuji Satoshi Hamaoka Mitsuhiro Shikida Shintaro Itoh Hedong Zhang 《Microsystem Technologies》2013,19(9-10):1567-1572
It is important to understand friction force in micro/nano mechanical devices both at high sliding speed and with high lateral resolution. Dual-axis friction force microscopes that can provide high lateral resolution and accuracy have been proposed; however, the sliding speed is limited by the probe scan speed. While a micro mechanical probe (MMP) with an electrostatic actuator can overcome this problem, details of probe design have not been established yet. This paper presents the principle of the mechanical design for an MMP with high force sensitivity and sufficient drive force. The dimensions of the double cantilever beam control the spring constants, resonant frequencies, and drive force. The use of an actuated MMP enables accurate friction force microscopy at high sliding speeds, which is required for the design of micro/nano mechanical devices. 相似文献
83.
84.
Kosuke Aiuchi Ryo Moriyama Shohei Takeda Shunji Kitada Masaki Onozaki Yukuo Katayama 《Fuel Processing Technology》2007
A pre-heating vaporization technology of coal water slurry, CWS, was developed to increase the efficiency of coal gasification with the reduction of oxygen consumption. A CWS pre-heating experimental unit having a capacity of 2.0 tons-coal/day was manufactured. After the CWS was heated to 573 K at about 10 MPa, water in CWS was continuously vaporized in a tube of which the diameter increased gradually (2–10 mm I.D.), and dry coal particles with steam were atomized and fed to a vessel. No aggregation of coal particles was observed in the atomized samples. The temperature and the pressure distributions of the fluid were calculated with empirical heat transfer and pressure drop correlations. The calculated results well corresponded to the experimental data measured in some test points. Using the calculation model, a large scale apparatus of 100 tons-coal/day was designed using KNO3 + NaNO2 + NaNO3 molten salt as a heating medium. 相似文献
85.
Yuya Hattori Michiyo Suzuki Zu Soh Yasuhiko Kobayashi Toshio Tsuji 《Artificial Life and Robotics》2012,17(2):173-179
The pharyngeal pumping motion to send food to the bowel is a rhythmic movement in Caenorhabditis elegans. This paper proposes a simulation-based approach to investigate the mechanisms of rhythm phenomena in the pharyngeal pumping motion. To conduct the simulations, first, we developed a pharyngeal muscle model including 29 cell models which simulate the activity of each cell as a membrane potential based on FitzHugh-Nagumo equations. Then, to compare the response of the model with that of C. elegans, we calculated the electropharyngeogram (EPG), which represents the electrophysiological responses of the pharyngeal cells, using the simulated membrane potentials. The results confirmed that our model could generate the EPG similar to that measured from C. elegans. We proposed a computer simulation of the pumping motion to investigate the mechanisms of rhythm phenomena in living organisms. 相似文献
86.
Detection of Verotoxigenic Escherichia coli O157 and O26 in food by plating methods and LAMP method: a collaborative study 总被引:3,自引:0,他引:3
Hara-Kudo Y Konishi N Ohtsuka K Hiramatsu R Tanaka H Konuma H Takatori K 《International journal of food microbiology》2008,122(1-2):156-161
In order to establish a rapid and sensitive method for the detection of Verotoxigenic Escherichia coli O157 and O26, a collaborative study was conducted focusing on a comparison of the efficiency of loop-mediated amplification (LAMP) assay targeting the Verocytotoxin (also called Shiga toxin) gene, utilizing a direct plating method and a plating method with immunomagnetic separation (IMS-plating method) using various agar media. In combination with enrichment with the modified EC supplemented with novobiocin, E. coli O157 was detected in most samples of ground beef and alfalfa sprouts by LAMP assay, the direct plating method and the IMS-plating method. E. coli O26 was detected in approximately 100% of the food samples by LAMP assay. However, the IMS-plating and direct plating methods recovered 80 and 50% in ground beef samples, respectively. As a result, it was demonstrated the LAMP assay is superior to the IMS-plating method. Based on these results, it appears LAMP assay is effective as a screening assay to detect E. coli O157 and O26 from positive samples. 相似文献
87.
Zengyun Jian Kosuke Nagashio Kazuhiko Kuribayashi 《Metallurgical and Materials Transactions A》2002,33(9):2947-2953
Using an electromagnetic levitation facility with a laser heating unit, silicon droplets were highly undercooled in the containerless
state. The crystal morphologies on the surface of the undercooled droplets during the solidification process and after solidification
were recorded live by using a high-speed camera and were observed by scanning electron microscopy. The growth behavior of
silicon was found to vary not only with the nucleation undercooling, but also with the time after nucleation. In the earlier
stage of solidification, the silicon grew in lateral, intermediary, and continuous modes at low, medium, and high undercoolings,
respectively. In the later stage of solidification, the growth of highly undercooled silicon can transform to the lateral
mode from the nonlateral one. The transition time of the sample with 320 K of undercooling was about 535 ms after recalescence,
which was much later than the time where recalescence was completed. 相似文献
88.
Hiroki Ago Naoyasu Uehara Masaharu Tsuji Motoo Yumura Toshihiko Setoguchi 《Carbon》2006,44(14):2912-2918
Changes in the gas composition during the methane chemical vapor deposition growth of single- and double-walled carbon nanotubes over metal-supported MgO catalysts were investigated in an attempt to increase the nanotube yield. Monitoring the gas composition by gas chromatography as a function of the reaction time provides information on the activity and lifetime of the catalyst. The degree of methane decomposition, i.e., the C-H bond dissociation, was closely related to the nanotube yield, and the Fe-Mo binary catalyst exhibited a high activity. The effects of water vapor on the catalytic nanotube growth were also studied by introducing water vapor in the inlet gas. An appropriate amount of water prolonged the lifetime of the catalyst and increased the nanotube yield by 35%. 相似文献
89.
K. Nishizawa H. Kato K. Mimori T. Yoshida N. Hasegawa M. Tsuji Y. Tamaura 《Journal of Materials Science》1994,29(3):768-772
Methanation reactivity was studied for the surface carbon deposited from CO2 on the surface of Rh-bearing activated magnetite. The most active material (Rh=0.83 wt %) for methanation was prepared by the impregnation method at 60°C and showed 98% conversion at 300°C. The surface carbon was composed of elemental carbon (-carbon) and polymerized carbon (-carbon), the proportion being dependent on the density of carbon deposited. In temperature-programmed surface reaction, the extent of conversion of the - and -carbon to CH4 was 0.34 (-carbon) and 0.53 (-carbon), respectively, and the total conversion was 0.87. This result indicates that not only elemental carbon but polymerized carbon (-carbon) could be converted to CH4 on the Rh-bearing activated (-carbon) magnetite, whereas -carbon is not hydrogenated on activated magnetite. 相似文献
90.
Itaru Natori Shizue Natori Anna Kanasashi Kosuke Tsuchiya Kenji Ogino 《Reactive and Functional Polymers》2013,73(1):200-206
The synthesis of tetraphenylporphyrin (H2TPP)-end-functionalized poly(p-phenylene) (H2TPP-PPP) as a leaf-green-colored soluble semiconducting polymer with a well-controlled and defined polymer chain structure was achieved for the first time. Chloromethyl-end-functionalized poly(1,3-cyclohexadiene) (CM-PCHD) was prepared by the living anionic polymerization of 1,3-cyclohexadiene and the post-polymerization reaction of poly(1,3-cyclohexadienyl)lithium and chloro(chloromethyl)dimethylsilane. H2TPP-end-functionalized PCHD (H2TPP-PCHD) was then prepared by the addition of 5-(4-hydroxyphenyl)-10,15,20-triphenylporphyrin to CM-PCHD. The dehydrogenation of H2TPP-PCHD with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone was performed under ultrasonic irradiation, and H2TPP-PPP was obtained as a target polymer in almost quantitative yield. The –Si(CH3)2–CH2–O– bond in H2TPP-PPP effectively inhibited the coordination of the H2TPP end-group onto the PPP moiety, and the aggregation of H2TPP-PPP with the accumulation of the H2TPP end-group was formed. H2TPP-PPP exhibited a leaf-green color and had a very broad absorption band overlapping the visible-light region, similar to chlorophyll a. 相似文献