全文获取类型
收费全文 | 2803篇 |
免费 | 69篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 166篇 |
综合类 | 3篇 |
化学工业 | 611篇 |
金属工艺 | 89篇 |
机械仪表 | 31篇 |
建筑科学 | 37篇 |
能源动力 | 86篇 |
轻工业 | 202篇 |
水利工程 | 2篇 |
石油天然气 | 1篇 |
无线电 | 267篇 |
一般工业技术 | 387篇 |
冶金工业 | 776篇 |
原子能技术 | 76篇 |
自动化技术 | 143篇 |
出版年
2023年 | 15篇 |
2022年 | 26篇 |
2021年 | 56篇 |
2020年 | 24篇 |
2019年 | 20篇 |
2018年 | 32篇 |
2017年 | 43篇 |
2016年 | 57篇 |
2015年 | 23篇 |
2014年 | 63篇 |
2013年 | 110篇 |
2012年 | 76篇 |
2011年 | 108篇 |
2010年 | 69篇 |
2009年 | 103篇 |
2008年 | 100篇 |
2007年 | 82篇 |
2006年 | 76篇 |
2005年 | 84篇 |
2004年 | 63篇 |
2003年 | 65篇 |
2002年 | 67篇 |
2001年 | 48篇 |
2000年 | 43篇 |
1999年 | 73篇 |
1998年 | 314篇 |
1997年 | 207篇 |
1996年 | 133篇 |
1995年 | 68篇 |
1994年 | 73篇 |
1993年 | 85篇 |
1992年 | 42篇 |
1991年 | 38篇 |
1990年 | 31篇 |
1989年 | 31篇 |
1988年 | 24篇 |
1987年 | 23篇 |
1986年 | 19篇 |
1985年 | 28篇 |
1984年 | 17篇 |
1983年 | 20篇 |
1982年 | 20篇 |
1981年 | 18篇 |
1980年 | 16篇 |
1979年 | 14篇 |
1978年 | 18篇 |
1977年 | 20篇 |
1976年 | 37篇 |
1973年 | 8篇 |
1969年 | 10篇 |
排序方式: 共有2877条查询结果,搜索用时 156 毫秒
91.
Koizumi Hiroyasu Morio Naoki Ishikawa Alto Kondo Takumi 《Journal of Superconductivity and Novel Magnetism》2022,35(9):2357-2370
Journal of Superconductivity and Novel Magnetism - We theoretically study the superconductivity in hole-doped cuprate superconductors by employing a model composed of surface and bulk CuO $$_2$$... 相似文献
92.
Shunsuke Kato Prof. Akira Onoda Naomasa Taniguchi Prof. Ulrich Schwaneberg Prof. Takashi Hayashi 《Chembiochem : a European journal of chemical biology》2021,22(4):679-685
Directed evolution of Cp*RhIII-linked nitrobindin (NB), a biohybrid catalyst, was performed based on an in vitro screening approach. A key aspect of this effort was the establishment of a high-throughput screening (HTS) platform that involves an affinity purification step employing a starch-agarose resin for a maltose binding protein (MBP) tag. The HTS platform enables efficient preparation of the purified MBP-tagged biohybrid catalysts in a 96-well format and eliminates background influence of the host E. coli cells. Three rounds of directed evolution and screening of more than 4000 clones yielded a Cp*RhIII-linked NB(T98H/L100K/K127E) variant with a 4.9-fold enhanced activity for the cycloaddition of acetophenone oximes with alkynes. It is confirmed that this HTS platform for directed evolution provides an efficient strategy for generating highly active biohybrid catalysts incorporating a synthetic metal cofactor. 相似文献
93.
Satoshi Fujiwara Takamasa Imada Tomoya Nakagita Shinji Okada Takashi Nammoku Keiko Abe Takumi Misaka 《Food chemistry》2012,130(3):561-568
Sweet enhancing effect of neohesperidin dihydrochalcone (NHDC) or cyclamate has been reported to be synergistic in human sensory tests. However, little is known about whether these synergisms are caused by the mechanism mediated by the human sweet-taste receptor. Here, we examined the sweetness intensity of sweet tastant mixtures by measuring the responses of cultured cells stably expressing the human sweet-taste receptor. The results showed that the cell response to sucrose was synergistically potentiated by the addition of NHDC or cyclamate. Moreover, a point mutation in the transmembrane domain of hT1R3 almost completely eliminated the enhancing effects of NHDC and cyclamate. These results suggest that ligand–receptor interactions in the transmembrane domain of hT1R3 are necessary for NHDC and cyclamate to elicit the synergistic potentiation of the receptor activation. Our results may provide the foundation of a molecular basis for receptor-based synergisms of sweet tastes in mixtures of diverse sweet substances. 相似文献
94.
Samuel L. Manzello Seul-Hyun Park Sayaka SuzukiJohn R. Shields Yoshihiko Hayashi 《Fire Safety Journal》2011,46(8):568-578
Attempting to experimentally quantify the vulnerabilities of structures to ignition from firebrand showers has remained elusive. The coupling of two facilities has begun to unravel this difficult problem. The NIST Firebrand Generator (NIST Dragon) is an experimental device that can generate a firebrand shower in a safe and repeatable fashion. Since wind plays a critical role in the spread of WUI fires in the USA and urban fires in Japan, NIST has established collaboration with the Building Research Institute (BRI) in Japan. BRI maintains one of the only full scale wind tunnel facilities in the world designed specifically for fire experimentation; the Fire Research Wind Tunnel Facility (FRWTF). The present investigation is aimed at extensively quantifying firebrand penetration through building vents using full scale tests. A structure was placed inside the FRWTF and firebrand showers were directed at the structure using the NIST Dragon. The structure was fitted with a generic building vent, consisting of only a frame fitted with a metal mesh. Six different mesh sizes openings were used for testing. Behind the mesh, four different materials were placed to ascertain whether the firebrands that were able to penetrate the building mesh assembly could ignite these materials. Reduced scale test methods afford the capability to test new vent technologies and may serve as the basis for new standard testing methodologies. As a result, a new experimental facility developed at NIST is presented and is known as the NIST Dragon's LAIR (Lofting and Ignition Research). The NIST Dragon's LAIR has been developed to simulate a wind driven firebrand attack at reduced scale. The facility consists of a reduced scale Firebrand Generator (Baby Dragon) coupled to a bench scale wind tunnel. Finally, a series of full scale experiments were conducted to visualize the flow of firebrands around obstacles placed downstream of the NIST Dragon. Firebrands were observed to accumulate in front of these obstacles at a stagnation plane, as was observed when the structure was used for firebrand penetration through building vent experiments, due to flow recirculation. The accumulation of firebrands at a stagnation plane presents a severe threat to ignitable materials placed near structures. 相似文献
95.
Katsuki Hirabayashi Yoshiya Tashiro Nobuhiro Kondo Sachio Hayashi 《Journal of Applied Glycoscience》2017,64(2):33
We report production of the functional disaccharide gentiobiose β-D-Glcp-(1→6)-D-Glc by a hydrolysis reaction of hydrothermally treated Aureobasidium pullulans β-1,3-1,6-glucan as the substrate and Kitalase as the enzyme. Gentiobiose was produced over the pH range 4−6 and the concentration of gentiobiose produced decreased above pH 7. The maximum value of gentiobiose production was unaffected by the enzyme concentration. The maximum concentration of gentiobiose produced was dependent on the substrate concentration whereas the maximum ratio of gentiobiose to glucose was not. The production of gentiobiose from yeast β-1,3-1,6-glucan was lower than that from A. pullulans β-1,3-1,6-glucan. 相似文献
96.
Phase Relations and Volume Changes of Hafnia under High Pressure and High Temperature 总被引:1,自引:0,他引:1
Osamu Ohtaka Hiroshi Fukui Taichi Kunisada Tomoyuki Fujisawa Kenichi Funakoshi Wataru Utsumi Tetsuo Irifune Koji Kuroda Takumi Kikegawa 《Journal of the American Ceramic Society》2001,84(6):1369-1373
Using multi-anvil high-pressure devices and synchrotron radiation, X-ray in situ observations of HfO2 under high pressure and high temperature have been performed to investigate its phase relations and compression behavior. An orthorhombic phase (orthoI) is stable from 4 to 14.5 GPa below 1250°–1400°C and transforms to a tetragonal phase, which is one of the high-temperature forms of HfO2 , above these temperatures. Another orthorhombic phase (orthoII) with a cotunnite-type structure appears above 14.5 GPa. OrthoII is stable up to 1800°C at 21 GPa. OrthoII is quenchable to ambient conditions. The orthoI-to-orthoII transition is accompanied by ∼8 vol% decrease. The bulk moduli of orthoI and orthoII at room temperature are 220 and 312 GPa, respectively. This low compressibility of orthoII indicates that it is a potential candidate for very hard materials. 相似文献
97.
Masahiko Hayashi Kazuya Yoshimoto Naohito Hirata Kiyoshi Tanaka Nobuki Oguni Katsumasa Harada Akio Matsushita Yasuhiro Kawachi Hiroshi Sasaki 《Israel journal of chemistry》2001,41(4):241-246
Highly enantioselective addition of diketene to aldehydes was achieved by using novel Schiff base—titanium alkoxide complexes. Up to 92% ee of 5-hydroxy-3-oxoesters was obtained. This procedure provides an efficient method for the asymmetric synthesis of potential inhibitors of HMG coenzyme reductase. 相似文献
98.
Syntheses of Spinon Thermal Conductivity Materials in Sr–Cu–O System by Glass‐Ceramics Technique
下载免费PDF全文
![点击此处可从《Journal of the American Ceramic Society》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Nobuaki Terakado Yuudai Yokochi Kouki Watanabe Yoshihiro Takahashi Takumi Fujiwara 《Journal of the American Ceramic Society》2016,99(5):1565-1572
We have synthesized spinon thermal conductivity materials in Sr–Cu–O system by glass‐ceramics technique. The materials are promising for active control of thermal energy in microelectronic devices because of high and anisotropic thermal conduction, its controllability, and electric insulation. Nevertheless, research on these materials has been limited to that concerning theoretical perspectives and investigation of physical properties using large single crystals. In this study, we adopt glass‐ceramics technique to synthesize these materials: We prepared melt‐quenched multicomponent oxides including SrO and CuO, and checked its glass‐forming ability and crystallization behaviors by heating. As a result, we have found that SrCuO2 and Sr14Cu24O41, known as the spinon thermal conductivity materials, are synthesized using SrO–CuO–?Li2O–?Al2O3?–Ga2O3 system. This synthesis process for the system will provide practical application of the spinon thermal conductivity materials. 相似文献
99.
Yuta Shizukawa Shigenari Hayashi Suzue Yoneda Yasumitsu Kondo Hiroshi Tanei Shigeharu Ukai 《Oxidation of Metals》2016,86(3-4):315-326
The phase transformation behavior of a thermally grown oxide scale of FeO on pure-Fe and an Fe–2wt%Au alloy was investigated. Particular attention was paid to formation of a magnetite seam, which is the Fe3O4 layer formed at the FeO/alloy interface at an initial stage of the phase transformation, since it has important effects on the overall phase transformation of FeO scale. A thin Au(Fe) layer was found to develop on the Fe–Au alloy at the FeO/alloy interface after 32 min of oxidation at 750 °C in air. This Au(Fe) layer prevented formation of a magnetite seam and accelerated the FeO eutectoid reaction. The Au(Fe) layer acted as a “chemical diffusion barrier” for inward diffusion of Fe from the FeO to the alloy substrate across the FeO/alloy interface and prevented magnetite seam formation. 相似文献
100.
Joao Gari da Silva Fonseca Junior Takashi Oozeki Hideaki Ohtake Takumi Takashima Kazuhiko Ogimoto 《Progress in Photovoltaics: Research and Applications》2015,23(10):1203-1218
The development of methods to forecast photovoltaic (PV) power generation regionally is of utmost importance to support the spread of such power systems in current power grids. The objective of this study is to propose and to evaluate methods to forecast regional PV power 1 day ahead of time and to compare their performances. Four forecast methods were regarded, of which two are new ones proposed in this study. Together, they characterize a set of forecast methods that can be applied in different scenarios regarding availability of data and infrastructure to make the forecasts. The forecast methods were based on the use of support vector regression and weather prediction data. Evaluations were performed for 1 year of hourly forecasts using data of 273 PV systems installed in two adjacent regions in Japan, Kanto, and Chubu. The results show the importance of selecting the proper forecast method regarding the region characteristics. For Chubu, the region with a variety of weather conditions, the forecast methods based on single systems' forecasts and the one based on stratified sampling provided the best results. In this case, the best annual normalized root mean square error (RMSE) and mean absolute error (MAE) were 0.25 and 0.15 kWh/kWhavg, respectively. For Kanto, with homogeneous weather conditions, the four methods performed similarly. In this case, the lowest annual forecast errors were 0.33 kWh/kWhavg for the normalized RMSE and 0.202 kWh/kWhavg for the normalized MAE. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献