全文获取类型
收费全文 | 446篇 |
免费 | 19篇 |
专业分类
电工技术 | 18篇 |
化学工业 | 128篇 |
金属工艺 | 13篇 |
机械仪表 | 16篇 |
建筑科学 | 7篇 |
能源动力 | 20篇 |
轻工业 | 46篇 |
石油天然气 | 2篇 |
无线电 | 29篇 |
一般工业技术 | 113篇 |
冶金工业 | 16篇 |
原子能技术 | 10篇 |
自动化技术 | 47篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 3篇 |
2021年 | 8篇 |
2020年 | 5篇 |
2019年 | 5篇 |
2018年 | 8篇 |
2017年 | 6篇 |
2016年 | 20篇 |
2015年 | 4篇 |
2014年 | 25篇 |
2013年 | 28篇 |
2012年 | 19篇 |
2011年 | 25篇 |
2010年 | 22篇 |
2009年 | 20篇 |
2008年 | 20篇 |
2007年 | 26篇 |
2006年 | 15篇 |
2005年 | 23篇 |
2004年 | 25篇 |
2003年 | 10篇 |
2002年 | 10篇 |
2001年 | 7篇 |
2000年 | 8篇 |
1999年 | 8篇 |
1998年 | 10篇 |
1997年 | 10篇 |
1996年 | 6篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1993年 | 9篇 |
1992年 | 4篇 |
1991年 | 7篇 |
1990年 | 3篇 |
1989年 | 12篇 |
1988年 | 7篇 |
1987年 | 5篇 |
1986年 | 8篇 |
1985年 | 6篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 3篇 |
排序方式: 共有465条查询结果,搜索用时 15 毫秒
31.
Organometallic Bonding in an Ullmann‐Type On‐Surface Chemical Reaction Studied by High‐Resolution Atomic Force Microscopy
下载免费PDF全文
![点击此处可从《Small (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Shigeki Kawai Ali Sadeghi Toshihiro Okamoto Chikahiko Mitsui Rémy Pawlak Tobias Meier Jun Takeya Stefan Goedecker Ernst Meyer 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(38):5303-5311
The on‐surface Ullmann‐type chemical reaction synthesizes polymers by linking carbons of adjacent molecules on solid surfaces. Although an organometallic compound is recently identified as the reaction intermediate, little is known about the detailed structure of the bonded organometallic species and its influence on the molecule and the reaction. Herein atomic force microscopy at low temperature is used to study the reaction with 3,9‐diiododinaphtho[2,3‐b:2′,3′‐d]thiophene (I‐DNT‐VW), which is polymerized on Ag(111) in vacuum. Thermally sublimated I‐DNT‐VW picks up a Ag surface atom, forming a C? Ag bond at one end after removing an iodine. The C? Ag bond is usually short‐lived, and a C? Ag? C organometallic bond immediately forms with an adjacent molecule. The existence of the bonded Ag atoms strongly affects the bending angle and adsorption height of the molecular unit. Density functional theory calculations reveal the bending mechanism, which reveals that charge from the terminus of the molecule is transferred via the Ag atom into the organometallic bond and strengths the local adsorption to the substrate. Such deformations vanish when the Ag atoms are removed by annealing and C? C bonds are established. 相似文献
32.
Sylwia Nowakowska Aneliia Wäckerlin Ignacio Piquero‐Zulaica Jan Nowakowski Shigeki Kawai Christian Wäckerlin Manfred Matena Thomas Nijs Shadi Fatayer Olha Popova Aisha Ahsan S. Fatemeh Mousavi Toni Ivas Ernst Meyer Meike Stöhr J. Enrique Ortega Jonas Björk Lutz H. Gade Jorge Lobo‐Checa Thomas A. Jung 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(28):3757-3763
33.
Mitaku Shigeki; Hirokawa Takatsugu 《Protein engineering, design & selection : PEDS》1999,12(11):953-957
The average hydrophobicity of a polypeptide segment is consideredto be the most important factor in the formation of transmembranehelices, and the partitioning of the most hydrophobic (MH) segmentinto the alternative nonpolar environment, a membrane or hydrophobiccore of a globular protein may determine the type of proteinproduced. In order to elucidate the importance of the MH segmentin determining which of the two types of protein results froma given amino acid sequence, we statistically studied the characteristicsof MH helices, longer than 19 residues in length, in 97 membraneproteins whose three-dimensional structure or topology is known,as well as 397 soluble proteins selected from the Protein DataBank. The average hydrophobicity of MH helices in membrane proteinshad a characteristic relationship with the length of the protein.All MH helices in membrane proteins that were longer than 500residues had a hydrophobicity greater than 1.75 (Kyte and Doolittlescale), while the MH helices in membrane proteins smaller than100 residues could be as hydrophilic as 0.1. The possibilityof developing a method to discriminate membrane proteins fromsoluble ones, based on the effect of size on the type of proteinproduced, is discussed. 相似文献
34.
Takashi Tatsumi Shigeki Kunitomi Jun Yoshiwara Atsushi Muramatsu Hiro-o Tominaga 《Catalysis Letters》1989,3(3):223-226
In the reaction of CO-H2-NH3 on Mo/SiO2 catalysts, HCN is formed and is considered to be the principal intermediate for the formation of CH3CN. At low temperature methylamine is also formed. 相似文献
35.
36.
Shigeki Tasaka Yoshihiro Sato Nobuhito Tateyama Hisahiko Sugimoto Fumihito Fumuro Kaoru Hoshino 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1985,236(2):400-409
A new multiple scanning method is developed and applied to detect cosmic heavy nuclei. The plastic track detectors CR-39 exposed to cosmic heavy nuclei are over-etched in 8.0N NaOH for 94 h at 80°C. We found that the etched cones can easily be scanned on the plastic plates without using an optical microscope. The trajectories of heavy nuclei can be reconstructed with the naked eyes by superposing four or more over-etched plates. The charge detection threshold is obtained by this method, and appears to be 10. The charge resolution is estimated to be 1.0 charge units for iron nuclei. By adopting this method, the scanning time is much shortened and CR-39 plastic chamber size can easily be scaled up. The method is very useful for detecting particles with low flux intensity, like for searching magnetic monopoles or for measuring the high energy spectra of cosmic heavy nuclei. 相似文献
37.
38.
Cooking up an interactive olfactory game display. 总被引:2,自引:0,他引:2
Takamichi Nakamoto Shigeki Otaguro Masashi Kinoshita Masahiko Nagahama Keita Ohinishi Taro Ishida 《Computer Graphics and Applications, IEEE》2008,28(1):75-78
It's long been possible to give users outside an actual environment that environment's visual and auditory information and thus contribute to establishing presence. However, we've yet to establish much presence when users require olfactory information - such as in environments focused on foods, flowers, perfumes, or, in some cases, more offensive smells. Recently, several VR researchers have become interested in olfaction and olfactory displays that present smells in virtual environments (VEs). In this article, we describe our interactive olfactory display. One of our development goals is to confirm the assumption that users' interactions with the system increases presence. Thus, we used our interactive olfactory display to develop a cooking game in collaboration with electronic engineers and artists. 相似文献
39.
The corrosion resistivity of single-phase Au-Cu-11 at% Pd alloys was evaluated by using a parameterQ which represented the total amount of anodic reaction in a potentiostatic polarization test. The result was compared with
those for binary Au-Cu, ternary Au-Cu-11 at % Ag and some commercial alloys. The validity of usingQ as a corrosion parameter was confirmed by the good agreement between the analysed and calculated values of copper ion dissolved
into the test solution. By replacing a part of the copper in Au-Cu alloys with palladium the corrosion resistivity can be
greatly improved, but silver has no such significant effect. The value ofQ decreased by both treatments of homogenization and grain refinement of the alloy. One of the advantages of the alloy having
a single-phase structure is that inhomogeneity in the distribution of the constituents is small even in the as-cast state,
which results in a small galvanic effect. 相似文献
40.
Summary The oxidative coupling polymerization of racemic 3,3’-dihydroxy-2,2’-dimethoxy-1,1’-binaphthalene with copper(II) chloride-(-)-sparteine [(-)Sp] in methanol at room temperature was carried out and the enantiomer-selectivity during the polymerization was examined. The (R)-monomer preferentially reacted, and the purity of the unreacted monomer reached 80%ee (S) after 15 h, while that of the polymerized monomer gradually decreased from 26%ee (R) as a function of the polymerization. The ratio of the rate constants of both enantiomers, s=kR/kS, was determined to be 2.3. The model coupling reaction of the mono-benzylated (R)-monomer with CuCl2-(-)Sp showed that the R-configuration with respect to the carbon-carbon bonds between the monomer units was selectively constructed during the polymerization. 相似文献