全文获取类型
收费全文 | 1786篇 |
免费 | 70篇 |
国内免费 | 8篇 |
专业分类
电工技术 | 110篇 |
综合类 | 6篇 |
化学工业 | 639篇 |
金属工艺 | 70篇 |
机械仪表 | 51篇 |
建筑科学 | 48篇 |
能源动力 | 115篇 |
轻工业 | 162篇 |
水利工程 | 1篇 |
石油天然气 | 2篇 |
无线电 | 93篇 |
一般工业技术 | 331篇 |
冶金工业 | 18篇 |
原子能技术 | 52篇 |
自动化技术 | 166篇 |
出版年
2024年 | 2篇 |
2023年 | 18篇 |
2022年 | 41篇 |
2021年 | 70篇 |
2020年 | 30篇 |
2019年 | 21篇 |
2018年 | 34篇 |
2017年 | 40篇 |
2016年 | 56篇 |
2015年 | 32篇 |
2014年 | 63篇 |
2013年 | 143篇 |
2012年 | 91篇 |
2011年 | 132篇 |
2010年 | 99篇 |
2009年 | 134篇 |
2008年 | 108篇 |
2007年 | 92篇 |
2006年 | 73篇 |
2005年 | 84篇 |
2004年 | 68篇 |
2003年 | 63篇 |
2002年 | 50篇 |
2001年 | 23篇 |
2000年 | 32篇 |
1999年 | 34篇 |
1998年 | 26篇 |
1997年 | 21篇 |
1996年 | 26篇 |
1995年 | 21篇 |
1994年 | 20篇 |
1993年 | 22篇 |
1992年 | 6篇 |
1991年 | 7篇 |
1990年 | 8篇 |
1989年 | 10篇 |
1988年 | 10篇 |
1987年 | 3篇 |
1986年 | 8篇 |
1985年 | 4篇 |
1984年 | 8篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1977年 | 3篇 |
1975年 | 2篇 |
1973年 | 4篇 |
1972年 | 2篇 |
1970年 | 1篇 |
排序方式: 共有1864条查询结果,搜索用时 15 毫秒
41.
Shoki Tashiro Atsushi Tatsuma Masaki Aono 《Multimedia Tools and Applications》2017,76(21):22059-22076
We have witnessed 3D shape models abundant in many application fields including 3D CAD/CAM, augmented/mixed reality (AR/MR), and entertainment. Creating 3D shape models from scratch is still very expensive. Efficient and accurate methods for shape retrieval is essential for 3D shape models to be reused. To retrieve similar 3D shape models, one must provide an arbitrary 3D shape as a query. Most of the research on 3D shape retrieval has been conducted with a “whole” shape as a query (aka whole-to-whole shape retrieval), while a “part” shape (aka part-to-whole shape retrieval) is more practically requested as a query especially by mechanical engineering with 3D CAD/CAM applications. A “part” shape is naturally constructed by a 3D range scanner as an input device. In this paper, we focus on the efficient method for part-to-whole shape retrieval where the “part” shape is assumed to be given by a 3D range scanner. Specifically, we propose a Super-Vector coding feature with SURF local features extracted from the View-Normal-Angle image, or the image synthesized by taking account of the angle between the view vector and the surface normal vector, together with the depth-buffered image, for part-to-whole shape retrieval. In addition, we propose a weighted whole-to-whole re-ranking method taking advantage of global information based on the result of part-to-whole shape retrieval. Through experiments we demonstrate that our proposed method outperforms the previous methods with or without re-ranking. 相似文献
42.
Michio Tajima Masatoshi Ikebe Yoshio Ohshita Atsushi Ogura 《Journal of Electronic Materials》2010,39(6):747-750
We investigated the effect of Fe contamination on the electronic properties of dislocation clusters in relation to oxygen
precipitation in multicrystalline silicon (mc-Si). Photoluminescence (PL) spectroscopy and mapping were performed at room
and liquid-He temperatures on mc-Si wafers before and after Fe contamination. PL spectra consisted of the band-edge emission,
the 0.78-eV emission associated with oxygen precipitates, and the dislocation-related D-lines. The Fe contamination increased
the electrically active dislocation clusters. Part of these clusters acted as preferential oxygen precipitation sites, and
their electronic properties were not further influenced by the Fe contamination. 相似文献
43.
The tensile strengths and elongations of starch films prepared from various unmodified and modified starches were measured. These properties were improved by addition of urea and polyvinyl alcohol to the starch paste. The results obtained were as follows.
- 1 The heating temperature greatly affected the tensile strength and elongation of various unmodified starches. Potato starch gave the best film.
- 2 Introduction of hydroxyethyl groups into corn starch had unexpectedly little affect on the properties of the films.
- 3 A combination of hydroxyethylation and acid-modification slightly improved the properties of the films.
- 4 No film could be obtained after combinations of hydroxyethylation and hypochlorite-oxidation, pyrodextrinization or α-amylase-dextrinization. However, addition of urea to these modified starches resulted in good films.
- 5 On addition of urea the elongation of starch films increased and the pastes adhered uniformly to water repellent surfaces.
- 6 A film with the best properties was prepared from a mixture of 67% acid-modified hydroxyethyl starch, 13% urea and 20% polyvinyl alcohol.
44.
Atsushi Nakanishi Takashi Yasuda Kazuki Horita Hironori Takahashi 《Journal of Infrared, Millimeter and Terahertz Waves》2018,39(1):36-44
We measured the thermal dependencies of the refractive index and the absorption coefficient of high-resistivity silicon. We found that the refractive index varied slightly with temperature, and the absorption coefficient was very low and remained approximately constant as the temperature was changed. As a result, the conditions for terahertz propagation in silicon could be controlled by changing the refractive index without any absorption loss. As one application of this effect, we developed a terahertz time delay generator that can generate a terahertz time delay by changing the temperature of the medium through which the terahertz beam passes, without the need for any mechanical delay. We demonstrated generation of a terahertz time delay of approximately 6.6 ps. 相似文献
45.
Yuta Uenoyama Atsushi Matsuda Kazune Ohashi Koji Ueda Misaki Yokoyama Takuya Kyoutou Kouji Kishi Youichi Takahama Masaaki Nagai Takaaki Ohbayashi Osamu Hotta Hideki Matsuzaki 《International journal of molecular sciences》2022,23(9)
Aberrant glycosylation of IgA1 is involved in the development of IgA nephropathy (IgAN). There are many reports of IgAN markers focusing on the glycoform of IgA1. None have been clinically applied as a routine test. In this study, we established an automated sandwich immunoassay system for detecting aberrant glycosylated IgA1, using Wisteria floribunda agglutinin (WFA) and anti-IgA1 monoclonal antibody. The diagnostic performance as an IgAN marker was evaluated. The usefulness of WFA for immunoassays was investigated by lectin microarray. A reliable standard for quantitative immunoassay measurements was designed by modifying a purified IgA1 substrate. A validation study using multiple serum specimens was performed using the established WFA-antibody sandwich automated immunoassay. Lectin microarray results showed that WFA specifically recognized N-glycans of agglutinated IgA1 in IgAN patients. The constructed IgA1 standard exhibited a wide dynamic range and high reactivity. In the validation study, serum WFA-reactive IgA1 (WFA+-IgA1) differed significantly between healthy control subjects and IgAN patients. The findings indicate that WFA is a suitable lectin that specifically targets abnormal agglutinated IgA1 in serum. We also describe an automated immunoassay system for detecting WFA+-IgA1, focusing on N-glycans. 相似文献
46.
Riku Kawasaki Kosuke Kondo Risako Miura Keita Yamana Hinata Isozaki Risako Shimada Shogo Kawamura Hidetoshi Hirano Tomoki Nishimura Naoki Tarutani Kiyofumi Katagiri Alexandra Stubelius Shin-ichi Sawada Yoshihiro Sasaki Kazunari Akiyoshi Atsushi Ikeda 《International journal of molecular sciences》2022,23(9)
Developing photoactivatable theranostic platforms with integrated functionalities of biocompatibility, targeting, imaging contrast, and therapy is a promising approach for cancer diagnosis and therapy. Here, we report a theranostic agent based on a hybrid nanoparticle comprising fullerene nanocrystals and gold nanoparticles (FGNPs) for photoacoustic imaging and photothermal therapy. Compared to gold nanoparticles and fullerene crystals, FGNPs exhibited stronger photoacoustic signals and photothermal heating characteristics by irradiating light with an optimal wavelength. Our studies demonstrated that FGNPs could kill cancer cells due to their photothermal heating characteristics in vitro. Moreover, FGNPs that are accumulated in tumor tissue via the enhanced permeation and retention effect can visualize tumor tissue due to their photoacoustic signal in tumor xenograft model mice. The theranostic agent with FGNPs shows promise for cancer therapy. 相似文献
47.
A Method for Reducing the Dead‐Time Voltage and Impedance Voltage in a Series Voltage Compensator 下载免费PDF全文
Atsushi Nakata Masahiro Nozaki Akihiro Torii Akiteru Ueda 《Electrical Engineering in Japan》2014,186(3):85-93
Many research groups are developing series voltage compensators. In a series converter, since a transformer is used in series in the power system, the power system current flows into the voltage source inverter through the transformer. The inverter current, which is determined by the transformation ratio, gives rise to an error voltage that consists of a dead‐time voltage and an impedance voltage. The error voltage is generated even when the reference voltage is zero. This paper describes the mechanism by which the error voltage occurs and proposes a method for reducing the error voltage. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 186(3): 85–93, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22333 相似文献
48.
Mechanically Robust and Self‐Healable Superlattice Nanocomposites by Self‐Assembly of Single‐Component “Sticky” Polymer‐Grafted Nanoparticles 下载免费PDF全文
49.
General topology optimization method with continuous and discrete orientation design using isoparametric projection 下载免费PDF全文
Tsuyoshi Nomura Ercan M. Dede Jaewook Lee Shintaro Yamasaki Tadayoshi Matsumori Atsushi Kawamoto Noboru Kikuchi 《International journal for numerical methods in engineering》2015,101(8):571-605
A general topology optimization method, which is capable of simultaneous design of density and orientation of anisotropic material, is proposed by introducing orientation design variables in addition to the density design variable. In this work, the Cartesian components of the orientation vector are utilized as the orientation design variables. The proposed method supports continuous orientation design, which is out of the scope of discrete material optimization approaches, as well as design using discrete angle sets. The advantage of this approach is that vector element representation is less likely to fail into local optima because it depends less on designs of former steps, especially compared with using the angle as a design variable (Continuous Fiber Angle Optimization) by providing a flexible path from one angle to another with relaxation of orientation design space. An additional advantage is that it is compatible with various projection or filtering methods such as sensitivity filters and density filters because it is free from unphysical bound or discontinuity such as the one at θ = 2π and θ = 0 seen with direct angle representation. One complication of Cartesian component representation is the point‐wise quadratic bound of the design variables; that is, each pair of element values has to reside in a given circular bound. To overcome this issue, we propose an isoparametric projection method, which transforms box bounds into circular bounds by a coordinate transformation with isoparametric shape functions without having the singular point that is seen at the origin with polar coordinate representation. A new topology optimization method is built by taking advantage of the aforementioned features and modern topology optimization techniques. Several numerical examples are provided to demonstrate its capability. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
50.
Yuji Higaki Ryosuke Okazaki Tatsuya Ishikawa Moriya Kikuchi Noboru Ohta Atsushi Takahara 《Polymer》2014
The chain stiffness and local chain conformation of atactic poly(α-methylene-γ-butyrolactone) (PMBL), which is a side chain cyclic structural analog of poly(methyl methacrylate) (PMMA), with a weight-average molecular weight (Mw) ranging from 2.8 × 103 to 2.6 × 106 in N,N-dimethylformamide (DMF) and γ-butyrolactone (GBL) were characterized by size exclusion chromatography with a multi-angle light-scattering detector (SEC-MALS) and synchrotron radiation small-angle X-ray scattering (SAXS). Based on the Kratky-Porod worm-like chain model, the scattering functions and the Mw dependence of z-average root-mean-square radius of gyration <S2>z1/2 yielded the Kuhn segment lengths λ−1, the diameter of the PMBL chains d, and the excluded-volume strengths in DMF and GBL. The local conformation of atactic PMBL in DMF and GBL were slightly larger than those of atactic PMMA, due to the presence of the conformationally rigid lactone ring structure. 相似文献