全文获取类型
收费全文 | 1822篇 |
免费 | 87篇 |
国内免费 | 10篇 |
专业分类
电工技术 | 25篇 |
综合类 | 2篇 |
化学工业 | 378篇 |
金属工艺 | 51篇 |
机械仪表 | 44篇 |
建筑科学 | 82篇 |
矿业工程 | 18篇 |
能源动力 | 63篇 |
轻工业 | 203篇 |
水利工程 | 16篇 |
石油天然气 | 19篇 |
无线电 | 183篇 |
一般工业技术 | 277篇 |
冶金工业 | 203篇 |
原子能技术 | 23篇 |
自动化技术 | 332篇 |
出版年
2023年 | 37篇 |
2022年 | 39篇 |
2021年 | 47篇 |
2020年 | 33篇 |
2019年 | 40篇 |
2018年 | 53篇 |
2017年 | 47篇 |
2016年 | 60篇 |
2015年 | 39篇 |
2014年 | 48篇 |
2013年 | 134篇 |
2012年 | 82篇 |
2011年 | 111篇 |
2010年 | 73篇 |
2009年 | 88篇 |
2008年 | 103篇 |
2007年 | 79篇 |
2006年 | 81篇 |
2005年 | 67篇 |
2004年 | 49篇 |
2003年 | 37篇 |
2002年 | 38篇 |
2001年 | 35篇 |
2000年 | 28篇 |
1999年 | 31篇 |
1998年 | 41篇 |
1997年 | 25篇 |
1996年 | 16篇 |
1995年 | 17篇 |
1994年 | 15篇 |
1993年 | 25篇 |
1992年 | 18篇 |
1991年 | 9篇 |
1990年 | 15篇 |
1989年 | 19篇 |
1988年 | 14篇 |
1987年 | 11篇 |
1986年 | 11篇 |
1985年 | 17篇 |
1984年 | 18篇 |
1983年 | 13篇 |
1982年 | 19篇 |
1981年 | 16篇 |
1980年 | 11篇 |
1979年 | 18篇 |
1977年 | 7篇 |
1976年 | 9篇 |
1975年 | 9篇 |
1974年 | 10篇 |
1973年 | 10篇 |
排序方式: 共有1919条查询结果,搜索用时 15 毫秒
71.
Cecil D. Elliott 《Journal of Architectural Education》2013,67(3):35-37
It is a truism that the essential qualities of a work of architecture cannot, since architecture is a visual art, be fully conveyed in words. No one would seriously maintain that this absolves those whose business it is to write or talk about architecture from the obligation to use words with some regard for exactness. Yet all too often we behave as if it did; certain words are bandied about as if all were agreed as to what they meant at any time, whereas in fact they may mean different things at different times, and even different things to different people at one time. Cecil Elliott here takes up the case of one such word, a small but much-abused one, isolating four distinct phenomena which it can denote in an architectural context and pursuing his inquiry beyond the realm of semantics to consider their practical implications for the designer. 相似文献
72.
73.
74.
Matthew L. Breeze Elisa Leyva‐Guerrero Grant R. Yeaman Yelena Dudin Ryan Akel Phil Brune Fred Claussen Cecil Dharmasri Jenny Golbach Rong Guo Carl Maxwell Laura Privalle Hilary Rogers Kai Liu Guomin Shan Michele Yarnall Denise Thiede Nancy Gillikin 《Journal of the American Oil Chemists' Society》2015,92(8):1085-1092
Soybean agglutinin (SBA) protein, also known as soybean lectin, is regarded as an anti‐nutrient due to its negative effect on the ability of monogastric animals to gain weight following consumption of raw soybean seed. Historically, SBA has been measured using a time‐consuming and cumbersome hemagglutination procedure. The objective of our research was to obtain a validated methodology that is precise and accurate in the measurement of SBA while allowing minimally equipped laboratories to effectively conduct the analysis, thus our focus was on evaluating an existing commercially available ELISA, an enzyme‐linked‐lectin‐assay (ELLA), and a hybrid ELISA/ELLA. A new ELLA technique that can detect and quantify lectins was chosen and modified specifically for the quantitation of SBA in soybean seed. The proposed ELLA methodology is similar to a standard sandwich ELISA, and uses polyacrylamide‐linked N‐acetylgalactosamine (Gal–NAc–PAA) for a capture phase and the biotinylated version (Gal–NAc–PAA–Biotin) for detection. Based upon the validation data, the ELLA method can precisely and accurately determine soybean lectin levels in soybean seed. The validated ELLA method was used to quantify SBA in nine commercial soybean varieties introduced between 1972 and 2008 and demonstrated that the natural variability of SBA is subject to the effects of genotype and environment. 相似文献
75.
A novel magnetic nano-sorbent was synthesized by Schiff’s base formation via covalent bonding of gelatin to the surface of nano-magnetite-immobilized-3-aminopropyltrimethoxysilane (Nano-Fe3O4-Si-N=Gelatin). The structure was confirmed by the FT-IR, TGA, and SEM. The maximum capacity of Cd(II) and Pb(II) were identified as 440 and 400 µmol g?1, respectively. The separation characteristics were evaluated in presence of various controlling factors. The sorption processes of Cd(II) and Pb(II) were found to follow the postulates of Langmuir, Brunauer-Emmer-Teller, and Dubinin Radushkevich isotherm models. The potential applications of Nano-Fe3O4-Si-N=Gelatin in water treatment of Cd(II) and Pb(II) were successfully accomplished using a micro-column technique. 相似文献
76.
77.
Fabrication of high aspect ratio and open‐ended TiO2 nanotube photocatalytic arrays through electrochemical anodization
下载免费PDF全文
![点击此处可从《American Institute of Chemical Engineers》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Roong Jien Wong Sanly Liu Yun Hau Ng Rose Amal 《American Institute of Chemical Engineers》2016,62(2):415-420
Well‐aligned, high aspect‐ratio and open‐ended TiO2 nanotube arrays secured within a Ti foil (TiO2 nanotubes cartridge) were successfully prepared through the double‐sided anodization method. With ~210 µm of nanotube length, the anodic growth of TiO2 was accelerated and stabilized by the lactic acid‐containing ethylene glycol electrolyte. In the absence of lactic acid, the anodization led to detachment of nanotubes from the Ti foil after 5–6 h of high voltage (80 V) anodization. Transmission electron microscope image and Raman spectrum revealed that the as‐anodized TiO2 nanotube arrays without annealing treatment were partially crystalline anatase and demonstrated photocatalytic activity in the mineralization of formic acid. © 2015 American Institute of Chemical Engineers AIChE J, 62: 415–420, 2016 相似文献
78.
Mokhtar Adel Boukoussa Bouhadjar Baba Ahmed Abderrazzak Abdelkrim Soumia Djelad Amal Hachemaoui Mohammed Zaoui Farouk Bengueddach Abdelkader Sassi Mohamed 《Journal of Inorganic and Organometallic Polymers and Materials》2022,32(7):2615-2633
Journal of Inorganic and Organometallic Polymers and Materials - The discharge of industrial waste comprising organic pollutants into aquatic environment induces numerous health risks. Crosslinked... 相似文献
79.
Joanna Dawczyk Ecaterina Ware Mahmoud Ardakani Joe Russo Hugh Spikes 《Tribology Letters》2018,66(4):155
Focussed ion beam milling (FIB) followed by TEM has been used to study ZDDP tribofilms on rubbed steel surfaces. It has been found that the impact of high energy platinum and gallium ions during FIB causes significant morphological and structural changes to the uppermost 30–50 nm of a ZDDP tribofilm. This can be prevented by the low energy deposition of a quite thick gold layer prior to installation of the sample in the FIB facility. This problem, and its solution, have been quite widely reported in the non-tribology literature but have not previously been highlighted in the application of FIB to study tribological surfaces. It has also been found, using this gold pre-deposition method, that the bulk of the ZDDP tribofilm studied has a polycrystalline structure. 相似文献
80.
Toward multiple maximum power point estimation of photovoltaic systems based on semiconductor theory
Jen‐Cheng Wang Yu‐Li Su Kun‐Chang Kuo Jyh‐Cherng Shieh Joe‐Air Jiang 《Progress in Photovoltaics: Research and Applications》2015,23(7):847-861
Environmental conditions, such as temperature, non‐uniform irradiation, and solar shading, deeply affect the characteristics of photovoltaic (PV) modules in PV‐assisted generation systems. Several local maximum power points (MPPs) are found in the power–voltage curve of PV systems constructed by series/parallel‐connected PV modules under partially shaded conditions. The characteristics of PV systems change unpredictably when multiple MPPs occur, so the actual MPP tracking (MPPT) becomes a difficult task. Conventional MPPT methods for the PV systems under partially shaded conditions cannot quickly find the actual MPP such that the optimal utilization of PV systems cannot be achieved. Based on the p–n junction semiconductor theory, we develop a multipoint direct‐estimation (MPDE) method to directly estimate the multiple MPPs of the PV systems under partially shaded conditions and to cope with the mentioned difficulties. Using the proposed MPDE method, the multiple MPPs of the PV systems under partially shaded conditions can be directly determined from their irradiated current–voltage and power–voltage characteristic curves. The performances of the proposed MPDE method are evaluated by examining the characteristics of multiple MPPs of PV systems with respect to different shading strengths and numbers of the shaded PV modules and also tested using the field data. The experimental results demonstrate that the proposed MPDE method can simply and accurately estimate the multiple MPPs of the PV systems under partially shaded conditions. The optimization of MPP control models and the MPPT for PV systems could be achieved promisingly by applying the proposed method. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献