全文获取类型
收费全文 | 1969篇 |
免费 | 143篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 14篇 |
化学工业 | 502篇 |
金属工艺 | 62篇 |
机械仪表 | 68篇 |
建筑科学 | 90篇 |
矿业工程 | 7篇 |
能源动力 | 175篇 |
轻工业 | 353篇 |
水利工程 | 7篇 |
石油天然气 | 16篇 |
无线电 | 71篇 |
一般工业技术 | 389篇 |
冶金工业 | 41篇 |
原子能技术 | 10篇 |
自动化技术 | 308篇 |
出版年
2024年 | 9篇 |
2023年 | 23篇 |
2022年 | 48篇 |
2021年 | 82篇 |
2020年 | 69篇 |
2019年 | 61篇 |
2018年 | 125篇 |
2017年 | 106篇 |
2016年 | 116篇 |
2015年 | 81篇 |
2014年 | 119篇 |
2013年 | 301篇 |
2012年 | 94篇 |
2011年 | 122篇 |
2010年 | 150篇 |
2009年 | 117篇 |
2008年 | 100篇 |
2007年 | 97篇 |
2006年 | 44篇 |
2005年 | 28篇 |
2004年 | 31篇 |
2003年 | 14篇 |
2002年 | 23篇 |
2001年 | 9篇 |
2000年 | 11篇 |
1999年 | 9篇 |
1998年 | 10篇 |
1997年 | 5篇 |
1996年 | 9篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 11篇 |
1984年 | 9篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1981年 | 13篇 |
1980年 | 6篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 5篇 |
1975年 | 2篇 |
1974年 | 4篇 |
1973年 | 3篇 |
1971年 | 1篇 |
排序方式: 共有2113条查询结果,搜索用时 31 毫秒
1.
2.
Wireless Networks - Nowadays, Wireless Sensor Networks are one of the fundamental infrastructures for IoT technology. Although WSN has been researched for a decade, providing energy efficiency for... 相似文献
3.
Polyester particles in concrete are preferred because they provide thermal, chemical and water resistance. In this study, thermal conductivity, electrical resistivity, mechanical strength and water resistance properties of concretes containing polyester granules such as flame-retardant polyester, cationic dyeable polyester and polyester with a low melting point-filled concrete have been analyzed using a full factorial design via Minitab® version 17. The effect of the most influential factors on thermal conductivity of polyester aggregate reinforced concrete composite has been determined as an interaction between the cationic dyeable and low-melt–point polyester. This mixture is suitable for production of thermal insulating concrete. Moreover, it is concluded that cationic dyeable polyester is the highest corrosion- and water-resistant product among the polyesters used in this study. The recovery rate of 33.94% in the thermal conductivity and 214.89% in the electrical resistivity of polyester-reinforced concrete composites has been obtained with a 28-day compressive strength loss of 41.94% according to the reference concrete in the full factorial design application. These results indicate that the polyester-reinforced concrete composites are quite effective in achieving thermal and corrosion resistance concrete but with noticeable compressive strength loss. 相似文献
4.
5.
6.
7.
Ayşegül Güven 《中国工程学刊》2019,42(4):357-365
Diagnostic efforts to identify alcoholism are frequently subjective; however, recent technological advances have allowed the automated assessment of objective signals. To improve the performance of the automated classification of patients with alcohol dependence (AD) and controls, we analyzed features of event-related potentials (ERPs) in 72 subjects with AD and 42 controls while the subjects underwent three different visual oddball tasks. In addition to such commonly used morphological features (MFs) as time-domain amplitude and latency components as well as discrete wavelet transform coefficient entropies (WEs), we analyzed Hu moment invariants (HMIs) in this study. Smaller P3 and P2 amplitudes, longer latencies, lower WE values, and lower HMI values were observed for AD subjects relative to those observed for controls. We used a Naïve Bayes algorithm to compare classification accuracies among MFs, WEs, HMIs, combinations of MFs/WEs, and combinations of all three characteristics. We found that HMIs improved the classification accuracy by 17%. Our findings demonstrated that a combined feature analysis of ERPs obtained during a visual oddball task can be a useful and discriminative tool for diagnostic purposes in alcoholism and that HMIs show promise for improving the objective diagnosis of alcoholism and similar diseases. 相似文献
8.
The breath figure (BF) method is an effective process for fabricating porous polymeric films. In this study, we fabricated porous polymer films from thermoplastic polyurethane (PU) through static BF with CHCl3 as a solvent under 55–80% relative humidity. The porous PU films were prepared within various pore structures and sizes, which were adjustable, depending on the fabrication conditions. The humidity and exposure time were examined as variable parameters affecting the surface morphology, wettability, and cytotoxicity. Atorvastatin calcium, a hyperlipidemic agent, was loaded into the porous films during the casting process, and the drug-loading and drug-releasing behaviors of the porous PU membranes were evaluated. Approximately 60–80% of the drug was released in 14 days. The films exhibited sustained drug-release performances because of the hydrophobicity and nonbiodegradable nature of PU for perivascular drug administration. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47658. 相似文献
9.
Altındal Yerişkin Seçkin Şafak Asar Yasemin 《Journal of Materials Science: Materials in Electronics》2021,32(18):22860-22867
Journal of Materials Science: Materials in Electronics - To determine which of graphene (Gr) doping ratio (pure, 3–5%) into PVA is better or not, Gr-based PVA organic thin film were grown... 相似文献
10.