全文获取类型
收费全文 | 1190篇 |
免费 | 58篇 |
国内免费 | 12篇 |
专业分类
电工技术 | 23篇 |
综合类 | 2篇 |
化学工业 | 214篇 |
金属工艺 | 28篇 |
机械仪表 | 32篇 |
建筑科学 | 52篇 |
能源动力 | 63篇 |
轻工业 | 98篇 |
水利工程 | 14篇 |
石油天然气 | 27篇 |
无线电 | 201篇 |
一般工业技术 | 214篇 |
冶金工业 | 101篇 |
原子能技术 | 10篇 |
自动化技术 | 181篇 |
出版年
2024年 | 4篇 |
2023年 | 20篇 |
2022年 | 47篇 |
2021年 | 82篇 |
2020年 | 56篇 |
2019年 | 43篇 |
2018年 | 66篇 |
2017年 | 46篇 |
2016年 | 52篇 |
2015年 | 25篇 |
2014年 | 44篇 |
2013年 | 91篇 |
2012年 | 50篇 |
2011年 | 63篇 |
2010年 | 42篇 |
2009年 | 54篇 |
2008年 | 47篇 |
2007年 | 42篇 |
2006年 | 29篇 |
2005年 | 18篇 |
2004年 | 16篇 |
2003年 | 20篇 |
2002年 | 20篇 |
2001年 | 11篇 |
2000年 | 6篇 |
1999年 | 15篇 |
1998年 | 30篇 |
1997年 | 21篇 |
1996年 | 18篇 |
1995年 | 14篇 |
1994年 | 13篇 |
1993年 | 16篇 |
1992年 | 16篇 |
1991年 | 11篇 |
1990年 | 16篇 |
1989年 | 10篇 |
1988年 | 8篇 |
1987年 | 11篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 8篇 |
1983年 | 5篇 |
1982年 | 7篇 |
1981年 | 3篇 |
1980年 | 6篇 |
1977年 | 4篇 |
1976年 | 5篇 |
1975年 | 4篇 |
1973年 | 2篇 |
1972年 | 3篇 |
排序方式: 共有1260条查询结果,搜索用时 15 毫秒
41.
42.
43.
Mohammed Saleh Zeynep Bilici Merve Kaya Mutlu Yalvac Hudaverdi Arslan H. Cengiz Yatmaz Nadir Dizge 《Advanced Powder Technology》2021,32(4):1264-1275
The use of naturally present heterogeneous catalysts has recently been an essential issue in the Fenton and photo-Fenton processes. In this study, the uses of basalt as a catalyst for the Fenton and photo-Fenton reactions for methylene Blue (MB) and Basic Red 18 (BR18) degradations were investigated. Basalt was selected because of the presence of the iron (III) oxide in the structure. Basalt was characterized by X-Ray Fluorescence (XRF) and X-Ray Diffraction (XRD) analysis to obtain the chemical composition and the crystalline phase. The surface charge and the surface area were obtained by zeta potential and Brunauer Emmett-Teller (BET) analysis. Fourier Transform Infrared Spectroscopy (FTIR) and scanning electron microscope (SEM) were utilized to explore the functional group and the surface morphology. Fenton and photo-Fenton processes were applied to explore the best degradation method. Adsorption was also tested and the adsorption process had minimum removal efficiency (12% for MB and 17% for BR18). The removal efficiencies for MB and BR18 by the Fenton process were 87% and 28%, respectively. The photo-Fenton process had maximum removal efficiency with 100% for MB and 70% for BR18. The optimum conditions were 70 mg/L dye concentration, 5 mM H2O2, 1.0 g/L basalt loading and pH 2. Basalt has shown reuse capability as a catalyst for three consecutive cycles. 相似文献
44.
With the rapid development in business transactions, especially in recent years, it has become necessary to develop different mechanisms to trace business user records in web server log in an efficient way. Online business transactions have increased, especially when the user or customer cannot obtain the required service. For example, with the spread of the epidemic Coronavirus (COVID-19) throughout the world, there is a dire need to rely more on online business processes. In order to improve the efficiency and performance of E-business structure, a web server log must be well utilized to have the ability to trace and record infinite user transactions. This paper proposes an event stream mechanism based on formula patterns to enhance business processes and record all user activities in a structured log file. Each user activity is recorded with a set of tracing parameters that can predict the behavior of the user in business operations. The experimental results are conducted by applying clustering-based classification algorithms on two different datasets; namely, Online Shoppers Purchasing Intention and Instacart Market Basket Analysis. The clustering process is used to group related objects into the same cluster, then the classification process measures the predicted classes of clustered objects. The experimental results record provable accuracy in predicting user preferences on both datasets. 相似文献
45.
Alenazy Wael Mohammad Alqahtani Abdullah Saleh 《Multimedia Tools and Applications》2021,80(5):7411-7431
Multimedia Tools and Applications - Face detection by low-resolution image (LR) is one of the key aspects of Human-Computer Interaction(HCI). Due to the LR image, which has changes in pose,... 相似文献
46.
Wireless Networks - Cellular vehicle-to-everything (C-V2X) communications have elicited significant scrutiny in recent years owing to amenities such as comfort, efficiency, and an enhanced... 相似文献
47.
Mónica B. Betancor Ma. José Caballero Genciana Terova Samuela Corà Reda Saleh Tibiábin Benítez-Santana J. Gordon Bell Carmen María Hernández-Cruz Marisol Izquierdo 《Lipids》2012,47(12):1193-1207
Docosahexaenoic acid (DHA) is an essential fatty acid necessary for many biochemical, cellular and physiological functions in fish. However, high dietary levels of DHA increase free radical injury in sea bass (Dicentrarchus labrax) larvae muscle, even when vitamin E (α-tocopherol, α-TOH) is increased. Therefore, the inclusion of other nutrients with complementary antioxidant functions, such as vitamin C (ascorbic acid, vitC), could further contribute to prevent these lesions. The objective of the present study was to determine the effect of vitC inclusion (3,600?mg/kg) in high DHA (5?% DW) and α-TOH (3,000?mg/kg) microdiets (diets 5/3,000 and 5/3,000?+?vitC) in comparison to a control diet (1?% DHA DW and 1,500?mg/kg of α-TOH; diet 1/1,500) on sea bass larvae growth, survival, whole body biochemical composition and thiobarbituric acid reactive substances (TBARS) content, muscle morphology, skeletal deformities and antioxidant enzymes, insulin-like growth factors (IGFs) and myosin expression (MyHC). Larvae fed diet 1/1,500 showed the best performance in terms of total length, incidence of muscular lesions and ossification degree. IGFs gene expression was elevated in 5/3,000 diet larvae, suggesting an increased muscle mitogenesis that was confirmed by the increase in the mRNA copies of MyHC. vitC effectively controlled oxidative damages in muscle, increased α-TOH larval contents and reduced TBARS content and the occurrence of skull deformities. The results of the present study showed the antioxidant synergism between vitamins E and C when high contents of DHA are included in sea bass larvae diets. 相似文献
48.
49.
Verônica M. F. Frade Attilio Converti Saleh Al Arni Milena F. Silva Mauri S. A. Palma 《化学工程与技术》2017,40(4):663-669
Enrofloxacin is a synthetic second‐generation fluoroquinolone used as an antimicrobial agent exclusively in veterinary medicine. To simulate the treatment of wastewater contaminated by enrofloxacin, four‐day long fed‐batch runs were carried out according to the Fenton process with an enrofloxacin solution as model, to which hydrogen peroxide and ferrous ion were added twice a day. The residual enrofloxacin concentration was practically coincident to that detected at the end of the batch tests. Hydrogen peroxide was almost completely consumed after each feeding period, while the total organic carbon (TOC) concentration decreased gradually within three days, corresponding to a reduction > 58 %. From the third day on, the TOC falling rate was quite low. A yellow sludge settled due to the precipitation of both Fe(OH)3 and a complex formed by ferric ion with adsorbed enrofloxacin and/or its oxidation products. 相似文献
50.