全文获取类型
收费全文 | 1513篇 |
免费 | 111篇 |
国内免费 | 18篇 |
专业分类
电工技术 | 23篇 |
综合类 | 5篇 |
化学工业 | 382篇 |
金属工艺 | 45篇 |
机械仪表 | 43篇 |
建筑科学 | 56篇 |
矿业工程 | 2篇 |
能源动力 | 89篇 |
轻工业 | 137篇 |
水利工程 | 34篇 |
石油天然气 | 14篇 |
无线电 | 134篇 |
一般工业技术 | 336篇 |
冶金工业 | 80篇 |
原子能技术 | 44篇 |
自动化技术 | 218篇 |
出版年
2024年 | 6篇 |
2023年 | 21篇 |
2022年 | 67篇 |
2021年 | 110篇 |
2020年 | 89篇 |
2019年 | 104篇 |
2018年 | 101篇 |
2017年 | 104篇 |
2016年 | 117篇 |
2015年 | 55篇 |
2014年 | 83篇 |
2013年 | 126篇 |
2012年 | 92篇 |
2011年 | 118篇 |
2010年 | 76篇 |
2009年 | 54篇 |
2008年 | 52篇 |
2007年 | 42篇 |
2006年 | 19篇 |
2005年 | 14篇 |
2004年 | 7篇 |
2003年 | 10篇 |
2002年 | 13篇 |
2001年 | 8篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 29篇 |
1997年 | 10篇 |
1996年 | 15篇 |
1995年 | 9篇 |
1994年 | 5篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 7篇 |
1988年 | 11篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1979年 | 6篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有1642条查询结果,搜索用时 19 毫秒
991.
Majid Azarang Arezo Bakhtiyari Reza Rakhshani Abdol Mahmood Davarpanah Mousa Aliahmad Maryam Farifteh Jahantigh 《Advanced Powder Technology》2021,32(2):504-514
GO and Co(NO3)2 were respectively used as rGO and Co3O4 precursors for preparing magnetically separable Co3O4NPs attached Co3O4NPs@rGO nanocomposites by a straightforward sol–gel technique. To characterize the nanocomposite materials, FESEM, EDX, elemental mapping, XRD, FTIR, Raman spectroscopy, UV–vis, VSM and BET were employed. When exposed to UV rays, the nanocomposite showed extraordinary photocatalytic degradation of MO dye. According to the measurements of photocatalytic activity, the highly efficient photocatalytic efficiency of the nanocomposite could be attributed to preventing electron-hole recombination by highly effective electron transfer between rGO and semiconductor NPs. The nanocomposite succeeded in the efficient degradation of MO dye, even after five photocatalytic cycles. 相似文献
992.
Fahd N. Al-Wesabi Murad A. Almekhlafi Mohammed Abdullah Al-Hagery Mohammad Alamgeer Khalid Mahmood Majdy M. Eltahir Ali M. Al-Sharafi Amin M. El-Kustaban 《计算机、材料和连续体(英文)》2021,69(2):1995-2011
Renewable energy is one of the essential elements of the social and economic development in any civilized country. The use of fossil fuels and the non-renewable form of energy has many adverse effects on the most of ecosystems. Given the high potential of renewable energy sources in Yemen and the absence of similar studies in the region, this study aimed to examine the wind energy potential of Hodeidah-Yemen Republic by analyzing wind characteristics and assessment, determining the available power density, and calculate the wind energy extracted at different heights. The average wind speed of Hodeidah was obtained only for the data currently available for the five years 2005–2009 (due to the current economic and the political situation in Yemen). The results show that the average wind speed in the five years is (25.2 W/m2 at 10 m, 93.9 W/m2 at 30 m, and 173.5 W/m2 at 50 m). The average yearly wind power density (25.2 W/m2 at 10 m, 93.9 W/m2 at 30 m and 173.5 W/m2 at 50m), and the average yearly energy density (220.8 KWh/m2/year at 10 m, 822.6 KWh/m2/year at 30 m and 1519.9 KWh/m2/year at 50 m). This research is a preliminary assessment of the potential of wind energy in Hodeidah, which provides useful information for developing wind energy and an efficient wind approach. According to the International Wind Energy Rating criteria, the region of Hodeidah falls under ‘Class 2’ and is classified as ‘Marginal’ for most of the year. 相似文献
993.
994.
Sadaf Qazi Muhammad Usman Azhar Mahmood Aaqif Afzaal Abbasi Muhammad Attique Yunyoung Nam 《计算机、材料和连续体(英文)》2021,66(1):589-605
Immunization is a noteworthy and proven tool for eliminating lifethreating infectious diseases, child mortality and morbidity. Expanded Program
on Immunization (EPI) is a nation-wide program in Pakistan to implement immunization activities, however the coverage is quite low despite the accessibility of
free vaccination. This study proposes a defaulter prediction model for accurate
identification of defaulters. Our proposed framework classifies defaulters at five
different stages: defaulter, partially high, partially medium, partially low, and
unvaccinated to reinforce targeted interventions by accurately predicting children
at high risk of defaulting from the immunization schedule. Different machine
learning algorithms are applied on Pakistan Demographic and Health Survey
(2017–18) dataset. Multilayer Perceptron yielded 98.5% accuracy for correctly
identifying children who are likely to default from immunization series at different risk stages of being defaulter. In this paper, the proposed defaulters’ prediction
framework is a step forward towards a data-driven approach and provides a set of
machine learning techniques to take advantage of predictive analytics. Hence, predictive analytics can reinforce immunization programs by expediting targeted
action to reduce dropouts. Specially, the accurate predictions support targeted
messages sent to at-risk parents’ and caretakers’ consumer devices (e.g., smartphones) to maximize healthcare outcomes. 相似文献
995.
996.
Muhammad Chawla Hammad Saulat Muhammad Masood Khan Muhammad Mahmood Khan Sikander Rafiq Linjuan Cheng Tanveer Iqbal M. Imran Rasheed Muhammad Zohaib Farooq Muhammad Saeed Nasir M. Ahmad Muhammad Bilal Khan Niazi Sidra Saqib Farrukh Jamil Ahmad Mukhtar Nawshad Muhammad 《化学工程与技术》2020,43(2):184-199
Membrane technology has emerged as a leading tool worldwide for effective CO2 separation because of its well-known advantages, including high surface area, compact design, ease of maintenance, environmentally friendly nature, and cost-effectiveness. Polymeric and inorganic membranes are generally utilized for the separation of gas mixtures. The mixed-matrix membrane (MMM) utilizes the advantages of both polymeric and inorganic membranes to surpass the trade-off limits. The high permeability and selectivity of MMMs by incorporating different types of fillers exhibit the best performance for CO2 separation from natural gas and other flue gases. The recent progress made in the field of MMMs having different types of fillers is emphasized. Specifically, CO2/CH4 and CO2/N2 separation from various types of MMMs are comprehensively reviewed that are closely relevant to natural gas purification and compositional flue gas treatment 相似文献
997.
Golmohammadi Mohammad H. Safavi Hamid R. Sandoval-Solis Samuel Fooladi Mahmood 《Water Resources Management》2021,35(2):593-611
Water Resources Management - Reliability, resilience, and vulnerability (RRV) have been widely used as the performance criteria of a water supply system in the studies conducted over the last three... 相似文献
998.
Zaghari Nayereh Fathy Mahmood Jameii Seyed Mahdi Sabokrou Mohammad Shahverdy Mohammad 《The Journal of supercomputing》2021,77(4):3752-3794
The Journal of Supercomputing - Considering the significant advancements in autonomous vehicle technology, research in this field is of interest to researchers. To drive vehicles autonomously,... 相似文献
999.
1000.
Ramsha Khan Muhammad T. Mehran Salman R. Naqvi Asif H. Khoja Khalid Mahmood Faisal Shahzad Sajjad Hussain 《国际能源研究杂志》2020,44(12):9714-9747
The electrochemical water splitting by using renewable electricity is being considered as a sustainable, clean and considerable source of hydrogen fuel for future transportation and energy applications. The sluggish kinetics at anode and cathode, thus, require plenty of research work on the development of an efficient and stable electrocatalyst, which would provide the enhanced activity of water splitting reaction as well as stability for long-term operation. This review draws a detailed sketch of the progress in the pursuit of replacing noble metals with non-precious perovskite-based substitutes without compromising the key electrocatalyst characteristics. Herein, we critically analysed the latest research work and progress of perovskite oxides for anodic/oxygen reduction reaction/cathodic, including the mechanism behind perovskite oxide catalytic reactions, controlled composition as well as the role of various design strategies to achieve high catalytic performance. Moreover, the article also provides an insight to the associated density functional theory that can provide profound understanding of mechanism, involved behind these reactions and, the need for computational studies to exploit the active area of catalysts. It is believed that this article will assist researchers to explore key area of research in the current generation perovskites that show enhanced catalytic performance as well as to work on unforeseen challenges. 相似文献