全文获取类型
收费全文 | 1579篇 |
免费 | 75篇 |
国内免费 | 12篇 |
专业分类
电工技术 | 17篇 |
综合类 | 4篇 |
化学工业 | 543篇 |
金属工艺 | 97篇 |
机械仪表 | 23篇 |
建筑科学 | 35篇 |
矿业工程 | 2篇 |
能源动力 | 63篇 |
轻工业 | 211篇 |
水利工程 | 6篇 |
石油天然气 | 35篇 |
无线电 | 139篇 |
一般工业技术 | 286篇 |
冶金工业 | 33篇 |
原子能技术 | 11篇 |
自动化技术 | 161篇 |
出版年
2023年 | 21篇 |
2022年 | 62篇 |
2021年 | 87篇 |
2020年 | 65篇 |
2019年 | 76篇 |
2018年 | 101篇 |
2017年 | 65篇 |
2016年 | 67篇 |
2015年 | 53篇 |
2014年 | 79篇 |
2013年 | 135篇 |
2012年 | 75篇 |
2011年 | 103篇 |
2010年 | 71篇 |
2009年 | 61篇 |
2008年 | 45篇 |
2007年 | 29篇 |
2006年 | 33篇 |
2005年 | 20篇 |
2004年 | 33篇 |
2003年 | 27篇 |
2002年 | 25篇 |
2001年 | 11篇 |
2000年 | 16篇 |
1999年 | 21篇 |
1998年 | 24篇 |
1997年 | 21篇 |
1996年 | 12篇 |
1995年 | 18篇 |
1994年 | 15篇 |
1993年 | 12篇 |
1992年 | 14篇 |
1991年 | 13篇 |
1990年 | 8篇 |
1989年 | 9篇 |
1988年 | 9篇 |
1987年 | 15篇 |
1986年 | 14篇 |
1985年 | 13篇 |
1984年 | 9篇 |
1983年 | 7篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1978年 | 7篇 |
1977年 | 6篇 |
1976年 | 12篇 |
1975年 | 5篇 |
1974年 | 8篇 |
1973年 | 6篇 |
排序方式: 共有1666条查询结果,搜索用时 812 毫秒
231.
Enhanced Hydrogen Generation from Empty Fruit Bunches by Charcoal Addition into a Downdraft Gasifier
Hydrogen production by co-gasification of empty fruit bunches of palm oil could be enhanced by adding charcoal. Physiochemical characterization of raw feedstocks was performed to determine their exergy potentiality. The raw feedstocks, gasified charcoal, and the end product of produced gas were analyzed by different techniques. Gasification experiments were performed using a pilot-scale downdraft gasifier. The heating value, composition of product gas, yield of hydrogen, and exergy efficiency were used to verify the improvement of hydrogen production during the co-gasification process. Charcoal with empty fruit bunches of palm oil leads to a much higher yield of hydrogen than lower charcoal ratios or solely empty fruit bunches. This enhanced hydrogen fuel can contribute to future energy demand. 相似文献
232.
233.
234.
Wan-Mohtar Wan Abd Al Qadr Imad Ab Kadir Safuan Halim-Lim Sarina Abdul Ilham Zul Hajar-Azhari Siti Saari Nazamid 《Food science and biotechnology》2019,28(6):1747-1757
Food Science and Biotechnology - In submerged-liquid fermentation, seven key parameters were assessed using one-factor-at-a-time to obtain the highest GABA yield using an industrial soy sauce koji... 相似文献
235.
Afzan Adam Abdul Hadi Abd Rahman Nor Samsiah Sani Zaid Abdi Alkareem Alyessari Nur Jumaadzan Zaleha Mamat Basela Hasan 《计算机、材料和连续体(英文)》2021,67(1):761-787
Boundary effect in digital pathology is a phenomenon where the tissue shapes of biopsy samples get distorted during the sampling process. The morphological pattern of an epithelial layer is greatly affected. Theoretically, the shape deformation model can normalise the distortions, but it needs a 2D image. Curvatures theory, on the other hand, is not yet tested on digital pathology images. Therefore, this work proposed a curvature detection to reduce the boundary effects and estimates the epithelial layer. The boundary effect on the tissue surfaces is normalised using the frequency of a curve deviates from being a straight line. The epithelial layer’s depth is estimated from the tissue edges and the connected nucleolus only. Then, the textural and spatial features along the estimated layer are used for dysplastic tissue detection. The proposed method achieved better performance compared to the whole tissue regions in terms of detecting dysplastic tissue. The result shows a leap of kappa points from fair to a substantial agreement with the expert’s ground truth classification. The improved results demonstrate that curvatures have been effective in reducing the boundary effects on the epithelial layer of tissue. Thus, quantifying and classifying the morphological patterns for dysplasia can be automated. The textural and spatial features on the detected epithelial layer can capture the changes in tissue. 相似文献
236.
H. A. Essawy A. B. Moustafa M. E. Abd El-Aziz A. I. Hussein 《Polymer-Plastics Technology and Engineering》2016,55(11):1124-1130
Solid particles can stabilize emulsions instead of conventional surfactants. Emulsion polymerization of styrene, as an example of polymerizable oil, was processed in the present work after ultrasonication of styrene in water in the presence of silica nanoparticles as stabilizer. Field emission scanning electron microscopy, equipped with energy-dispersive X-ray unit, and transmission electron microscopy confirmed the formation of polystyrene particles covered by a sheath of self-assembled silica. Addition of these hybrids in different loadings (2–14 wt%) to polypropylene and ethylene vinyl acetate copolymer could improve their tensile strength and hardness. The mechanical enrichment could be attributed to the action of the silica shell layer to delay the phase separation process encountered between the polystyrene from one side and polypropylene/ethylene vinyl acetate from other side, which translates into different extents of reinforcements. 相似文献
237.
Hassanin Abdel-Aziz I. M. Abd El-Samie Fathi E. El Banby Ghada M. 《Multimedia Tools and Applications》2019,78(24):34437-34457
Multimedia Tools and Applications - This paper presents an automatic inspection approach for Printed Circuit Boards (PCBs) with accurate determination of the fault location and identification of... 相似文献
238.
Salman Khan Mukhtaj Khan Nadeem Iqbal Mohd Amiruddin Abd Rahman Muhammad Khalis Abdul Karim 《计算机、材料和连续体(英文)》2022,72(2):2243-2258
Piwi-interacting Ribonucleic acids (piRNAs) molecule is a well-known subclass of small non-coding RNA molecules that are mainly responsible for maintaining genome integrity, regulating gene expression, and germline stem cell maintenance by suppressing transposon elements. The piRNAs molecule can be used for the diagnosis of multiple tumor types and drug development. Due to the vital roles of the piRNA in computational biology, the identification of piRNAs has become an important area of research in computational biology. This paper proposes a two-layer predictor to improve the prediction of piRNAs and their function using deep learning methods. The proposed model applies various feature extraction methods to consider both structure information and physicochemical properties of the biological sequences during the feature extraction process. The outcome of the proposed model is extensively evaluated using the k-fold cross-validation method. The evaluation result shows that the proposed predictor performed better than the existing models with accuracy improvement of 7.59% and 2.81% at layer I and layer II respectively. It is anticipated that the proposed model could be a beneficial tool for cancer diagnosis and precision medicine. 相似文献
239.
This study investigates the unsteady electro-osmotic flow (EOF) of a fractional second-grade fluid through a vertical microchannel with convection heat transfer. The fractional Cattaneo heat flux model will be used to modify the heat equation. The solutions for the velocity and the temperature have been derived by employing the Laplace and finite Fourier sine transforms and their numerical inverses. The results show that at the beginning of the time period, the fractional parameter postpones the movement of the fluid. Furthermore, the results show that at the high values of retardation time (non-Newtonian case), the required time for the velocity and the flow rate to reach the steady state increases. Moreover, the heat relaxation time reduces the heat transfer until a critical time, and then the effect reverses. 相似文献
240.
Fatma Hanafy El-Fouly Rabie Abd Ramadan Mohamed I. Mahmoud Moawad I. Dessouky 《Wireless Networks》2018,24(3):735-753
Recently, Multi-sink Wireless Sensor Networks (WSNs) have received more and more attention due to their significant advantages over the single sink WSNs such as improving network throughput, balancing energy consumption, and prolonging network lifetime. Object tracking is regarded as one of the key applications of WSNs due to its wide real-life applications such as wildlife animal monitoring and military area intrusion detection. However, many object tracking researches usually focus on how to track the location of objects accurately, while few researches focus on data reporting. In this work, we propose an efficient data reporting method for object tracking in multi-sink WSNs. Due to the limited energy resource of sensor nodes, it seems especially important to design an energy efficient data reporting algorithm for object tracking in WSNs. Moreover, the reliable data transmission is an essential aspect that should be considered when designing a WSN for object tracking application, where the loss of data packets will affect the accuracy of the tracking and location estimation of a mobile object. In addition, congestion in WSNs has negative impact on the performance, namely, decreased throughput, increased per-packet energy consumption and delay, thus congestion control is an important issue in WSNs. Consequentially, this paper aims to achieve both minimum energy consumption in reporting operation and balanced energy consumption among sensor nodes for WSN lifetime extension. Furthermore, data reliability is considered in our model where the sensed data can reach the sink node in a more reliable way. Finally, this paper presents a solution that sufficiently exerts the underloaded nodes to alleviate congestion and improve the overall throughput in WSNs. This work first formulates the problem as 0/1 Integer Linear Programming problem, and proposes a Reliable Energy Balance Traffic Aware greedy Algorithm in multi-sink WSNs (REBTAM) to solve the optimization problem. Through simulation, the performance of the proposed approach is evaluated and analyzed compared with the previous work which is related to our topic such as DTAR, NBPR, and MSDDGR protocols. 相似文献