全文获取类型
收费全文 | 5578篇 |
免费 | 507篇 |
国内免费 | 64篇 |
专业分类
电工技术 | 63篇 |
综合类 | 22篇 |
化学工业 | 1253篇 |
金属工艺 | 85篇 |
机械仪表 | 279篇 |
建筑科学 | 109篇 |
矿业工程 | 8篇 |
能源动力 | 343篇 |
轻工业 | 732篇 |
水利工程 | 67篇 |
石油天然气 | 31篇 |
武器工业 | 1篇 |
无线电 | 726篇 |
一般工业技术 | 1263篇 |
冶金工业 | 106篇 |
原子能技术 | 59篇 |
自动化技术 | 1002篇 |
出版年
2024年 | 31篇 |
2023年 | 204篇 |
2022年 | 442篇 |
2021年 | 770篇 |
2020年 | 464篇 |
2019年 | 528篇 |
2018年 | 482篇 |
2017年 | 411篇 |
2016年 | 403篇 |
2015年 | 246篇 |
2014年 | 304篇 |
2013年 | 406篇 |
2012年 | 252篇 |
2011年 | 301篇 |
2010年 | 173篇 |
2009年 | 154篇 |
2008年 | 99篇 |
2007年 | 96篇 |
2006年 | 44篇 |
2005年 | 35篇 |
2004年 | 41篇 |
2003年 | 30篇 |
2002年 | 20篇 |
2001年 | 8篇 |
2000年 | 11篇 |
1999年 | 16篇 |
1998年 | 24篇 |
1997年 | 13篇 |
1996年 | 12篇 |
1995年 | 19篇 |
1994年 | 12篇 |
1993年 | 14篇 |
1992年 | 10篇 |
1991年 | 11篇 |
1990年 | 3篇 |
1989年 | 8篇 |
1988年 | 9篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 6篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1961年 | 1篇 |
排序方式: 共有6149条查询结果,搜索用时 31 毫秒
201.
This study presents a group skip-lot sampling plan using resampling (SkSP-R) for accelerated life tests. It is assumed that the lifetime of a product follows Weibull distribution with known shape parameter under the use condition, while the scale parameter can be obtained from acceleration factor. The plan parameters are determined through a non-linear optimisation problem for fixed values of producer’s risk and consumer’s risk. The advantages of the proposed plan over the existing one are explained with some practical examples. 相似文献
202.
203.
Dost Muhammad Khan Syed M. Salman 《Fullerenes, Nanotubes and Carbon Nanostructures》2016,24(3):202-212
Novel buckypaper of polyvinyl chloride (PVC) and poly(styrene-co-maleic anhydride) (PSMA) intercalated with carbon nanotube (CNT) and graphene oxide-CNT (GO-CNT) nanobifiller was prepared using resin infiltration technique. Two series of buckypaper were prepared with varying CNT and GO-CNT contents. According to field emission scanning electron microscopy, PVC/SMA/CNT 0.1 showed porous morphology while PVC/PSMA/GO-CNT 0.1 revealed unique sort of island-nodule morphology. Tmax of PVC/PSMA/GO-CNT 0.1 was 561°C while PVC/PSMA/CNT 0.1 depicted relatively lower value (552°C). Tg of PVC/PSMA/GO-CNT 0.1 was also increased to 294°C. Peak heat release rate of poly(methyl methacrylate-co-methacrylic acid)/polyamide 6/montmorillonite-modified GO was decreased from 322 to 209 kW/m2 (65%) with 0.03–0.3 g GO-CNT loading. 相似文献
204.
Anum Kayani Muhammad Asim Raza Arsalan Raza Tajamal Hussain Muhammad Sarfraz Akram Aneela Sabir Atif Islam Bilal Haider Rafi Ullah Khan Sang Hyun Park 《International journal of molecular sciences》2021,22(5)
Chitosan and polyethylene glycol (PEG-600) membranes were synthesized and crosslinked with 3-aminopropyltriethoxysilane (APTES). The main purpose of this research work is to synthesize RO membranes which can be used to provide desalinated water for drinking, industrial and agricultural purposes. Hydrogen bonding between chitosan and PEG was confirmed by displacement of the hydroxyl absorption peak at 3237 cm−1 in pure chitosan to lower values in crosslinked membranes by using FTIR. Dynamic mechanical analysis revealed that PEG lowers Tg of the modified membranes vs. pure chitosan from 128.5 °C in control to 120 °C in CS-PEG5. SEM results highlighted porous and anisotropic structure of crosslinked membranes. As the amount of PEG was increased, hydrophilicity of membranes was increased and water absorption increased up to a maximum of 67.34%. Permeation data showed that flux and salt rejection value of the modified membranes was increased up to a maximum of 80% and 40.4%, respectively. Modified films have antibacterial properties against Escherichia coli as compared to control membranes. 相似文献
205.
Ahmad Awais Ahmad Mudassar Habib Muhammad Asif Sarwar Shahzad Chaudhry Junaid Latif Muhammad Ahsan Dar Saadat Hanif Shahid Muhammad 《The Journal of supercomputing》2019,75(4):2269-2288
The Journal of Supercomputing - The main challenge in database-as-a-service is the security and privacy of data because service providers are not usually considered as trustworthy. So, the data... 相似文献
206.
Huang Wei-Ran Yu Cheng-Xin Lu Yi-Ruo Muhammad Hassan Wang Jin-Long Liu Jian-Wei Yu Shu-Hong 《Nano Research》2019,12(6):1483-1488
Nano Research - In the past two decades, the field of surface-enhanced Raman scattering (SERS) has flourished and many rational strategies have been reported for the successful construction of SERS... 相似文献
207.
Sarwar Sohail Qayyum Zia Ul García-Castro Raúl Safyan Muhammad Munir Rana Faisal 《Multimedia Tools and Applications》2019,78(24):34745-34771
Multimedia Tools and Applications - Enhancing the degree of learner productivity, one of the major challenges in E-Learning systems, may be catered through effective personalization, adaptivity and... 相似文献
208.
Spherulitic formation and characterization of partially fluorinated copolymers and their nanohybrids with functional fillers
下载免费PDF全文
![点击此处可从《Polymer Engineering and Science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Muhammad Abdullah Al Mamun Yusuke Kasahara Taira Tasaki Atsuhiro Fujimori 《Polymer Engineering and Science》2017,57(2):161-171
Poly[vinylidenefluoride‐co‐(tetrafluoroethylene)] (P(VDF‐TeFE)) exhibited clear spherulitic texture with negative birefringence. The number and growth rates of the spherulites decreased at high crystallization temperature than at low crystallization temperature. Nonetheless, overall larger spherulites were found at high crystallization temperature and the brightness of the spherulites increased very fast at low crystallization temperature, thereafter it seemed as diminution of birefringence. AFM was used to investigate the impact of organo modified nanodiamond(ND) on spherulitic textures, lamellar thickness, and thickness distribution of P(VDF‐TeFE) copolymer. Poly[ethylene‐co‐(tetrafluoroethylene)] (ETFE) also confirmed spherulites structure and the boundaries could be clearly observed. By incorporation of the organo modified nanodiamond (ND) and organo‐modified montmorillonite (MMT) in fluropolymer matrix, it was found that spherulitic texture was seriously disordered and their nanohybrids was found only to have poorly developed spherulite structure. Both of the nanohybrids samples show better crystallization temperature as compared to their neat copolymer samples. Furthermore, the incorporation of nanoparticles decreased the size of the spherulites. POLYM. ENG. SCI., 57:161–171, 2017. © 2016 Society of Plastics Engineers 相似文献
209.
Faheem Ullah Fatima Javed Muhammad Bisyrul Hafi Othman Zulkifli Ahmad 《国际聚合物材料杂志》2017,66(16):824-834
There is an urgent need to treat diabetes, and therefore, this work reports on a chitosan-built hydrogel functionalized by a glucose sensing moiety, which simulates pancreatic activity. The effect of external stimuli on various internal properties was investigated to establish the action of the hydrogel. The model drugs, fluorescein (D1) and rhodamine (D2), with a diol architecture, were investigated spectroscopically with 75.94% loading and 65.63% release. Consequently, a ligand to glucose ratio of 2:1 in comparison with a ligand to model drug ratio of 1:1 was addressed. The system was expected to lead to findings on applications for the self-controlled release of insulin in response to blood glucose levels. 相似文献
210.
Muhammad G. Abd El-Moghny Hafsa H. Alalawy Ahmad M. Mohammad Amina A. Mazhar Mohamed S. El-Deab Bahgat E. El-Anadouli 《International Journal of Hydrogen Energy》2017,42(16):11166-11176
Research is moving rapidly to sustain convenient energy resources fulfilling the global climate legislations. Herein, a novel catalyst of platinum nanoparticles (PtNPs) dispersed onto polyaniline (PANi) is recommended for formic acid electro-oxidation (FAO); the fundamental anodic reaction in direct formic acid fuel cells (DFAFCs). The catalyst's preparation scheme allows a sequential electrodeposition of fibril PANi and spherical PtNPs (ca. 65 nm in size) on a glassy carbon (GC) substrate and permits a precise control over the deposition sequence and loading. Interestingly, incorporation of PANi into the catalyst's ingredients can significantly (ca. 16 times) improve the catalytic activity of the catalyst towards FAO by shifting the mechanism towards the desirable dehydrogenation pathway and mitigating the undesirable poisoning dehydration pathway. The catalytic efficiency is tuned by manipulating the deposition order and loading of different catalyst's ingredients. Several techniques are employed to confirm the successful deposition of the catalyst and to evaluate its morphology, composition and crystal structure. While PtNPs are essential for FA adsorption, PANi improves the dispersion of PtNPs and mediates FAO to facilitate the charge transfer and mitigate CO poisoning. A promising catalytic stability is achieved in a long continuous (150 CVs) electrolysis experiment. 相似文献