全文获取类型
收费全文 | 354篇 |
免费 | 11篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 93篇 |
金属工艺 | 5篇 |
机械仪表 | 7篇 |
建筑科学 | 16篇 |
矿业工程 | 2篇 |
能源动力 | 12篇 |
轻工业 | 25篇 |
水利工程 | 1篇 |
石油天然气 | 2篇 |
无线电 | 31篇 |
一般工业技术 | 57篇 |
冶金工业 | 31篇 |
原子能技术 | 3篇 |
自动化技术 | 79篇 |
出版年
2024年 | 1篇 |
2023年 | 11篇 |
2022年 | 15篇 |
2021年 | 28篇 |
2020年 | 13篇 |
2019年 | 11篇 |
2018年 | 16篇 |
2017年 | 10篇 |
2016年 | 12篇 |
2015年 | 13篇 |
2014年 | 17篇 |
2013年 | 24篇 |
2012年 | 16篇 |
2011年 | 25篇 |
2010年 | 18篇 |
2009年 | 18篇 |
2008年 | 21篇 |
2007年 | 8篇 |
2006年 | 9篇 |
2005年 | 13篇 |
2004年 | 8篇 |
2003年 | 10篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 5篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 2篇 |
1975年 | 2篇 |
排序方式: 共有365条查询结果,搜索用时 446 毫秒
361.
An-Yi Chang Samar S. Sandhu P. U. Ashvin I. Fernando Gilbert. K. Kosgei Caitlin Bresnahan Jared S. Cobb Jose F. Morales Jiachi Zhou Shichao Ding Ashley Hanna Johanna Jernberg Joseph Wang 《Advanced functional materials》2023,33(42):2303968
While fluoride ions (F−) are abundant across environmental and biological systems, common procedures and potentiometric sensors for quantifying aqueous F− are inefficient, time-consuming, and suffer from poor pH resiliency and high detection limits. Herein, this work reports a new di-boronic acid-functionalized ferrocene (FDBA) molecular receptor for noncovalent F− recognition, toward the development of a solid-state miniaturized voltammetric fluoride sensor capable of direct and reversible F− detection in drinking water (DW) (pH 6) and community water (pH 7.6–9.1) over the µg L−1–mg L−1 range. The associated sensing mechanism is enabled by the conformational change of FDBA from the open (charge-repelled) to closed (π-dimerized) conformation, which is facilitated by the unique linkage of two electron-accepting phenylboronic acid moieties with the electron-donating ferrocene moiety using rigid conjugated amide linkers. The square wave voltammetric (SWV) oxidation current response of the FDBA-based fluoride sensor is spectroscopically investigated, suggesting a combination of electrooxidation-triggered conformational change of FDBA on a nanocarbon-modified electrode, F− anion–π interactions, and resulting electron transfer between F− and FDBA. The performance of the voltammetric fluoride sensor is compared to that of a commercial liquid junction-based fluoride ion-selective electrode (F-ISE), and of a solid-contact (SC) F-ISE sensor chip, demonstrating significant advantages versus traditional potentiometric F-ISEs. 相似文献
362.
Cellulose acetate (CA) is known for its low adsorption affinity toward dyes, hence this study aims to improve its adsorption affinity toward cationic dyes by introducing Cloisite 30B grafted with polyacrylic acid (C30B-g-PAA). C30B-g-PAA was synthesized by grafting polyacrylic acid (PAA) onto Cloisite 30B (C30B) using in-situ reversible addition fragmentation chain transfer (RAFT) polymerization. Different weight ratios of unmodified (raw) and modified (C30B-g-PAA) C30B (0, 25, and 50 wt%) were incorporated into CA matrices to prepare a series of CA nanocomposite films. The results showed that the adsorption affinity of the prepared nanocomposite films increased toward cationic methylene blue (MB) dye with incorporating either unmodified or modified C30B, but a significant improvement was observed with the incorporating C30B-g-PAA with a maximum adsorption capacity of 53 mg/g for a load of 50 wt%. This indicates that the surface modification of C30B with PAA was effective in enhancing the adsorption efficacy of CA. The kinetic and isotherm studies showed that the adsorption behavior of CA nanocomposite film with 50 wt% of C30B-g-PAA followed pseudo-second-order and Langmuir isothermal model. Regeneration study showed good reusability of CA nanocomposite film with 50 wt% of C30B-g-PAA. These results demonstrate that the nanocomposite film with 50 wt% of C30B-g-PAA can be used as a highly efficient, easy to separate, and reusable adsorbent material to remove MB dye from wastewater. 相似文献
363.
Samir A.A. El-Gendy Mohamed A.M. Alsafy Catrin S. Rutland Samar M. Ez Elarab Hanan H. Abd-Elhafeez Basma M. Kamal 《Microscopy research and technique》2023,86(1):53-62
The present study describes the morphological characteristics of the camel heart Ossa cordis, and os aorta using computed tomography soft tissue window (CT) alongside 3D render volume reconstructions and light microscopy. The current study techniques demonstrated the Ossa cordis and os aorta in the cardiac window with more precision than the black and white (ghost), and angiography images. Transverse and sagittal CT images additionally demonstrated the presence of Ossa cordis and os aorta. This study is the first to record two small Ossa cordis sinistrum and one os aorta in the camel heart, in addition to the more commonly observed singular, large, os cordis dextrum. The os cordis dextrum was always located in the upper part of the interventricular septum, near to its junction with the atrium, forming an elongated rectangular shape when observed transversally. The wider cranial part was composed from bone, whereas the caudal aspect was narrow and contained both bone and cartilage. Light microscopy identified that the os cordis dextrum consisted of trabecular bone, marrow spaces, and hyaline cartilage. Two Ossa cordis sinistrum were detected on the left side of the heart, one in the right fibrous ring and another in the interventricular septum, microscopy showed that both contained only trabecular bone with osteocytes, osteoblasts, and osteoclasts. At the level of ascending aorta, there was also trabecular bone containing osteocytes, an os aorta. 相似文献
364.
Reda M. El‐Shishtawy M. Abdel Salam M.A. Gabal Abdullah M. Asiri 《Polymer Composites》2012,33(4):532-539
New electromagnetic nanocomposites were prepared from polyaniline (PANI)/oxidized single‐walled carbon nanotubes (OxSWCNTs)/NiFe2O4 by in situ polymerization of aniline using hexanoic acid as a soft template. OxSWCNT and NiFe2O4 were prepared first so as to be used in the formulation of PANI composites. Transmission electron microscope (TEM) results revealed the formation of PANI nanoparticles of 60 nm diameter, OxSWCNT of 24 nm, and NiFe2O4 of 54 nm. Also, TEM image of the ternary composite indicated agglomerative coating of PANI appearing as a gray shells and black core of NiFe2O4 with widening the diameter of OxSWCNT to be around 66 nm. Dc conductivity was measured as a function of temperature. Magnetic susceptibility was measured as a function of temperature and magnetic field intensity. All samples revealed NiFe2O4‐dependent ferromagnetism. The activation energies for dc conductivity suggest that the conductivity is owing to hopping conduction mechanism. A synergistic effect between NiFe2O4 and PANI/OxSWCNT is observed. POLYM. COMPOS.,, 2012. © 2012 Society of Plastics Engineers 相似文献
365.
Mohammed Reda Haddouche 《亚洲传热研究》2023,52(6):3967-3988
The main purpose of this study is to investigate numerically the thermal performance of a parabolic trough solar collector's absorber tube that contains a novel kind of inserts with the objective to improve the heat transfer between the heat transfer fluid and the absorber tube. In the first part of this paper, the diameter and the length of the cylindrical inserts are investigated based on finite volume method and Monte Carlo ray tracing method for Reynolds number ranges from 2.36 × 104 to 7.09 × 104. In the second part, the eccentricity of the cylindrical inserts is investigated under the same operating conditions. The Therminol®VP1 is the HTF that is used in this investigation's intermediate fluid. The numerical simulation indicates that the perturbators enhance the thermal behavior of the receiver and reduces the absorber tube's temperature difference. 相似文献