全文获取类型
收费全文 | 60290篇 |
免费 | 5439篇 |
国内免费 | 2152篇 |
专业分类
电工技术 | 2960篇 |
技术理论 | 7篇 |
综合类 | 3237篇 |
化学工业 | 11018篇 |
金属工艺 | 3340篇 |
机械仪表 | 3739篇 |
建筑科学 | 3709篇 |
矿业工程 | 1595篇 |
能源动力 | 1945篇 |
轻工业 | 4109篇 |
水利工程 | 814篇 |
石油天然气 | 3155篇 |
武器工业 | 464篇 |
无线电 | 7641篇 |
一般工业技术 | 8855篇 |
冶金工业 | 3114篇 |
原子能技术 | 781篇 |
自动化技术 | 7398篇 |
出版年
2024年 | 273篇 |
2023年 | 1066篇 |
2022年 | 1753篇 |
2021年 | 2529篇 |
2020年 | 1913篇 |
2019年 | 1635篇 |
2018年 | 1928篇 |
2017年 | 2184篇 |
2016年 | 2074篇 |
2015年 | 2483篇 |
2014年 | 3182篇 |
2013年 | 3923篇 |
2012年 | 4063篇 |
2011年 | 4533篇 |
2010年 | 3679篇 |
2009年 | 3527篇 |
2008年 | 3361篇 |
2007年 | 3154篇 |
2006年 | 2985篇 |
2005年 | 2519篇 |
2004年 | 1857篇 |
2003年 | 1608篇 |
2002年 | 1554篇 |
2001年 | 1340篇 |
2000年 | 1332篇 |
1999年 | 1310篇 |
1998年 | 1206篇 |
1997年 | 961篇 |
1996年 | 877篇 |
1995年 | 651篇 |
1994年 | 562篇 |
1993年 | 387篇 |
1992年 | 307篇 |
1991年 | 226篇 |
1990年 | 194篇 |
1989年 | 162篇 |
1988年 | 132篇 |
1987年 | 71篇 |
1986年 | 83篇 |
1985年 | 44篇 |
1984年 | 42篇 |
1983年 | 41篇 |
1982年 | 29篇 |
1981年 | 20篇 |
1980年 | 16篇 |
1979年 | 12篇 |
1977年 | 11篇 |
1976年 | 19篇 |
1974年 | 8篇 |
1970年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
Bing Yang Yu Zhou Wenjie Yu Song Zhang Hongxiang Chen Ju Ye 《Polymer International》2019,68(4):675-683
In order to improve the dispersity and stability of the nano‐SiO2 aqueous system with high solid content, a kind of polyacrylic acid dispersant with methoxysilicon end groups (KH590‐PAA) was synthesized by photopolymerization of acrylic acid (AA) initiated with (3‐mercaptopropyl)trimethoxysilane (KH590). After adding KH590‐PAA into the nano‐SiO2 aqueous dispersion system (20 wt% solid content), the viscosity and the curing time of the system were measured with a rotational viscometer and the inverted bottle method. Moreover, the dispersion mechanism of KH590‐PAA for the nano‐SiO2 aqueous system was researched by measuring the adsorption capacity, the particle size and the zeta potential of the nanoparticles with a conductivity meter, dynamic light scattering, SEM and TEM, respectively. The results showed that the methoxysilicon groups in KH590‐PAA could react with hydroxyl groups on the surface of nano‐SiO2 in the process of stirring, which enhanced the adsorption capacity of the dispersant and then increased the surface charge of the particles. Therefore, electrostatic repulsion and steric hindrance effects between the SiO2 nanoparticles could be further enhanced by adding the KH590‐PAA dispersant, and then the nano‐SiO2 aqueous system exhibited better dispersity and stability. Besides, the dispersion properties of SiO2 nanoparticles in water were closely related to the addition amount and the molecular weight of the KH590‐PAA dispersant. © 2018 Society of Chemical Industry 相似文献
22.
23.
24.
25.
Journal of Computer Science and Technology - DOACROSS loops are significant parts in many important scientific and engineering applications, which are generally exploited pipeline/wave-front... 相似文献
26.
Shibo Lv Yuyang Miao Dr. Dapeng Liu Prof. Fengling Song 《Chembiochem : a European journal of chemical biology》2020,21(15):2098-2110
Photothermal therapy (PTT) has attracted great attention due to its noninvasive and effective use against cancer. Various photothermal agents (PTAs) including organic and inorganic PTAs have been developed in the last decades. Organic PTAs based on small-molecule dyes exhibit great potential for future clinical applications considering their good biocompatibility and easy chemical modification or functionalization. In this review, we discuss the recent progress of organic PTAs based on small-molecule dyes for enhanced PTT. We summarize the strategies to improve the light penetration of PTAs, methods to enhance their photothermal conversion efficiency, how to optimize PTAs’ delivery into deep tumors, and how to resist photobleaching under repeated laser irradiation. We hope that this review can rouse the interest of researchers in the field of PTAs based on small-molecule dyes and help them to fabricate next-generation PTAs for noninvasive cancer therapy. 相似文献
27.
28.
29.
Thermal barrier coatings (TBCs) produced by electron beam physical vapor deposition (EB-PVD) or plasma spray (PS) usually suffer from molten calcium-magnesium-alumino-silicate (CMAS) attack. In this study, columnar structured YSZ coatings were fabricated by plasma spray physical vapor deposition (PS-PVD). The coatings were CMAS-infiltrated at 1250?°C for short terms (1, 5, 30?min). The wetting and spreading dynamics of CMAS melt on the coating surface was in-situ investigated using a heating microscope. The results indicate that the spreading evolution of CMAS melt can be described in terms of two stages with varied time intervals and spreading velocities. Besides, the PS-PVD columnar coating (~100?μm thick) was fully penetrated by CMAS melt within 1?min. After the CMAS attack for 30?min, the original feathered-YSZ grains (tetragonal phase) in both PS-PVD and EB-PVD coatings were replaced by globular shaped monoclinic ZrO2 grains in the interaction regions. 相似文献
30.