全文获取类型
收费全文 | 3700篇 |
免费 | 262篇 |
国内免费 | 10篇 |
专业分类
电工技术 | 38篇 |
综合类 | 8篇 |
化学工业 | 1090篇 |
金属工艺 | 93篇 |
机械仪表 | 100篇 |
建筑科学 | 121篇 |
矿业工程 | 2篇 |
能源动力 | 300篇 |
轻工业 | 471篇 |
水利工程 | 51篇 |
石油天然气 | 28篇 |
武器工业 | 1篇 |
无线电 | 348篇 |
一般工业技术 | 702篇 |
冶金工业 | 91篇 |
原子能技术 | 28篇 |
自动化技术 | 500篇 |
出版年
2024年 | 16篇 |
2023年 | 73篇 |
2022年 | 168篇 |
2021年 | 264篇 |
2020年 | 193篇 |
2019年 | 222篇 |
2018年 | 221篇 |
2017年 | 216篇 |
2016年 | 221篇 |
2015年 | 167篇 |
2014年 | 246篇 |
2013年 | 388篇 |
2012年 | 251篇 |
2011年 | 297篇 |
2010年 | 207篇 |
2009年 | 157篇 |
2008年 | 98篇 |
2007年 | 88篇 |
2006年 | 66篇 |
2005年 | 48篇 |
2004年 | 30篇 |
2003年 | 40篇 |
2002年 | 31篇 |
2001年 | 23篇 |
2000年 | 23篇 |
1999年 | 16篇 |
1998年 | 15篇 |
1997年 | 14篇 |
1996年 | 17篇 |
1995年 | 11篇 |
1994年 | 17篇 |
1993年 | 13篇 |
1992年 | 8篇 |
1991年 | 8篇 |
1990年 | 10篇 |
1989年 | 7篇 |
1988年 | 10篇 |
1987年 | 5篇 |
1986年 | 9篇 |
1985年 | 6篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1982年 | 7篇 |
1981年 | 6篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1976年 | 3篇 |
1974年 | 4篇 |
1973年 | 3篇 |
排序方式: 共有3972条查询结果,搜索用时 15 毫秒
1.
Muhammad Yazid Samatra Nor Qhairul Izzreen Mohd Noor Umi Hartina Mohamad Razali Jamilah Bakar Sharifudin Md. Shaarani 《Comprehensive Reviews in Food Science and Food Safety》2022,21(4):3153-3176
Gelatin is one of the most important multifunctional biopolymers and is widely used as an essential ingredient in food, pharmaceutical, and cosmetics. Porcine gelatin is regarded as the leading source of gelatin globally then followed by bovine gelatin. Porcine sources are favored over other sources since they are less expensive. However, porcine gelatin is religiously prohibited to be consumed by Muslims and the Jewish community. It is predicted that the global demand for gelatin will increase significantly in the future. Therefore, a sustainable source of gelatin with efficient production and free of disease transmission must be developed. The highest quality of Bovidae-based gelatin (BG) was acquired through alkaline pretreatment, which displayed excellent physicochemical and rheological properties. The utilization of mammalian- and plant-based enzyme significantly increased the gelatin yield. The emulsifying and foaming properties of BG also showed good stability when incorporated into food and pharmaceutical products. Manipulation of extraction conditions has enabled the development of custom-made gelatin with desired properties. This review highlighted the various modifications of extraction and processing methods to improve the physicochemical and functional properties of Bovidae-based gelatin. An in-depth analysis of the crucial stage of collagen breakdown is also discussed, which involved acid, alkaline, and enzyme pretreatment, respectively. In addition, the unique characteristics and primary qualities of BG including protein content, amphoteric property, gel strength, emulsifying and viscosity properties, and foaming ability were presented. Finally, the applications and prospects of BG as the preferred gelatin source globally were outlined. 相似文献
2.
Silicon - Following our interest in exotic silylenes, here we compare and contrast 20 novel five-membered cyclic silylenes, including saturated (sila)0–4 cyclopentasilylenes (1–10) and... 相似文献
3.
4.
Mohamad A.A. Attia Roberto Orrù Francesco Delogu Selena Montinaro Sebastiano Garroni Emad M.M. Ewais Giacomo Cao 《Journal of the American Ceramic Society》2015,98(5):1453-1459
The effects produced by annealing Y2O3 nanopowders on their spark plasma sintering (SPS) behavior are systematically investigated in this work. It is found that the annealed powders display higher sinterability with respect to the as‐received ones. Indeed, the maximum densification level reached from pristine powders is about 97.5%, whereas density decreases when further increasing either the sintering temperature or the dwell time. In contrast, the density of SPS products obtained from pretreated powder monotonically increases with temperature and processing time, thus leading to fully dense materials in 30 min at 1050°C and 60 MPa. Correspondingly, it is found that the annealing treatment markedly inhibits grain coarsening during SPS. Thus, dense translucent samples with grain size below 100 nm can be attained from annealed powders. On the other hand, white‐opaque specimens with significantly coarser microstructures (up to 1‐μm‐sized grains) are obtained when pristine powders are directly processed under the same sintering conditions. Furthermore, it is observed that the annealing treatment of SPS samples in air allows for graphite contamination removal, whereas no improvement in term of light transmittance is produced. 相似文献
5.
Nur Lina Rashidah Mohd Rashid Abdullah Abdul Samat Abdul Azim Jais Mahendra Rao Somalu Andanastuti Muchtar Nurul Akidah Baharuddin Wan Nor Roslam Wan Isahak 《Ceramics International》2019,45(6):6605-6615
The performance of low-to-intermediate temperature (400–800?°C) solid oxide fuel cells (SOFCs) depends on the properties of electrolyte used. SOFC performance can be enhanced by replacing electrolyte materials from conventional oxide ion (O2-) conductors with proton (H+) conductors because H+ conductors have higher ionic conductivity and theoretical electrical efficiency than O2- conductors within the target temperature range. Electrolytes based on cerate and/or zirconate have been proposed as potential H+ conductors. Cerate-based electrolytes have the highest H+ conductivity, but they are chemically and thermally unstable during redox cycles, whereas zirconate-based electrolytes exhibit the opposite properties. Thus, tailoring the properties of cerate and/or zirconate electrolytes by doping with rare-earth metals has become a main concern for many researchers to further improve the ionic conductivity and stability of electrolytes. This article provides an overview on the properties of four types of cerate and/or zirconate electrolytes including cerate-based, zirconate-based, single-doped cerate–zirconate and hybrid-doped cerate–zirconate. The properties of the proton electrolytes such as ionic conductivity, chemical stability and sinterability are also systematically discussed. This review further provides a summary of the performance of SOFCs operated with cerate and/or zirconate proton conductors and the actual potential of these materials as alternative electrolytes for proton-conducting SOFC application. 相似文献
6.
7.
Khalid Tauqeer Khan Abdul Nasir Ali Mazhar Adeel Adil ur Rehman Khan Atta Shuja Junaid 《Multimedia Tools and Applications》2019,78(17):24595-24615
Multimedia Tools and Applications - The world is facing many problems including that of traffic congestion. To highlight the issue of traffic congestion worldwide specially in urban areas and to... 相似文献
8.
9.
Abdul Rahman Mohtasebzadeh Longfei Ye Thomas M. Crawford 《International journal of molecular sciences》2015,16(8):19769-19779
We study magnetic-field directed self-assembly of magnetic nanoparticles onto templates recorded on perpendicular magnetic recording media, and quantify feature width and height as a function of assembly time. Feature widths are determined from Scanning Electron Microscope (SEM) images, while heights are obtained with Atomic Force Microscopy (AFM). For short assembly times, widths were ~150 nm, while heights were ~14 nm, a single nanoparticle on average with a 10:1 aspect ratio. For long assembly times, widths approach 550 nm, while the average height grows to 3 nanoparticles, ~35 nm; a 16:1 aspect ratio. We perform magnetometry on these self-assembled structures and observe the slope of the magnetic moment vs. field curve increases with time. This increase suggests magnetic nanoparticle interactions evolve from nanoparticle–nanoparticle interactions to cluster–cluster interactions as opposed to feature–feature interactions. We suggest the aspect ratio increase occurs because the magnetic field gradients are strongest near the transitions between recorded regions in perpendicular media. If these gradients can be optimized for assembly, strong potential exists for using perpendicular recording templates to assemble complex heterogeneous materials. 相似文献
10.