全文获取类型
收费全文 | 510589篇 |
免费 | 36138篇 |
国内免费 | 19272篇 |
专业分类
电工技术 | 26242篇 |
技术理论 | 50篇 |
综合类 | 32208篇 |
化学工业 | 82419篇 |
金属工艺 | 29661篇 |
机械仪表 | 30906篇 |
建筑科学 | 36599篇 |
矿业工程 | 14947篇 |
能源动力 | 12916篇 |
轻工业 | 32094篇 |
水利工程 | 9337篇 |
石油天然气 | 29360篇 |
武器工业 | 3476篇 |
无线电 | 55405篇 |
一般工业技术 | 62448篇 |
冶金工业 | 24902篇 |
原子能技术 | 4589篇 |
自动化技术 | 78440篇 |
出版年
2024年 | 1757篇 |
2023年 | 6692篇 |
2022年 | 12029篇 |
2021年 | 16777篇 |
2020年 | 12835篇 |
2019年 | 10413篇 |
2018年 | 24450篇 |
2017年 | 25214篇 |
2016年 | 21147篇 |
2015年 | 17521篇 |
2014年 | 21474篇 |
2013年 | 25616篇 |
2012年 | 30589篇 |
2011年 | 39144篇 |
2010年 | 34356篇 |
2009年 | 30468篇 |
2008年 | 31181篇 |
2007年 | 31172篇 |
2006年 | 24656篇 |
2005年 | 22700篇 |
2004年 | 15520篇 |
2003年 | 14175篇 |
2002年 | 12722篇 |
2001年 | 11030篇 |
2000年 | 10934篇 |
1999年 | 11720篇 |
1998年 | 9010篇 |
1997年 | 7660篇 |
1996年 | 7315篇 |
1995年 | 6010篇 |
1994年 | 4871篇 |
1993年 | 3269篇 |
1992年 | 2652篇 |
1991年 | 1959篇 |
1990年 | 1531篇 |
1989年 | 1257篇 |
1988年 | 1041篇 |
1987年 | 663篇 |
1986年 | 517篇 |
1985年 | 321篇 |
1984年 | 252篇 |
1983年 | 198篇 |
1982年 | 163篇 |
1981年 | 100篇 |
1980年 | 116篇 |
1979年 | 58篇 |
1968年 | 46篇 |
1965年 | 46篇 |
1955年 | 63篇 |
1954年 | 68篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Peiying Wang Juanli Zhao Yun Fan Wei Zhang Yuanyuan Cui Liangmiao Zhang Bin Liu Hongqiang Nian Yiran Li 《Ceramics International》2021,47(11):15023-15029
In this work, the composition-dependent point defect types and formation energies of RE2Hf2O7 (RE = La, Ce, Pr, Nd, Pm, Sm, Eu and Gd) as well as the oxygen diffusion behavior are systematically investigated by first-principles calculations. The possible defect reactions and dominant defect complexes under stoichiometric and non-stoichiometric conditions are revealed. It is found that O Frenkel pairs are the predominant defect in stoichiometric pyrochlore hafnates. Hf-RE cation anti-site defects, accompanied by RE vacancies and/or oxygen interstitials, are stable in the non-stoichiometric case of HfO2 excess. On the other hand, RE-Hf anti-site defects together with oxygen vacancies and/or RE interstitials are preferable in the case of RE2O3 excess. The energy barriers for the migration along the VO48f - VO48f pathway of pyrochlore hafnates were calculated to be between 0.81 eV and 0.89 eV. Based on these results, a defect engineering strategy is proposed and the pyrochlore hafnates investigated here are predicted to exhibit potential oxygen ionic conductivity. 相似文献
12.
Neural Processing Letters - The boundedness and the global Mittag-Leffler synchronization (GMLS) of fractional-order inertial Cohen–Grossberg neural networks (CGNNS) with time delays are... 相似文献
13.
Applied Composite Materials - In this paper, the low-velocity impact deformation behavior of biaxial warp-knitted flexible composite was investigated. A simplified finite element model (FEM) of the... 相似文献
14.
Jing-jie Xie Xiao-Li Zou Yan-ping Li Zhuang-Li Kang Han-jun Ma 《International Journal of Food Science & Technology》2022,57(4):2459-2466
The effects of high-pressure-modified soy 11S globulin (0.1, 200, and 400 MPa) on the gel properties, water-holding capacity, and water mobility of pork batter were investigated. The high-pressure-modified soy 11S globulin significantly increased (P < 0.05) the emulsion stability, cooking yield, hardness, springiness, chewiness, resilience, cohesiveness, the a* and b* values, and the G′ and G′′ values of pork batter at 80 °C, compared with those of 0.1 MPa-modified globulin. In contrast, the centrifugal loss and initial relaxation time of T2b, T21, and T22 significantly decreased (P < 0.05). Meanwhile, the microstructure was denser, and the voids were smaller and more uniform compared with those of 0.1 MPa-modified globulin. In addition, the sample with 11S globulin modified at 400 MPa had the best water-holding capacity, gel structure, and gel properties among the samples. Overall, the use of high-pressure-modified soy 11S globulin improved the gel properties and water-holding capacity of pork batter, especially under 400 MPa. 相似文献
15.
Ligang Yu Yong Li Yukun Yang Caixia Guo Meiping Li 《International Journal of Food Science & Technology》2022,57(7):4646-4655
This study investigated the inhibitory effects of curcumin and piperine on fluorescent advanced glycation end products (fAGEs) formation in a bovine serum albumin (BSA)–fructose model. Model systems of BSA and fructose were prepared, and curcumin or piperine was added. fAGEs and BSA oxidation product (dityrosine, kynurenine and N'-formylkynurenine) contents were determined. The results showed that fAGEs content decreased with increasing concentration of curcumin and piperine (P < 0.05). Addition of curcumin and piperine at 160 µg mL−1 could inhibit fluorescent AGEs by 100% and 93% respectively. Dityrosine and N'-formylkynurenine contents decreased as curcumin and piperine concentration increased (P < 0.05). Furthermore, the result of principal component analysis indicated that curcumin and piperine markedly impeded BSA oxidation, resulting in a lower level of fAGEs in model systems. Therefore, adding curcumin and piperine may facilitate reduced fAGEs levels in BSA–fructose model. 相似文献
16.
Yuhang Xing Ruyi Li Lu Xue Mianhong Chen Xuli Lu Zhihao Duan Wei Zhou Jihua Li 《International Journal of Food Science & Technology》2022,57(8):5268-5279
Mangiferin (MGF) is a phenolic compound isolated from mango, but its poor solubility significantly limits its use. In this study, MGF was embedded into the inner aqueous phase of W1/O/W2 emulsions. Firstly, the dissolution method of MGF was determined. MGF remained stable in solution with pH 13 at 30 min, and its solubility reached 10 mg mL−1. When the pH of MGF solutions was adjusted from pH 13 to pH 6, MGF did not immediately crystallise, providing sufficient time to construct the MGF-loaded W1/O/W2 emulsions. Subsequently, the MGF-loaded W1/O/W2 emulsions were constructed using polyglycerol polyricinoleate (PGPR) and calcium caseinate (CAS). The formation and stability of the W1/O/W2 emulsions were investigated. The MGF-loaded W1/O/W2 emulsions stabilised with 1% PGPR and 1% – 3% CAS exhibited a low viscosity, limited loading capacity, and poor stability. Conversely, the MGF-loaded W1/O/W2 emulsions stabilised by 3%PGPR–3%CAS exhibited optimal loading capacity (encapsulation efficiency = 95.31% and loading efficiency = 0.91%) and stability, which was attributed to the fact that high viscosity and gel state retarded the migration of inner aqueous phase. These results indicated that the W1/O/W2 emulsions stabilised by PGPR and CAS may be a potential alternative for encapsulating mangiferin. 相似文献
17.
Chenchen Zhou Jia Man Haibo Yu He Xia Luming Man Bin Qi Jianfeng Li 《Ceramics International》2021,47(8):10866-10872
Ceramic microparticles have great potentials in various fields such as materials engineering, biotechnology, microelectromechanical systems, etc. Morphology of the microparticle performs an important role on their application. To date, it remains difficult to find an effective and controllable way for fabricating nonspherical ceramic microparticles with 3D features. This work demonstrates a method that combines UV light lithography and single emulsion opaque-droplet-templated microfluidic molding to prepare the crescent-shaped ceramic microparticles. By tailoring the intensity of UV light and flow rate of fluid, the shapes of microparticles are accordingly tuned. Therefore, varieties of crescent-shaped microparticles and their variations have been fabricated. After sintering, the crescent-shaped alumina ceramic microparticles were obtained. Benefitting from the light absorption and scattering behavior of most ceramic nanoparticles, this system can serve as a general platform to produce crescent-shaped microparticles made from different materials, and hold great potentials for applications in microrobotics, structural materials in MEMS, and biotechnology. 相似文献
18.
19.
20.