全文获取类型
收费全文 | 119491篇 |
免费 | 7302篇 |
国内免费 | 3403篇 |
专业分类
电工技术 | 4981篇 |
技术理论 | 10篇 |
综合类 | 5566篇 |
化学工业 | 17581篇 |
金属工艺 | 4632篇 |
机械仪表 | 5157篇 |
建筑科学 | 6558篇 |
矿业工程 | 2361篇 |
能源动力 | 2557篇 |
轻工业 | 8151篇 |
水利工程 | 2050篇 |
石油天然气 | 3831篇 |
武器工业 | 563篇 |
无线电 | 10495篇 |
一般工业技术 | 12806篇 |
冶金工业 | 26389篇 |
原子能技术 | 1003篇 |
自动化技术 | 15505篇 |
出版年
2024年 | 314篇 |
2023年 | 1405篇 |
2022年 | 2346篇 |
2021年 | 3256篇 |
2020年 | 2453篇 |
2019年 | 1977篇 |
2018年 | 2688篇 |
2017年 | 2982篇 |
2016年 | 3318篇 |
2015年 | 3666篇 |
2014年 | 4193篇 |
2013年 | 4805篇 |
2012年 | 6927篇 |
2011年 | 7634篇 |
2010年 | 5027篇 |
2009年 | 4948篇 |
2008年 | 4809篇 |
2007年 | 4484篇 |
2006年 | 4226篇 |
2005年 | 6424篇 |
2004年 | 4936篇 |
2003年 | 4092篇 |
2002年 | 2727篇 |
2001年 | 2429篇 |
2000年 | 2093篇 |
1999年 | 2699篇 |
1998年 | 8235篇 |
1997年 | 5519篇 |
1996年 | 4097篇 |
1995年 | 2726篇 |
1994年 | 2144篇 |
1993年 | 1917篇 |
1992年 | 828篇 |
1991年 | 728篇 |
1990年 | 664篇 |
1989年 | 609篇 |
1988年 | 541篇 |
1987年 | 404篇 |
1986年 | 335篇 |
1985年 | 285篇 |
1984年 | 149篇 |
1983年 | 153篇 |
1982年 | 215篇 |
1981年 | 251篇 |
1980年 | 270篇 |
1979年 | 99篇 |
1978年 | 126篇 |
1977年 | 731篇 |
1976年 | 1529篇 |
1975年 | 124篇 |
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
1.
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
2.
Prof. Andrea Baier Dr. Anne Kokel Dr. William Horton Ewa Gizińska Dr. Garima Pandey Prof. Ryszard Szyszka Prof. Béla Török Prof. Marianna Török 《ChemMedChem》2021,16(12):1927-1932
A set of novel hydrazone derivatives were synthesized and analyzed for their biological activities. The compounds were tested for their inhibitory effect on the phosphorylating activity of the protein kinase CK2, and their antioxidant activity was also determined in three commonly used assays. The hydrazones were evaluated for their radical scavenging against the DPPH, ABTS and peroxyl radicals. Several compounds have been identified as good antioxidants as well as potent protein kinase CK2 inhibitors. Most hydrazones containing a 4-N(CH3)2 residue or perfluorinated phenyl rings showed high activity in the radical-scavenging assays and possess nanomolar IC50 values in the kinase assays. 相似文献
3.
Marcus Reppich Zdeněk Jegla Jakob Grondinger Yaovi Ouézou Azouma Vojtěch Turek 《化学,工程师,技术》2021,93(10):1581-1589
This study investigates the behavior of fruit and vegetable samples during drying. The experimental data are fitted to several different thin-layer drying models. Regression analysis is used to determine model parameters, while statistical indicators serve to evaluate the goodness of fit. The power function model gives the best fit for all examined samples. Based on this model, different drying and heat storage technologies can be combined to ensure that the required residual moisture content of an agricultural product is reached. It is demonstrated on the case of a specific Togolese processing plant that under favorable conditions, fossil fuel consumption can be decreased by 33 %. 相似文献
4.
KH550, KH560, CTAB, and F127 were adopted to modify silicon (Si) to improve the dispersity and stability of Si in the polyacrylonitrile/dimethyl sulfoxide (PAN/DMSO) polymer solutions. The influence of surfactants on rheological behaviors of PAN/DMSO/Si blending polymer solutions was investigated by an advanced solution and melt rotation rheometer. The homogeneity and stability were also studied. The results showed that the surfactants could change the viscosity dependence of blending polymer solutions on shear rate, temperature and storage time by increase the steric hindrance of Si. Among the four solutions, PAN/DMSO/Si blending polymer solution with F127 exhibited the lowest viscosity, activation energy and the smallest structural viscosity index and exhibited the trend close to the Newtonian fluids. Moreover, PAN/DMSO/Si blending polymer solution with F127 exhibited the best dispersity and stability, indicating its best physical properties and machinability. 相似文献
5.
Golam Haider Krishna Sampathkumar Tim Verhagen Lukáš Nádvorník Farjana J. Sonia Václav Valeš Jan Sýkora Peter Kapusta Petr Němec Martin Hof Otakar Frank Yang-Fang Chen Jana Vejpravová Martin Kalbáč 《Advanced functional materials》2021,31(29):2102196
Recent advancements in isolation and stacking of layered van der Waals materials have created an unprecedented paradigm for demonstrating varieties of 2D quantum materials. Rationally designed van der Waals heterostructures composed of monolayer transition-metal dichalcogenides (TMDs) and few-layer hBN show several unique optoelectronic features driven by correlations. However, entangled superradiant excitonic species in such systems have not been observed before. In this report, it is demonstrated that strong suppression of phonon population at low temperature results in a formation of a coherent excitonic-dipoles ensemble in the heterostructure, and the collective oscillation of those dipoles stimulates a robust phase synchronized ultra-narrow band superradiant emission even at extremely low pumping intensity. Such emitters are in high demand for a multitude of applications, including fundamental research on many-body correlations and other state-of-the-art technologies. This timely demonstration paves the way for further exploration of ultralow-threshold quantum-emitting devices with unmatched design freedom and spectral tunability. 相似文献
6.
Fabiana D'Isanto Federico Smeacetto Hans-Peter Martin Richard Sedlák Maksym Lisnichuk Andreas Chrysanthou Milena Salvo 《Ceramics International》2021,47(14):19774-19783
A silica-based glass-ceramic, with Y2Ti2O7 as the major crystalline phase, is designed, characterised and tested as an oxidation-protective coating for a titanium suboxide (TiOx) thermoelectric material at temperatures of up to 600 °C. The optimised sinter-crystallisation treatment temperatures are found to be 1300 °C and 855 °C for a duration of 30 min, and this treatment leads to a glass-ceramic with cubic Y2Ti2O7 and CaAl2Si2O8 as crystalline phases. An increase of ~270 °C in the dilatometric softening temperature is observed after devitrification of the parent glass, thus further extending its working temperature range.Excellent adhesion of the glass-ceramic coating to the thermoelectric material is maintained after exposure to a temperature of 600 °C for 120 h under oxidising conditions, thus confirming the effectiveness of the T1 glass-ceramic in protecting the TiOx material. 相似文献
7.
8.
Wenlong Song Shoujun Wang Yang Lu Xuan Zhang Zixiang Xia Kai Sun Guangming Xin 《Ceramics International》2021,47(9):12631-12640
To enhance the tribological performance of Si3N4/TiC ceramics, MoS2/PTFE composite coatings were deposited on the ceramic substrate through spraying method. The micrographs and basic properties of the MoS2/PTFE coated samples were investigated. Dry sliding friction experiments against WC/Co ball were performed with the coated ceramics and traditional ones. These results showed that the composite coatings could significantly reduce the friction coefficient of ceramics, and protect the substrate from adhesion wear. The primary tribological mechanisms of the coated ceramics were abrasive wear, coating spalling and delamination, and the tribological property was transited from slight wear to serious wear with the increase of load because of the lower surface hardness and shear strength. The possible mechanisms for the effects of MoS2/PTFE composite coatings on the friction performance of ceramics were discussed. 相似文献
10.
Journal of Low Temperature Physics - This study modeled and investigated the magnetocaloric effect in Ni2MnGa Heusler alloy characterized by its magnetic entropy change (ΔSm) and its... 相似文献