全文获取类型
收费全文 | 112639篇 |
免费 | 11073篇 |
国内免费 | 6956篇 |
专业分类
电工技术 | 8032篇 |
技术理论 | 10篇 |
综合类 | 9582篇 |
化学工业 | 16786篇 |
金属工艺 | 6880篇 |
机械仪表 | 7087篇 |
建筑科学 | 8823篇 |
矿业工程 | 3845篇 |
能源动力 | 3099篇 |
轻工业 | 10496篇 |
水利工程 | 2935篇 |
石油天然气 | 4990篇 |
武器工业 | 1305篇 |
无线电 | 12389篇 |
一般工业技术 | 12186篇 |
冶金工业 | 5000篇 |
原子能技术 | 1680篇 |
自动化技术 | 15543篇 |
出版年
2024年 | 442篇 |
2023年 | 1895篇 |
2022年 | 3866篇 |
2021年 | 5226篇 |
2020年 | 3823篇 |
2019年 | 2961篇 |
2018年 | 3220篇 |
2017年 | 3517篇 |
2016年 | 3263篇 |
2015年 | 4715篇 |
2014年 | 5816篇 |
2013年 | 7069篇 |
2012年 | 8297篇 |
2011年 | 8636篇 |
2010年 | 7480篇 |
2009年 | 7286篇 |
2008年 | 7356篇 |
2007年 | 6943篇 |
2006年 | 6302篇 |
2005年 | 5336篇 |
2004年 | 4008篇 |
2003年 | 3085篇 |
2002年 | 2804篇 |
2001年 | 2449篇 |
2000年 | 2435篇 |
1999年 | 2287篇 |
1998年 | 1773篇 |
1997年 | 1439篇 |
1996年 | 1419篇 |
1995年 | 1173篇 |
1994年 | 1021篇 |
1993年 | 724篇 |
1992年 | 566篇 |
1991年 | 405篇 |
1990年 | 357篇 |
1989年 | 321篇 |
1988年 | 236篇 |
1987年 | 162篇 |
1986年 | 117篇 |
1985年 | 85篇 |
1984年 | 57篇 |
1983年 | 44篇 |
1982年 | 49篇 |
1981年 | 34篇 |
1980年 | 44篇 |
1979年 | 20篇 |
1976年 | 13篇 |
1974年 | 11篇 |
1959年 | 12篇 |
1951年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 31 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
3.
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
4.
飞机从一个航段飞向下一个航段时,需要对下个航段是否激活进行判断.提出了一种新的飞行计划航段自动激活方法,通过获取飞机当前位置及其磁差,并结合临近的3个航路点对应位置的磁差经纬度,分别计算3个航路点与飞机位置对应的磁航向角,通过磁航向角之间做差进行比较,进而判断是否被激活.算法推导完成后,通过基于模型的系统工程工具SCADE SUITE进行了建模,并结合杰普逊航图进行了实际数据采样与仿真.仿真结果表明:该航段自动激活方法能够有效稳定地激活下一航段,比传统方法计算简便,方法实用有效.已在实际飞行中成功应用,达到了预期效果. 相似文献
5.
6.
针对赤泥等固体废弃物对环境危害性大且利用率低等问题,以碱激发赤泥-矿渣基地聚物注浆材料为
研究对象,研究了不同掺量的聚羧酸(PA)减水剂、醛酮缩合物(AKC)减水剂和萘系(N)减水剂对材料凝结时间、流动
性及强度等的影响,并通过 XRD、傅里叶红外光谱及 SEM 等设备对减水剂的作用机理进行研究。 结果表明:减水剂增
强了材料的流动性但降低了材料的剪切应力;N 和 PA 减水剂能缩短材料的凝结时间,但 AKC 减水剂会延长材料的凝
结时间;N 和 AKC 减水剂能提高材料的强度,但 PA 减水剂会降低材料的强度;N 减水剂对材料的综合性能提升效果
更加明显,其最优掺量为 0. 7%;减水剂对赤泥-矿渣基地聚物性能提升的作用机理主要是促进地聚合物凝胶的形成。
研究成果为拓展赤泥在工程上的使用途径和效率提供了理论指导。 相似文献
7.
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
9.
Liang Yan-Jun Lu You-Jun Gao De-Xin Wang Zhong-Sheng 《International Journal of Control, Automation and Systems》2022,20(2):507-514
International Journal of Control, Automation and Systems - The vibration control problem of offshore jacket platforms is studied. The model of offshore platforms with nonlinear interactions of the... 相似文献
10.