全文获取类型
收费全文 | 74176篇 |
免费 | 8497篇 |
国内免费 | 5421篇 |
专业分类
电工技术 | 6475篇 |
技术理论 | 4篇 |
综合类 | 7854篇 |
化学工业 | 10060篇 |
金属工艺 | 4826篇 |
机械仪表 | 5253篇 |
建筑科学 | 5468篇 |
矿业工程 | 3284篇 |
能源动力 | 2237篇 |
轻工业 | 7187篇 |
水利工程 | 2191篇 |
石油天然气 | 3027篇 |
武器工业 | 1175篇 |
无线电 | 7787篇 |
一般工业技术 | 6611篇 |
冶金工业 | 2942篇 |
原子能技术 | 1176篇 |
自动化技术 | 10537篇 |
出版年
2024年 | 232篇 |
2023年 | 1305篇 |
2022年 | 2863篇 |
2021年 | 3705篇 |
2020年 | 2747篇 |
2019年 | 1917篇 |
2018年 | 2220篇 |
2017年 | 2417篇 |
2016年 | 2067篇 |
2015年 | 3239篇 |
2014年 | 4218篇 |
2013年 | 4959篇 |
2012年 | 6071篇 |
2011年 | 6158篇 |
2010年 | 5941篇 |
2009年 | 5504篇 |
2008年 | 5712篇 |
2007年 | 5351篇 |
2006年 | 4632篇 |
2005年 | 3798篇 |
2004年 | 2921篇 |
2003年 | 2181篇 |
2002年 | 2069篇 |
2001年 | 1887篇 |
2000年 | 1397篇 |
1999年 | 705篇 |
1998年 | 346篇 |
1997年 | 269篇 |
1996年 | 273篇 |
1995年 | 222篇 |
1994年 | 154篇 |
1993年 | 108篇 |
1992年 | 98篇 |
1991年 | 79篇 |
1990年 | 67篇 |
1989年 | 62篇 |
1988年 | 42篇 |
1987年 | 35篇 |
1986年 | 26篇 |
1985年 | 14篇 |
1984年 | 6篇 |
1983年 | 7篇 |
1982年 | 11篇 |
1981年 | 13篇 |
1980年 | 12篇 |
1979年 | 6篇 |
1966年 | 2篇 |
1965年 | 2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 15 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
4.
5.
深入浅出阐释智慧调峰泵站的基本组成与工作原理,论述有效调峰的基本内涵、实现方法及重要性,给出智慧调峰泵站的设计案例并指出其应用优势,就今后研究设计工作的重点内容给出建议。 相似文献
6.
Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) films are attracting famous applications in antistatic coating, energy storage and conversion, printed electronics, and biomedical fields due to their conductivity, optical transparency and flexibility. However, PEDOT:PSS has poor dispersion stability during long-term storage and transport. Moreover, the dried PEDOT:PSS films are insoluble in any solvent and cannot be redispersed again. In comparison to bake drying, here, a feasible strategy to achieve mechanically redispersed PEDOT:PSS with the help of freeze-drying process was reported. The redispersed PEDOT:PSS can recover not only the initial characters such as pH, chemical composition, viscosity, and particle size under similar solid contents, but also conductivity and surface morphology of treated films. In addition, the treated film exhibits self-healing properties similar to pristine film in terms of mechanical and electrical properties. This technology enables reuse and overcomes the technical problems of PEDOT:PSS dispersion, realizing real-time processing to meet variable applications. 相似文献
7.
Because of its ability to change optical absorption dynamically by applied electric field, nickel oxide (NiO) is a promising anodic material in smart windows, which can improve energy conversion efficiency in construction buildings. Although many works have achieved high electrochromic performance with different method. The underlying mechanism is still not fully investigated. In this article, we prepared the NiO films with large specific surface area and high stability by electron beam evaporation. X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were employed to figure out the surface morphology and composition of as-deposited films. Afterwards, the electrochemical properties and optical performance of the prepared NiO films were investigated. On this basis, the origin of surface charge was fully analyzed by cyclic voltammetry and diffusion coefficient test. These experimental and theoretical results firmly confirm that both the surface reaction and capacitive effect bring about the excellent EC performance in NiO films. These results not only provide clear evidence about electrochemical kinetics in NiO films, but also offer some useful guidelines for the design of EC materials with higher performance and longer stability. 相似文献
8.
针对伊拉克米桑油田盐膏层巨厚、钻井液密度窗口窄、存在高压盐水层,储层段漏塌同层导致复杂时效高等问题,通过对比分析国内外盐膏层和窄压力窗口地层钻井技术,总结了米桑油田钻井面临的主要技术难点,从井身结构优化、钻井提速和复杂预防等方面入手,研究形成了适合米桑油田的钻井关键技术,并进行了现场试验应用,取得了显著的效果.伊拉克米桑油田钻井关键技术对该地区钻井技术方案设计和钻井提速提效具有较强的借鉴和指导作用. 相似文献
9.
10.
为了有效预测输电网系统在强风作用下的响应,并开展高效精准的性能评估,文章提出了基于深度学习模型的风致易损性评估框架。以某具备健康监测系统的输电塔结构为例,首先对监测数据进行清洗和重构,通过大数据深度学习建立荷载输入和响应输出的等效映射模型,然后通过数值模拟生成灾害强度均匀的风场数据并由深度学习模型预测输电塔关键杆件响应,计算不同性能水准的易损性曲线。研究结果表明,经训练的深度学习模型可以涵盖实际工程中存在的各类不确定性因素,有效映射复杂风环境下输电塔结构的动力响应。提出的框架方法可以避免单纯通过数值模型制备大量动态响应数据,更高效地进行输电网系统风致易损性评估。 相似文献