全文获取类型
收费全文 | 4417篇 |
免费 | 378篇 |
国内免费 | 196篇 |
专业分类
电工技术 | 237篇 |
技术理论 | 3篇 |
综合类 | 362篇 |
化学工业 | 809篇 |
金属工艺 | 154篇 |
机械仪表 | 217篇 |
建筑科学 | 418篇 |
矿业工程 | 98篇 |
能源动力 | 81篇 |
轻工业 | 358篇 |
水利工程 | 89篇 |
石油天然气 | 208篇 |
武器工业 | 24篇 |
无线电 | 548篇 |
一般工业技术 | 452篇 |
冶金工业 | 201篇 |
原子能技术 | 20篇 |
自动化技术 | 712篇 |
出版年
2024年 | 11篇 |
2023年 | 56篇 |
2022年 | 134篇 |
2021年 | 118篇 |
2020年 | 109篇 |
2019年 | 95篇 |
2018年 | 116篇 |
2017年 | 158篇 |
2016年 | 146篇 |
2015年 | 177篇 |
2014年 | 184篇 |
2013年 | 279篇 |
2012年 | 294篇 |
2011年 | 308篇 |
2010年 | 270篇 |
2009年 | 251篇 |
2008年 | 263篇 |
2007年 | 254篇 |
2006年 | 278篇 |
2005年 | 235篇 |
2004年 | 143篇 |
2003年 | 127篇 |
2002年 | 129篇 |
2001年 | 85篇 |
2000年 | 101篇 |
1999年 | 128篇 |
1998年 | 108篇 |
1997年 | 88篇 |
1996年 | 70篇 |
1995年 | 41篇 |
1994年 | 46篇 |
1993年 | 35篇 |
1992年 | 21篇 |
1991年 | 27篇 |
1990年 | 16篇 |
1989年 | 19篇 |
1988年 | 20篇 |
1987年 | 11篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1975年 | 1篇 |
排序方式: 共有4991条查询结果,搜索用时 15 毫秒
1.
Zhen Hong Mingshan Xue Yidan Luo Zuozhu Yin Chan Xie Junfei Ou Fajun Wang 《应用聚合物科学杂志》2021,138(2):49657
With the continuous development of bionics, such as, geckos and virginia creeper with both superhydrophobic and super-adhesive, the surface wetting and super-adhesive properties of various porous materials have attracted extensive attention of the scientific and medical communities. Here, the honeycomb polyurethane (PU) porous films with strong adhesion were successfully prepared by microphase separation method and the effects of growth parameters on their microstructure and adhesive strength to ice were investigated. It was found that a high relative humidity (e.g., 100%) and a low solution concentration (e.g., 2%) facilitated the formation of ordered honeycomb PU porous films, and as-prepared PU pores with average pore diameter as small as 5 μm are better ordered and more uniform than these in related documents. Although the contact angle of water droplets on the surface of PU porous films increased from the premodification value of 85–130° to more than 160° after surface modification with polydopamine (PDA), the corresponding rolling angle remained approximately constant (180°), indicating that the surface of PU porous films has strong adhesion similar to geckos and virginia creeper. Furthermore, at lower temperature, the PU porous films exhibited the high adhesive strength of 142.13 kPa on ice, which was strongly dependent on the porous microstructures and surface compositions. The improved adhesive behavior to ice of honeycomb PU porous films modified with PDA provides new strategies for surface modification of materials and potential applications in medical domain. 相似文献
2.
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
3.
4.
5.
在介绍PC键码特征的基础上,可利用AT89C2051来实现PC键盘的硬件设计.它具有结构简单、选择性强、便于实现等优点,特别适用于36个以下PC键盘的应用. 相似文献
6.
文章从发展水利经济的必要性入手,列举发展水利经济中存在的种种问题,提出发展水利经济可以采取相关的政策措施、工程措施和管理措施。 相似文献
7.
On effective offloading services for resource-constrained mobile devices running heavier mobile internet applications 总被引:1,自引:0,他引:1
Kun Yang Shumao Ou Hsiao-Hwa Chen 《Communications Magazine, IEEE》2008,46(1):56-63
Rapid advances in wireless mobile network technologies and mobile handsets (MHs) facilitate ubiquitous infrastructure that can support a range of mobile services and applications in addition to conventional mobile Internet access. One recent trend is to effectively run desktop PC-oriented heavier applications on MHs. However, due to their miniature, portable size, MHs are resource-constrained and therefore, running these applications directly on an MH is not satisfactory given a user's expectations. To cope with this problem, this article proposes a novel offloading service that can seamlessly offload some of the tasks of a mobile application from an MH to nearby, resource-rich PCs (called surrogates). The system architecture and key components of the proposed offloading service are presented, prototyped, and evaluated. The results of experiments and simulations have demonstrated the effectiveness and efficiency of this offloading service for mobile applications. 相似文献
8.
NetLinx技术的发展,使得跟踪系统发生了划时代的飞跃,在制造业上的应用更加广泛。本文以一间显像管厂为例,详细介绍了跟踪系统在制造业上的应用。 相似文献
9.
Thirty patients with mild to moderate essential hypertension had received four weeks treatment with Lacidipine and serum lipid peroxide (LPO), superoxide dismutase (SOD) and insulin levels were measured before and after treatment. The results showed: (1) there were decreased in SOD activity and increased Lpo content the patients group (P < 0.01); (2) after treated with Lacidipine, the SOD acitvity increased and Lpo content decreased (P < 0.01); (3) Lacidipine had obvious antihypertensive effect with no significant changes in heart rate; (4) Lacidipine had no significant effects on insulin, blood glucose and lipids. The results suggest that lacidipine is a safe and effective antihypertensive agent and can improve the metabolic balances in free radical system. 相似文献
10.
碱解玉米皮制备阿魏酸的研究 总被引:2,自引:0,他引:2
通过碱解玉米皮可释放阿魏酸.采用正交设计探讨了碱解和纯化阿魏酸的工艺,其最佳工艺为用含1%Na0H的50%乙醇溶液于85℃回流反应2h提取玉米皮(质量比110)中的阿魏酸.为防止阿魏酸氧化,在提取液中添加50 mg/100 mL的亚硫酸氢钠.将碱解液减压浓缩,用盐酸调节pH至3.0.每次用2倍体积的乙酸乙酯萃取3次,取酯相,减压挥干乙酸乙酯,用碱液溶解,再用盐酸调pH=2,所得产品为黄色油状物.检测结果表明,采用该工艺获得的阿魏酸纯度达82.69%,收率为148.92 mg/10 g玉米皮. 相似文献