全文获取类型
收费全文 | 1095篇 |
免费 | 231篇 |
国内免费 | 78篇 |
专业分类
电工技术 | 92篇 |
综合类 | 70篇 |
化学工业 | 180篇 |
金属工艺 | 45篇 |
机械仪表 | 70篇 |
建筑科学 | 121篇 |
矿业工程 | 34篇 |
能源动力 | 28篇 |
轻工业 | 165篇 |
水利工程 | 40篇 |
石油天然气 | 59篇 |
武器工业 | 15篇 |
无线电 | 141篇 |
一般工业技术 | 139篇 |
冶金工业 | 27篇 |
原子能技术 | 23篇 |
自动化技术 | 155篇 |
出版年
2024年 | 34篇 |
2023年 | 99篇 |
2022年 | 146篇 |
2021年 | 157篇 |
2020年 | 77篇 |
2019年 | 49篇 |
2018年 | 71篇 |
2017年 | 63篇 |
2016年 | 43篇 |
2015年 | 46篇 |
2014年 | 53篇 |
2013年 | 48篇 |
2012年 | 56篇 |
2011年 | 51篇 |
2010年 | 39篇 |
2009年 | 33篇 |
2008年 | 39篇 |
2007年 | 35篇 |
2006年 | 32篇 |
2005年 | 20篇 |
2004年 | 23篇 |
2003年 | 26篇 |
2002年 | 9篇 |
2001年 | 21篇 |
2000年 | 17篇 |
1999年 | 25篇 |
1998年 | 15篇 |
1997年 | 11篇 |
1996年 | 17篇 |
1995年 | 9篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 9篇 |
1991年 | 9篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1979年 | 1篇 |
1951年 | 2篇 |
排序方式: 共有1404条查询结果,搜索用时 15 毫秒
991.
992.
993.
网络并行计算的编程要求设计者对任务的分解、分配及子任务间的交互等问题有更高的技术。论文给出了在网络并行计算的一种新平台,用户只需提交数据和对它的操作即可。 相似文献
994.
995.
Yang Huang Xinyi Li Xiao Xu Feng Wei Ying Wang Mengtao Ma Yu Wang Dongping Sun 《Advanced Powder Technology》2021,32(7):2484-2492
An extremely facile and up-scalable approach has been proposed to disperse ferric grains onto bacterial cellulose (BC) nanofibers. The BC-induced hydrolytic deposition can be performed at room temperature without using any organic solvents, toxic reagents, or complicated apparatuses, enabling a green pathway in realizing industrialization. After carbonization, the randomly oriented carbonized BC (CBC) nanofibers transmit the electrons throughout the electrode, while the inherited reticular morphology boosts the thorough penetration of electrolyte. Moreover, the sufficient space created by interconnected CBC nanofibers is able to accommodate the volume change of the nanosized Fe3O4 active materials during repeated Li+ intercalation and deintercalation. As a result, the as-prepared Fe3O4/CBC composites deliver the superior electrochemical performance as the free-standing anodes in Li-ion batteries (LIBs), including the impressive reversible capacity of 702 mAh g?1 after 400 cycles at 400 mA g?1, decent rate capability with capacity of 437 mAh g?1 at 2000 mA g?1, and a long cycling lifespan up to 1000 cycles at 800 mA g?1. This work provides a scalable and green approach to fabricate high-performance LIBs anode with the natural sustainable biomass. 相似文献
996.
Xinyi Liu Yuxiang Ding Bingjie Zhao Yuanyuan Liu Shilin Luo Junyong Wu 《Drug development and industrial pharmacy》2016,42(12):2031-2037
Puerarin, which is extracted from Chinese medicine, is widely used in China and mainly used as a therapeutic agent for the treatment of cardiovascular diseases. Owing to its short elimination half-life in human beings, frequently intravenous administration of high doses of puerarin may be needed, which possibly leads to severe and acute side effects. The development of an effective sustained-release drug delivery system is urgently needed. In this study, PEGylated mesoporous silica nanoparticles (PEG-MSNs) had become a preferred way to prolong the half-life and improve the bioavailability of drugs. The release of puerarin from PEG-MSNs was pH dependent, and the release rate was much faster at lower pH than that at higher pH. Moreover, the PEG-MSNs exhibited improved blood compatibility over the MSNs in terms of low hemolysis, and it could also reduce the side effect of hemolysis induced by PUE. Compared with puerarin, PUE-loaded PEG-MSNs showed a 2.3-fold increase in half-life of puerarin and a 1.47-fold increase in bioavailability. Thus, the PEG-MSNs hold the substantial potential to be further developed as an effective sustained-release drug delivery system. 相似文献
997.
Xinyi Wang Xiaofeng Wang Mingzhe Wang Di Zhang Qi Yang Tao Liu Rong Lei Shuifang Zhu Yuliang Zhao Chunying Chen 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(16)
Chiral properties of nanoscale materials are of importance as they dominate interactions with proteins in physiological environments; however, they have rarely been investigated. In this study, a systematic investigation is conducted for the adsorption behaviors of bovine serum albumin (BSA) onto the chiral surfaces of gold nanoparticles (AuNPs), involving multiple techniques and molecular dynamic (MD) simulation. The adsorption of BSA onto both L‐ and D‐chiral surfaces of AuNPs shows discernible differences involving thermodynamics, adsorption orientation, exposed charges, and affinity. As a powerful supplement, MD simulation provides a molecular‐level understanding of protein adsorption onto nanochiral surfaces. Salt bridge interaction is proposed as a major driving force at protein–nanochiral interface interaction. The spatial distribution features of functional groups (? COO?, ? NH3+, and ? CH3) of chiral molecules on the nanosurface play a key role in the formation and location of salt bridges, which determine the BSA adsorption orientation and binding strength to chiral surfaces. Sequentially, BSA corona coated on nanochiral surfaces affects their uptake by cells. The results enhance the understanding of protein corona, which are important for biological effects of nanochirality in living organisms. 相似文献
998.
Yu Wang Mengzhu Qiao Guangqing Xu Zhixiang Zheng Xinyi Zhang 《Fullerenes, Nanotubes and Carbon Nanostructures》2018,26(4):210-217
A visible-light-driven g-C3N4/g-C3N4 isotype heterojunction photocatalyst was synthesized by one-step thermal treatment using urea and thiourea as the precursor. The photocatalytic activity of as-prepared photocatalyst was evaluated through the degradation of rhodamine B (RhB) and tetracycline hydrochloride (TC) under the visible light irradiation. The hybrid showed enhanced photocatalytic activity in photodegradating the applied pollutants as compared with single g-C3N4. When the ratio of urea to thiourea was 2:1, the prepared isotype heterojunction exhibited the highest photocatalytic activity and the photodegradation rates for RhB and TC were 99.8% and 95.1% after being visible light irradiated for 1 h and 4 h respectively. The enhanced photocatalytic performance of the isotype heterojunction is ascribed to the enhanced charge separation efficiency. After being reused for 5 times, the hybrid still showed excellent recyclability and chemical stability. Furthermore, NaI, BQ and IPA were used as the sacrificial agents for studying the surface reactions in the photocatalytic process. The method used in this work provides a new pathway to achieve more efficient degradation of antibiotics and to stimulate further studies in this important field. 相似文献
999.
Ruirui Liu Jian Zhao Qian Han Xinyi Hu Dong Wang Xu Zhang Peng Yang 《Advanced materials (Deerfield Beach, Fla.)》2018,30(38)
Advances in material design and applications are highly dependent on the development of particle surface engineering strategies. However, few universal methods can functionalize particles of different compositions, sizes, shapes, and structures. The amyloid‐like lysozyme assembly‐mediated surface functionalization of inorganic, polymeric or metal micro/nanoparticles in a unique amyloid‐like phase‐transition buffer containing lysozyme are described. The rapid formation of a robust nanoscale phase‐transitioned lysozyme (PTL) coating on the particle surfaces presents strong interfacial binding to resist mechanical and chemical peeling under harsh conditions and versatile surface functional groups to support various sequential surface chemical derivatizations, such as radical living graft polymerization, the electroless deposition of metals, biomineralization, and the facile synthesis of Janus particles and metal/protein capsules. Being distinct from other methods, the preparation of this pure protein coating under biocompatible conditions (e.g., neutral pH and nontoxic reagents) provides a reliable opportunity to directly modify living cell surfaces without affecting their biological activity. The PTL coating arms yeasts with a functional shell to protect their adhered body against foreign enzymatic digestion. The PTL coating further supports the surface immobilization of living yeasts for heterogeneous microbial reactions and the sequential surface chemical derivatization of the cell surfaces, e.g., radical living graft polymerization. 相似文献
1000.
Facilitated Oxygen Chemisorption in Heteroatom‐Doped Carbon for Improved Oxygen Reaction Activity in All‐Solid‐State Zinc–Air Batteries 下载免费PDF全文
Sisi Liu Mengfan Wang Xinyi Sun Na Xu Jie Liu Yuzhou Wang Tao Qian Chenglin Yan 《Advanced materials (Deerfield Beach, Fla.)》2018,30(4)
Driven by the intensified demand for energy storage systems with high‐power density and safety, all‐solid‐state zinc–air batteries have drawn extensive attention. However, the electrocatalyst active sites and the underlying mechanisms occurring in zinc–air batteries remain confusing due to the lack of in situ analytical techniques. In this work, the in situ observations, including X‐ray diffraction and Raman spectroscopy, of a heteroatom‐doped carbon air cathode are reported, in which the chemisorption of oxygen molecules and oxygen‐containing intermediates on the carbon material can be facilitated by the electron deficiency caused by heteroatom doping, thus improving the oxygen reaction activity for zinc–air batteries. As expected, solid‐state zinc–air batteries equipped with such air cathodes exhibit superior reversibility and durability. This work thus provides a profound understanding of the reaction principles of heteroatom‐doped carbon materials in zinc–air batteries. 相似文献