全文获取类型
收费全文 | 4382篇 |
免费 | 431篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 45篇 |
综合类 | 6篇 |
化学工业 | 1144篇 |
金属工艺 | 118篇 |
机械仪表 | 231篇 |
建筑科学 | 77篇 |
矿业工程 | 1篇 |
能源动力 | 187篇 |
轻工业 | 321篇 |
水利工程 | 3篇 |
石油天然气 | 5篇 |
武器工业 | 2篇 |
无线电 | 800篇 |
一般工业技术 | 1073篇 |
冶金工业 | 309篇 |
原子能技术 | 60篇 |
自动化技术 | 438篇 |
出版年
2024年 | 4篇 |
2023年 | 42篇 |
2022年 | 59篇 |
2021年 | 88篇 |
2020年 | 98篇 |
2019年 | 136篇 |
2018年 | 151篇 |
2017年 | 138篇 |
2016年 | 200篇 |
2015年 | 162篇 |
2014年 | 217篇 |
2013年 | 304篇 |
2012年 | 283篇 |
2011年 | 370篇 |
2010年 | 278篇 |
2009年 | 285篇 |
2008年 | 260篇 |
2007年 | 181篇 |
2006年 | 162篇 |
2005年 | 146篇 |
2004年 | 127篇 |
2003年 | 129篇 |
2002年 | 109篇 |
2001年 | 89篇 |
2000年 | 84篇 |
1999年 | 93篇 |
1998年 | 122篇 |
1997年 | 103篇 |
1996年 | 83篇 |
1995年 | 55篇 |
1994年 | 26篇 |
1993年 | 41篇 |
1992年 | 22篇 |
1991年 | 26篇 |
1990年 | 26篇 |
1989年 | 15篇 |
1988年 | 15篇 |
1987年 | 8篇 |
1986年 | 5篇 |
1985年 | 7篇 |
1984年 | 5篇 |
1983年 | 7篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1976年 | 10篇 |
1975年 | 7篇 |
1973年 | 4篇 |
1967年 | 5篇 |
排序方式: 共有4820条查询结果,搜索用时 15 毫秒
991.
Sehyun Lee Jae Young Jung Injoon Jang Daeil Choi Myeong Jae Lee Dong Wook Lee Jue-Hyuk Jang Jeong Hee Lee Haneul Jin Kyungmin Im Eungjun Lee Seung-hoon Kim Nam Dong Kim Soo-Hyoung Lee Yun Sik Kang Hee-Young Park Dongwon Chun Hyung Chul Ham Kug-Seung Lee Docheon Ahn Pil Kim Sung Jong Yoo 《Advanced functional materials》2021,31(16):2009241
Among the Pt group metals, Pd has been considered the most efficient for application in electrocatalysts as an alternative to Pt. Despite the comparable electrochemical activities of Pd and Pd-metal alloys, they are vulnerable to liquid acidic electrolytes, leading to degradation of catalytic activity. Pd–Ni alloys have been used to enhance catalytic activity because the electronic structure of Pd can be easily changed by adding Ni. In other studies, N atoms have been introduced for more stable M–Ni catalysts by inducing the formation of Ni4N species; however, the structural analysis and the role of nitrogen have not been fully understood yet. Herein, the Pd–Ni alloy nitride with a unique crystal structure shows a promising catalytic activity for oxygen reduction reaction (ORR). The nitride PdNi nanoparticles have a novel monolithic antiperovskite structure of chemical formula (PdxNi1−x)NNi3. The unique antiperovskite crystal (PdxNi1−x)NNi3 possesses superior ORR activity and stability, originating from the downshifted d-band center of the monolayer Pd/antiperovskite surface and the lower formation energy of the antiperovskite core nanocrystal. Consequently, (PdxNi1−x)NNi3, as a Pt-free Pd-based electrocatalyst, overcomes the stability issue of Pd under acidic conditions by achieving 99-times higher mass activity than commercial Pd/C, as shown by the durability test. 相似文献
992.
Trinh Thi Ly Jungmin Park Kyoo Kim Hyo-Bin Ahn Nyun Jong Lee Kwangsu Kim Tae-Eon Park Ganbat Duvjir Nguyen Huu Lam Kyuha Jang Chun-Yeol You Younghun Jo Se Kwon Kim Changgu Lee Sanghoon Kim Jungdae Kim 《Advanced functional materials》2021,31(17):2009758
Microscopic structures and magnetic properties are investigated for Fe5−xGeTe2 single crystal, recently discovered as a promising van der Waals (vdW) ferromagnet. An Fe atom (Fe(1)) located in the outermost Fe5Ge sublayer has two possible split-sites which are either above or below the Ge atom. Scanning tunneling microscopy shows √3 × √3 superstructures which are attributed to the ordering of Fe(1) layer. The √3 × √3 superstructures have two different phases due to the symmetry of Fe(1) ordering. Intriguingly, the observed √3 × √3 ordering breaks the inversion symmetry of crystal, resulting in substantial antisymmetric exchange interaction. The temperature dependence of magnetization reveals a sharp magnetic anomaly suggesting helical magnetism of the Fe5−xGeTe2 due to its non-centrosymmetricity. Analytical study also supports that the observed ordering can give rise to the helimagnetism. The work will provide essential information to understand the complex magnetic properties and the origin of the new vdW ferromagnet, Fe5−xGeTe2 for future topology-based spin devices. 相似文献
993.
Licong Peng Fehmi S. Yasin Tae-Eon Park Sung Jong Kim Xichao Zhang Takuro Nagai Koji Kimoto Seonghoon Woo Xiuzhen Yu 《Advanced functional materials》2021,31(37):2103583
The advent of ferromagnetism in 2D van der Waals (vdW) magnets has stimulated high interest in exploring topological magnetic textures, such as skyrmions for use in future skyrmion-based spintronic devices. To engineer skyrmions in vdW magnets by transforming Bloch-type magnetic bubbles into Néel-type skyrmions, a heavy metal/vdW magnetic thin film heterostructure has been made to induce interfacial Dzyaloshinskii–Moriya interaction (DMI). However, the unambiguous identification of the magnetic textures inherent to vdW magnets, for example, whether the magnetic twists (skyrmions/domain walls) are Néel- or Bloch-type, is unclear. Here we demonstrate that the magnetic twists can be tuned between Néel and Bloch-type in the vdW magnet Fe3GeTe2 (FGT) with/without interfacial DMI. We use an in-plane magnetic field to align the modulation wavevector q of the magnetizations in order to distinguish the Néel- or Bloch-type magnetic twists. We observe that q is perpendicular to the in-plane field in the heterostructure (Pt/oxidized-FGT/FGT/oxidized-FGT), while q aligns at a rotated angle with respect to the field direction in the FGT thin plate thinned from bulk. We find that the aligned domain wall twists hold fan-like modulations, coinciding qualitatively with our computational results. 相似文献
994.
Wei Peng Jacob A. Zorn Junsik Mun Muhammad Sheeraz Chang Jae Roh Jun Pan Bo Wang Kun Guo Chang Won Ahn Yaping Zhang Kui Yao Jong Seok Lee Jin‐Seok Chung Tae Heon Kim Long‐Qing Chen Miyoung Kim Lingfei Wang Tae Won Noh 《Advanced functional materials》2020,30(16)
Ferroelectric materials owning a polymorphic nanodomain structure usually exhibit colossal susceptibilities to external mechanical, electrical, and thermal stimuli, thus holding huge potential for relevant applications. Despite the success of traditional strategies by means of complex composition design, alternative simple methods such as strain engineering have been intensively sought to achieve a polymorphic nanodomain state in lead‐free, simple‐composition ferroelectric oxides in recent years. Here, a nanodomain configuration with morphed structural phases is realized in an epitaxial BaTiO3 film grown on a (111)‐oriented SrTiO3 substrate. Using a combination of experimental and theoretical approaches, it is revealed that a threefold rotational symmetry element enforced by the epitaxial constraint along the [111] direction of BaTiO3 introduces considerable instability among intrinsic tetragonal, orthorhombic, and rhombohedral phases. Such phase degeneracy induces ultrafine ferroelectric nanodomains (1–10 nm) with low‐angle domain walls, which exhibit significantly enhanced dielectric and piezoelectric responses compared to the (001)‐oriented BaTiO3 film with uniaxial ferroelectricity. Therefore, the finding highlights the important role of epitaxial symmetry in domain engineering of oxide ferroelectrics and facilitates the development of dielectric capacitors and piezoelectric devices. 相似文献
995.
Byoung Soo Kim Hyowon Kwon Hyun Jeong Kwon Jun Beom Pyo Jinwoo Oh Soo Yeong Hong Jong Hyuk Park Kookheon Char Jeong Sook Ha Jeong Gon Son Sang‐Soo Lee 《Advanced functional materials》2020,30(21)
A commonly used strategy to impose deformability on conductive materials is the prestrain method, in which conductive materials are placed on prestretched elastic substrates and relaxed to create wavy or wrinkled structures. However, 1D metallic nanowire (NW) networks typically result in out‐of‐plane buckling defects and NW fractures, due to their rigid and brittle nature and nonuniform load transfer to specific points of NW. To resolve these problems, an alternative method is proposed to control the elastic modulus of 1D NW networks through contact with various solvents during compressive strain. Through solvent contact, the interface interactions between the NWs and between the NW and substrate can be controlled, and it is shown that the surface instability of the 1D random network is formed differently from a uniform bilayer film, which also can vary with the modulus of the network. For modulus values lower than the critical point, slippage and rearrangement of NW strands mainly occur and individual strands in the network show an in‐plane wavy configuration, which is ideal for structural stretchability. Based on the solvent‐assisted prestrain method, letter‐sized, large‐area stretchable, and transparent electrodes with high transparency and conductivity are achieved, and stretchable and transparent alternating current electroluminescent devices for stretchable display applications are also realized. 相似文献
996.
Heterostructured catalysts are hybrid materials that contain interfaces between their constituents formed through combinations of multiple solid‐state materials. The presence of multiple constituents institutes a synergistic effect that endows the catalyst with superior performance and appreciable potential in a diverse range of catalytic applications, including electrocatalytic and photocatalytic reduction of carbon dioxide. These promising catalysts can support a feasible method for large‐scale processing of valuable carbonaceous feedstock or fuel generation and alleviation of atmospheric carbon dioxide levels. Such technologies will serve as the much‐needed remedy for the global energy and environmental crisis. A broad spectrum of recently developed heterostructured catalysts pertaining to electrocatalytic and photocatalytic carbon dioxide reduction is evaluated. The insights included are of relevance to refresh fundamentals pertaining to the electron transfer processes leading to carbon dioxide reduction and the mechanistic reduction pathways yielding a possible multitude of carbonaceous products. Detailed discussions provide a rational understanding of how the hybrid and resultant properties from various combinations are useful in enhancing catalytic function. Lastly, the performance profiles of various catalyst structures together with modification strategies employed are of interest to highlight the current challenges to and directions for future catalyst development. 相似文献
997.
Bo Hou Byung‐Sung Kim Harrison Ka Hin Lee Yuljae Cho Paul Giraud Mengxia Liu Jingchao Zhang Matthew L. Davies James R. Durrant Wing Chung Tsoi Zhe Li Stoichko D. Dimitrov Jung Inn Sohn SeungNam Cha Jong Min Kim 《Advanced functional materials》2020,30(39)
Colloidal metal chalcogenide quantum dots (QDs) have excellent quantum efficiency in light–matter interactions and good device stability. However, QDs have been brought to the forefront as viable building blocks in bottom‐up assembling semiconductor devices, the development of QD solar cell (QDSC) is still confronting considerable challenges compared to other QD technologies due to their low performance under natural sunlight, as a consequence of untapped potential from their quantized density‐of‐state and inorganic natures. This report is designed to address this long‐standing challenge by accessing the feasibility of using QDSC for indoor and concentration PV (CPV) applications. This work finds that above bandgap photon energy irradiation of QD solids can generate high densities of excitons via multi‐photon absorption (MPA), and these excitons are not limited to diffuse by Auger recombination up to 1.5 × 1019 cm?3 densities. Based on these findings, a 19.5% (2000 lux indoor light) and an 11.6% efficiency (1.5 Suns) have been facilely realized from ordinary QDSCs (9.55% under 1 Sun). To further illustrate the potential of the MPA in QDSCs, 21.29% efficiency polymer lens CPVs (4.08 Suns) and viable sensor networks powered by indoor QDSCs matrix have been demonstrated. 相似文献
998.
Ryu Jung Hyun Sharma Pradip Kumar Jo Jeong Hoon Park Jong Hyuk 《The Journal of supercomputing》2019,75(8):4372-4387
The Journal of Supercomputing - Until now, there has been little research on digital forensics in the IoT (Internet of Things)-based infrastructure. Current digital forensic tools, investigation... 相似文献
999.
In this work, a recycling method for phenol resin (Bakelite) waste using supercritical methanol was investigated. Phenol resin is manufactured by the condensation reaction between phenol and formaldehyde to form insoluble and infusible three-dimensional reticulate structures. For this reason, these resins are mostly buried or incinerated as waste, and only a small percentage is reused as filler materials. In terms of reducing environmental pollution and improving waste management, the development of recycling technologies for phenol resin waste is necessary. In this study, phenol resin waste was treated with supercritical methanol over the 553.15–703.15 K temperature range and at pressures up to 20.6 MPa. As a result of this treatment, waste was decomposed into phenol and carbon particles. Carbon particles began from at temperatures and pressures above 603.15 K and 13.9 MPa, respectively. The sizes of the carbon particles obtained in this manner ranged from 1 to \(4~\upmu \hbox {m}\) and decreased with increasing temperature and pressure. These carbon particles had identical chemical and crystal structures and crystallinities to amorphous carbon. This recycled carbon can be used for the same purposes as existing amorphous carbon. 相似文献
1000.
Electrocatalysis: Porous Cobalt Phosphide Polyhedrons with Iron Doping as an Efficient Bifunctional Electrocatalyst (Small 40/2017) 下载免费PDF全文