全文获取类型
收费全文 | 28379篇 |
免费 | 2191篇 |
国内免费 | 863篇 |
专业分类
电工技术 | 1367篇 |
技术理论 | 1篇 |
综合类 | 1379篇 |
化学工业 | 5287篇 |
金属工艺 | 1454篇 |
机械仪表 | 1414篇 |
建筑科学 | 1937篇 |
矿业工程 | 597篇 |
能源动力 | 1041篇 |
轻工业 | 2345篇 |
水利工程 | 353篇 |
石油天然气 | 1352篇 |
武器工业 | 118篇 |
无线电 | 3263篇 |
一般工业技术 | 3881篇 |
冶金工业 | 1499篇 |
原子能技术 | 322篇 |
自动化技术 | 3823篇 |
出版年
2024年 | 91篇 |
2023年 | 438篇 |
2022年 | 725篇 |
2021年 | 1151篇 |
2020年 | 835篇 |
2019年 | 815篇 |
2018年 | 912篇 |
2017年 | 1011篇 |
2016年 | 993篇 |
2015年 | 1113篇 |
2014年 | 1487篇 |
2013年 | 1997篇 |
2012年 | 1797篇 |
2011年 | 1877篇 |
2010年 | 1545篇 |
2009年 | 1613篇 |
2008年 | 1465篇 |
2007年 | 1340篇 |
2006年 | 1413篇 |
2005年 | 1197篇 |
2004年 | 884篇 |
2003年 | 801篇 |
2002年 | 795篇 |
2001年 | 554篇 |
2000年 | 547篇 |
1999年 | 613篇 |
1998年 | 589篇 |
1997年 | 471篇 |
1996年 | 453篇 |
1995年 | 355篇 |
1994年 | 290篇 |
1993年 | 198篇 |
1992年 | 182篇 |
1991年 | 122篇 |
1990年 | 107篇 |
1989年 | 76篇 |
1988年 | 95篇 |
1987年 | 56篇 |
1986年 | 52篇 |
1985年 | 43篇 |
1984年 | 60篇 |
1983年 | 50篇 |
1982年 | 45篇 |
1981年 | 32篇 |
1980年 | 29篇 |
1979年 | 31篇 |
1977年 | 12篇 |
1976年 | 17篇 |
1975年 | 11篇 |
1973年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
Systematic errors in phase-measuring profilometry that are introduced by the modulation transfer function of a digital image-acquisition device are analyzed. New phase expressions and phase-deviation formulas are given. The results for simulations and experiments demonstrate that the algorithm of phase-measuring profilometry cannot be regarded as a point-to-point operation. To obtain precise results, an optimum scheme for setting the measurement system is also proposed. 相似文献
42.
Run Wang Hengyang Xiang Yan Li Yihui Zhou Qingsong Shan Yuqin Su Zhi Li Yongjin Wang Haibo Zeng 《Advanced functional materials》2023,33(21):2215189
Perovskite light-emitting diodes (PeLEDs) show promising prospects in the wide color gamut display owing to their ultra-narrow full width at half maximum (FWHM). However, up to now, all perovskite white LEDs integrated by standard red, green, and blue perovskite emitters, namely, monolithic white PeLEDs (WPeLEDs), have been rarely reported, owing to facing some issues, e.g., solvent incompatibility in solution technique, ion exchange, and energy transfer between different emission centers. Herein, centered on these issues, an optimal intermediate connection layer (ICL) of Po-T2T/LiF/Ag/HAT-CN/MoO3 is adopted to successfully develop monolithic tandem multicolor PeLEDs and WPeLEDs for the first time. The multicolor PeLEDs can achieve the best external quantum efficiency of 1.8% and the highest luminance of 4844 cd m−2. Besides, the red/green/blue (R/G/B) monolithic tandem WPeLED shows a standard white International Commission on Illumination coordinate of (0.33, 0.33) and achieves an extremely wide color gamut reaching National Television Standards Committee of 130%. This study is the first to realize the standard R/G/B co-electroluminescence in a monolithic perovskite device and offers a feasible strategy for developing wide-color gamut perovskite displays. 相似文献
43.
Computational Visual Media - In this paper, we tackle the challenging problem of point cloud completion from the perspective of feature learning. Our key observation is that to recover the... 相似文献
44.
Wireless Personal Communications - With the rapid development of information technology, issues such as network security and privacy protection have attracted more and more attention. The... 相似文献
45.
Chen Rongxin Wang Zhijin Su Hang Xie Shutong Wang Zongyue 《The Journal of supercomputing》2022,78(4):5420-5449
The Journal of Supercomputing - The performance of XPath query is the key factor to the capacity of XML processing. It is an important way to improve the performance of XPath by making full use of... 相似文献
46.
Neural Computing and Applications - A new iterative method based on the event-triggered strategy for finding a solution to a mixed equilibrium problem (MEP) is introduced in this paper. The target... 相似文献
47.
Designing Metallic and Insulating Nanocrystal Heterostructures to Fabricate Highly Sensitive and Solution Processed Strain Gauges for Wearable Sensors 下载免费PDF全文
Woo Seok Lee Seung‐Wook Lee Hyungmok Joh Mingi Seong Haneun Kim Min Su Kang Ki‐Hyun Cho Yun‐Mo Sung Soong Ju Oh 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(47)
All‐solution processed, high‐performance wearable strain sensors are demonstrated using heterostructure nanocrystal (NC) solids. By incorporating insulating artificial atoms of CdSe quantum dot NCs into metallic artificial atoms of Au NC thin film matrix, metal–insulator heterostructures are designed. This hybrid structure results in a shift close to the percolation threshold, modifying the charge transport mechanism and enhancing sensitivity in accordance with the site percolation theory. The number of electrical pathways is also manipulated by creating nanocracks to further increase its sensitivity, inspired from the bond percolation theory. The combination of the two strategies achieves gauge factor up to 5045, the highest sensitivity recorded among NC‐based strain gauges. These strain sensors show high reliability, durability, frequency stability, and negligible hysteresis. The fundamental charge transport behavior of these NC solids is investigated and the combined site and bond percolation theory is developed to illuminate the origin of their enhanced sensitivity. Finally, all NC‐based and solution‐processed strain gauge sensor arrays are fabricated, which effectively measure the motion of each finger joint, the pulse of heart rate, and the movement of vocal cords of human. This work provides a pathway for designing low‐cost and high‐performance electronic skin or wearable devices. 相似文献
48.
The acid-catalyzed ring-opening reaction of styrene oxide was used as a probe reaction for evaluating the acidic properties of carboxylated carbocatalysts. Significant discrepancies in the initial reaction rates were normalized using the total number of carboxyl groups, and demonstrated that the average catalytic activities of the carboxyl moieties on the carbocatalysts differed. Comparisons between the apparent activation energy E a and the pre-exponential factor A, derived from Arrhenius analysis, demonstrated that A varied more significantly, and therefore had a more significant effect on the reaction rates than E a. The variation in the calculated pKa values of the carboxyl groups was attributed to the electronic effects of the nitro groups. This hypothesis was supported by the temperature programmed desorption profiles of nitrogen monoxide ions. 相似文献
49.
Yike Li Zhenhua Wu Congcan Shi Yizhuo Xu Aotian Chen Bin Su 《Advanced Engineering Materials》2023,25(20):2300703
Flush toilets waste a significant amount of water every day due to the unavoidable adhesions between human waste and the toilet surfaces. Super-slippery surfaces can repel complex fluids and various viscoelastic solids, however, are easily broken by mechanical abrasions. Herein, the fabrication of an abrasion-resistant super-slippery flush toilet (ARSFT) is reported using a selective laser sintering 3D printing technology. Unlike traditional super-slippery surfaces with limited thicknesses which can be easily worn away, the powder-sintered strategy endows the ARSFT not only with a self-supporting 3D complex shape but also with a porous structure that can accommodate considerable lubricants for an abrasion-resistant super-slippery property. As a result, the as-prepared ARSFT remains clean after contacting with various liquids such as milk, yogurt, highly sticky honey, and starch gel mixed congee, demonstrating excellent repellence to complex fluids. Besides liquids, the ARSFT exhibits a high resistance to sticky synthetic feces. Notably, even after being abraded to 1,000 cycles of abrasion using sandpaper, the ARSFT maintains its record-breaking super-slippery capability. The concept of the 3D-printed object with a superior abrasion-resistant slippery ability will improve the development of super-slippery materials and further save water consumption in the human society. 相似文献
50.
Zixuan Wang Dongzhao Hao Yuefei Wang Jinwu Zhao Jiaxing Zhang Xi Rong Jiaojiao Zhang Jiwei Min Wei Qi Rongxin Su Mingxia He 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(1):2204959
The self-assembly of peptidyl virus-like nanovesicles (pVLNs) composed of highly ordered peptide bilayer membranes that encapsulate the small interfering RNA (siRNA) is reported. The targeting and enzyme-responsive sequences on the bilayer's surface allow the pVLNs to enter cancer cells with high efficiency and control the release of genetic drugs in response to the subcellular environment. By transforming its structure in response to the highly expressed enzyme matrix metalloproteinase 7 (MMP-7) in cancer cells, it helps the siRNA escape from the lysosomes, resulting in a final silencing efficiency of 92%. Moreover, the pVLNs can serve as reconfigurable “Trojan horse” by transforming into membranes triggered by the MMP-7 and disrupting the cytoplasmic structure, thereby achieving synergistic anticancer effects and 96% cancer cell mortality with little damage to normal cells. The pVLNs benefit from their biocompatibility, targeting, and enzyme responsiveness, making them a promising platform for gene therapy and anticancer therapy. 相似文献