全文获取类型
收费全文 | 5654篇 |
免费 | 382篇 |
国内免费 | 118篇 |
专业分类
电工技术 | 163篇 |
综合类 | 157篇 |
化学工业 | 1236篇 |
金属工艺 | 232篇 |
机械仪表 | 349篇 |
建筑科学 | 273篇 |
矿业工程 | 72篇 |
能源动力 | 200篇 |
轻工业 | 554篇 |
水利工程 | 67篇 |
石油天然气 | 133篇 |
武器工业 | 22篇 |
无线电 | 684篇 |
一般工业技术 | 930篇 |
冶金工业 | 391篇 |
原子能技术 | 68篇 |
自动化技术 | 623篇 |
出版年
2024年 | 25篇 |
2023年 | 96篇 |
2022年 | 165篇 |
2021年 | 227篇 |
2020年 | 150篇 |
2019年 | 171篇 |
2018年 | 182篇 |
2017年 | 180篇 |
2016年 | 169篇 |
2015年 | 201篇 |
2014年 | 254篇 |
2013年 | 373篇 |
2012年 | 339篇 |
2011年 | 391篇 |
2010年 | 333篇 |
2009年 | 313篇 |
2008年 | 332篇 |
2007年 | 212篇 |
2006年 | 231篇 |
2005年 | 192篇 |
2004年 | 145篇 |
2003年 | 155篇 |
2002年 | 152篇 |
2001年 | 138篇 |
2000年 | 114篇 |
1999年 | 125篇 |
1998年 | 165篇 |
1997年 | 122篇 |
1996年 | 93篇 |
1995年 | 93篇 |
1994年 | 73篇 |
1993年 | 32篇 |
1992年 | 45篇 |
1991年 | 34篇 |
1990年 | 18篇 |
1989年 | 24篇 |
1988年 | 15篇 |
1987年 | 20篇 |
1986年 | 10篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1982年 | 3篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1977年 | 4篇 |
1976年 | 8篇 |
1972年 | 1篇 |
1966年 | 2篇 |
1914年 | 2篇 |
排序方式: 共有6154条查询结果,搜索用时 13 毫秒
101.
Ji Qian Yang Ha Krishna Prasad Koirala Di Huang Zhi Huang Vincent S. Battaglia Chongmin Wang Wanli Yang Wei Tong 《Advanced functional materials》2023,33(22):2205972
The recently developed Li-excess cation-disordered rock salts (DRXs) exhibit an excellent chemical diversity for the development of alternative Co/Ni-free high-energy cathodes. Herein, the synthesis of a highly fluorinated DRX cathode, Li1.2Mn0.6Ti0.2O1.8F0.2, based on cost-effective and earth-abundant transition metals, via a solid-state reaction, is reported. The fluorinated DRX cathode using ammonium fluoride precursor exhibits more uniform particle size and delivers a specific discharge capacity of 233 mAh g−1 and specific energy of 754 Wh kg−1, with 206 mAh g−1 retained after 200 cycles. The combined synchrotron X-ray absorption spectroscopy and resonant inelastic X-ray scattering spectroscopy analysis reveals that the remarkable cycling performance is attributed to the high fluorination and thus enhanced Mn content, enabling the utilization of more Mn redox than the oxide analog. This study demonstrates a great promise to develop next-generation cost-effective DRX cathodes with enhanced capacity retention for high-energy Li-ion batteries. 相似文献
102.
Yiqian Du Zhikai Yan Wenbin You Qiaoqiao Men Guanyu Chen Xiaowei Lv Yuyang Wu Kaicheng Luo Biao Zhao Jincang Zhang Renchao Che 《Advanced functional materials》2023,33(34):2301449
Surface chemistry and interlayer engineering determines the electrical properties of 2D MXene. However, it remains challenging to regulate the surface and interfacial chemistry of MXene simultaneously. Herein, simultaneous modulation of Ti3C2Tx MXene surface termination and layer spacing by alkali treatment are achieved. The electrical and electromagnetic properties of Ti3C2Tx are investigated in detail with respect to KOH and ammonia concentration dependence. A high concentration of KOH caused the Ti3C2Tx layer spacing to expand to 13.7 Å and the surface O/F ratio to increase to 33.84. Because of its weaker ionization effect, ammonia provides finer tuning compared to the drastic intercalation of KOH with a thorough sweeping of the F-containing groups. Ti3C2Tx is enriched with conductive -OH termination after ammonia treatment, which achieves an effective balance with the increased interlayer resistance. Therefore, NH3H2O-Ti3C2Tx achieves broad-band impedance matching and exhibits an efficient microwave loss of −49.1 dB at a low thickness of 1.7 mm, with an effective frequency bandwidth of 3.9 GHz. The results herein optimize the electrical properties of Ti3C2Tx using surface and interfacial chemistry to achieve broad microwave absorption, providing a framework for enhancing the electromagnetic wave loss of intrinsic MXene. 相似文献
103.
104.
基于激光扫描技术的三维模型重建 总被引:4,自引:1,他引:4
通过分析三维激光扫描系统获取的点云数据,得到了利用点云数据构建三维模型的技术、方法和流程。介绍了利用地面三维激光扫描仪获取点云数据的过程以及结合RiSCAN PRO软件和Geomagic Studio软件进行建模的方法。对原始测量的点云数据进行处理(去除噪声,平滑,对多站点数据做拼接配准,提取目标建筑物等)得到正确和完整的目标建筑物的表面信息,然后构建三角网建立它的三维表面模型,最后通过所拍的照片进行纹理映射得到真实的三维模型。实验结果表明,利用上述方法可以有效地处理三维激光扫描获取的点云数据,实现对建筑物快速三维可视化建模。 相似文献
105.
Bioinspired Interlocked and Hierarchical Design of ZnO Nanowire Arrays for Static and Dynamic Pressure‐Sensitive Electronic Skins 下载免费PDF全文
Minjeong Ha Seongdong Lim Jonghwa Park Doo‐Seung Um Youngoh Lee Hyunhyub Ko 《Advanced functional materials》2015,25(19):2841-2849
The development of electronic skin (e‐skin) is of great importance in human‐like robotics, healthcare, wearable electronics, and medical applications. In this paper, a bioinspired e‐skin design of hierarchical micro‐ and nano‐structured ZnO nanowire (NW) arrays in an interlocked geometry is suggested for the sensitive detection of both static and dynamic tactile stimuli through piezoresistive and piezoelectric transduction modes, respectively. The interlocked hierarchical structures enable a stress‐sensitive variation in the contact area between the interlocked ZnO NWs and also the efficient bending of ZnO NWs, which allow the sensitive detection of both static and dynamic tactile stimuli. The flexible e‐skin in a piezoresistive mode shows a high pressure sensitivity (?6.8 kPa?1) and an ultrafast response time (<5 ms), which enables the detection of minute static pressure (0.6 Pa), vibration level (0.1 m s?2), and sound pressure (≈57 dB). The flexible e‐skin in a piezoelectric mode is also demonstrated to be able to detect fast dynamic stimuli such as high frequency vibrations (≈250 Hz). The flexible e‐skins with both piezoresistive and piezoelectric sensing capabilities may find applications requiring both static and dynamic tactile perceptions such as robotic hands for dexterous manipulations and various healthcare monitoring devices. 相似文献
106.
107.
Yanzhe Che Qinming He Xiaoyan Hong Kevin Chiew 《International Journal of Communication Systems》2015,28(1):167-186
While enjoying various LBS (location‐based services), users also face the threats of location privacy disclosure. This is because even if the communications between users and LBS providers can be encrypted and anonymized, the sensitive information inside LBS queries may disclose the exact location or even the identity of a user. The existing research on location privacy preservation in mobile peer‐to‐peer (P2P) networks assumed that users trust each other and directly share location information with each other. Nonetheless, this assumption is not practical for most of the mobile P2P scenarios, for example, an adversary can pretend to be a normal user and collect the locations of other users. Aiming at this issue, this paper presents x‐region as a solution to preserve the location privacy in a mobile P2P environment where no trust relationships are assumed amongst mobile users. The main idea is to allow users to share a blurred region known as x‐region instead of their exact locations so that one cannot distinguish any user from others inside the region. We propose a theoretical metric for measuring the anonymity property of x‐region, together with three algorithms for generating an x‐region, namely, benchmark algorithm, weighted expanding algorithm, and aggressive weighted expanding algorithm. These algorithms achieve the anonymity and QoS requirements with different strategies. Our experiments verify the performance of the algorithms against three key metrics. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
108.
Sumit Kumar Jae‐A Han Issac J. Michael Dongyeob Ki Vijaya Sunkara Juhee Park Shreedhar Gautam Hong Koo Ha Liangfang Zhang Yoon‐Kyoung Cho 《Advanced functional materials》2019,29(30)
The possibility of functional roles played by platelets in close alliance with cancer cells has inspired the design of new biomimetic systems that exploit platelet–cancer cell interactions. Here, the role of platelets in cancer diagnostics is leveraged to design a microfluidic platform capable of detecting cancer‐derived extracellular vesicles (EVs) from ultrasmall volumes (1 µL) of human plasma samples. Further, the captured EVs are counted by direct optical coding of plasmonic nanoprobes modified with EV‐specific antibodies. Owing to the inherent properties of platelets for multifaceted interaction with cancer cells, the microfluidic chip equipped with a biologically interfaced platelet membrane‐cloaked surface (denoted “PLT‐Chip”) can capture a significantly higher number of EVs from multiple types of cancer cell lines (prostate, lung, bladder, and breast) than the normal cell‐derived EVs. Furthermore, this chip allows the monitoring of the growth of tumor spheroids (100 µm–2.5 mm) and clearly distinguishes the plasma of cancer patients from that of normal healthy controls. This robust, multifaceted, and cancer‐specific binding affinity, coupled with excellent biocompatibility, is a unique feature of platelet membrane‐cloaked surfaces, which therefore represent promising alternatives to antibodies for application in EVs‐based cancer theranostics. 相似文献
109.
Jiyoon Kim Jongin Hong Moonkyu Park Wu Zhe Dongjin Kim Yu Jin Jang Dong Ha Kim Kwangsoo No 《Advanced functional materials》2011,21(22):4277-4284
A facile route is presented for the fabrication of spherical PbTiO3 (PTO) nanodot arrays on platinized silicon substrates using PbO vapor phase reaction sputtering on micellar monolayer films of polystyrene‐block‐poly(ethylene oxide) (PS‐b‐PEO) loaded with TiO2 sol–gel precursor. Short exposure to PbO transforms the amorphous TiO2 into polycrystalline PTO, while keeping the inherent size and periodicity of TiO2 nanodots. HRTEM images show that the spherical PTO nanodots, with an average size and height of 63 nm and 40 nm, respectively, are fixed on the Pt supported by residual carbon. XPS narrow scan spectra of Ti 2p and O 1s strongly verify the evolution of chemical identity and the reduction of the Ti‐O binding energy from TiO2 to PTO. The amplitude and phase images of piezoelectric force microscopy (PFM) confirm a multidomain structure attributed by the crystalline orientation of the PTO nanodots. Furthermore, the discrete PTO nanodots show remarkable switching properties due to the low strain field induced by the small lateral size, and the absence of domain pinning effects by grain boundary. 相似文献
110.
Morphological Stabilization by Supramolecular Perfluorophenyl‐C60 Interactions Leading to Efficient and Thermally Stable Organic Photovoltaics 下载免费PDF全文
Ming‐Hung Liao Che‐En Tsai Yu‐Ying Lai Fong‐Yi Cao Jhong‐Sian Wu Chien‐Lung Wang Chain‐Shu Hsu Ian Liau Yen‐Ju Cheng 《Advanced functional materials》2014,24(10):1418-1429
A new PC61BM‐based fullerene, [6,6]‐phenyl‐C61 butyric acid pentafluorophenyl ester (PC61BPF) is designed and synthesized. This new n‐type material can replace PC61BM to form a P3HT:PC61BPF binary blend or serve as an additive to form a P3HT:PC61BM:PC61BPF ternary blend. Supramolecular attraction between the pentafluorophenyl group of PC61BPF and the C60 cores of PC61BPF/PC61BM can effectively suppress the PC61BPF/PC61BM materials from severe aggregation. By doping only 8.3 wt% PC61BPF, device PC61BPF651 exhibits a PCE of 3.88% and decreases slightly to 3.68% after heating for 25 h, preserving 95% of its original value. When PC61BP with non‐fluorinated phenyl group is used to substitute PC61BPF, the stabilizing ability disappears completely. The efficiencies of PC61BP651 and PC61BP321 devices significantly decay to 0.44% and 0.11%, respectively, after 25 h isothermal heating. Most significantly, this strategy is demonstrated to be effective for a blend system incorporating a low band‐gap polymer. By adding only 10 wt% PC61BPF, the PDTBCDTB: PC71BM‐based device exhibits thermally stable morphology and device characteristics. These findings demonstrate that smart utilization of supramolecular interactions is an effective and practical strategy to control morphological evolution. 相似文献