全文获取类型
收费全文 | 572篇 |
免费 | 29篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 11篇 |
综合类 | 1篇 |
化学工业 | 141篇 |
金属工艺 | 13篇 |
机械仪表 | 11篇 |
建筑科学 | 34篇 |
能源动力 | 14篇 |
轻工业 | 39篇 |
石油天然气 | 1篇 |
武器工业 | 1篇 |
无线电 | 41篇 |
一般工业技术 | 161篇 |
冶金工业 | 61篇 |
原子能技术 | 3篇 |
自动化技术 | 70篇 |
出版年
2023年 | 8篇 |
2022年 | 15篇 |
2021年 | 20篇 |
2020年 | 16篇 |
2019年 | 12篇 |
2018年 | 10篇 |
2017年 | 15篇 |
2016年 | 16篇 |
2015年 | 18篇 |
2014年 | 20篇 |
2013年 | 50篇 |
2012年 | 29篇 |
2011年 | 34篇 |
2010年 | 23篇 |
2009年 | 21篇 |
2008年 | 23篇 |
2007年 | 22篇 |
2006年 | 18篇 |
2005年 | 22篇 |
2004年 | 22篇 |
2003年 | 17篇 |
2002年 | 18篇 |
2001年 | 8篇 |
2000年 | 5篇 |
1999年 | 4篇 |
1998年 | 7篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 10篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1985年 | 6篇 |
1984年 | 7篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 8篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1976年 | 3篇 |
1968年 | 3篇 |
1966年 | 3篇 |
1938年 | 3篇 |
1937年 | 3篇 |
1928年 | 2篇 |
1913年 | 3篇 |
1912年 | 2篇 |
排序方式: 共有602条查询结果,搜索用时 31 毫秒
591.
Wireless networks dynamically coexist when their transmission ranges overlap as a result of mobility. Mobile wireless sensor networks (WSNs) may suffer from significant degradation of performance due to the interference caused by dynamic coexistence, which is particularly critical for health monitoring WSNs. In this paper, we propose a novel method to detect and mitigate the harmful effects of dynamic coexistence on the operation of IEEE 802.15.4‐based mobile health monitoring WSNs. IEEE 802.15.4 uses the guaranteed time slots (GTS) mechanism to eliminate contention; however, successful transmissions cannot be guaranteed for coexisting WSNs. We show that using limited clear channel assessments at the beginning of the GTS enables the mobile WSNs to avoid collisions with minimum overhead. This method can also be used in combination with the previously proposed mechanisms for coexistence management. We analytically investigate the effects of using this method on the performance of the dynamically coexisting WSNs. We use OPNET simulation to investigate the coexistence of health monitoring WSNs and also to validate the proposed method. Our results indicate that using the proposed mechanism, 2–10 coexisting mobile WSNs with relatively high transmission rates (20–30% of maximum throughput) can achieve 20–90% higher rates of successful transmissions, with less than 10% increase in power consumption. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
592.
Mesoporous Silica: A Perfectly Periodic Three‐Dimensional Protein/Silica Mesoporous Structure Produced by an Organism (Adv. Mater. 11/2014) 下载免费PDF全文
593.
Roasted Sunflower Kernel Paste (Tahini) Stability: Storage Conditions and Particle Size Influence 下载免费PDF全文
Vlad Mureşan Sabine Danthine Sorana D. Bolboacă Emil Racolţa Sevastiţa Muste Carmen Socaciu Christophe Blecker 《Journal of the American Oil Chemists' Society》2015,92(5):669-683
Sunflower tahini faces quality problems due to the tendency of oil to exudate, causing accelerated rancidity and low marketability. In this study, the colloidal and oxidative stability of different trimodal particle size distributions of sunflower tahini (cumulative volume percentages of small, middle and large class populations of 9.61–16.67, 43.03–55.03 and 47.36–28.3) was evaluated during storage at three different temperatures. Decreasing sample particle size decreased the sunflower tahini colloidal stability. The coarsest prototype, being the most stable tahini in terms of oil separation, was included in the oxidative stability storage test together with a commercial tahini. The peroxide values of the studied sunflower tahini samples increased significantly (p < 0.05) with storage time, irrespective of storage temperature, while the p‐anisidine values showed an irregular pattern. Considering 30‐meq O2/kg as a PV limit, the commercial tahini showed good oxidative stability as it was under this when stored 3 months at 4 °C, 2 months at room temperature and 1 month at 40 °C. The coarsest tahini sample was under the limit when stored 2 months at 4 °C, 1 month at room temperature and 2 weeks at 40 °C. Particle size was shown to be an essential parameter for controlling sunflower tahini's overall stability. 相似文献
594.
Regina Komsa-Penkova Avgustina Danailova Sashka Krumova Galya Georgieva Ina Giosheva Lidia Gartcheva Ivan Iliev Emil Gartchev Kameliya Kercheva Alexey Savov Svetla Todinova 《International journal of molecular sciences》2022,23(15)
Early pregnancy loss (EPL) is a relatively common pathology of which almost 50% of cases remain idiopathic. In the search for novel biomarkers, differential scanning calorimetry (DSC) is intensively used to characterize the thermodynamic behavior of blood plasma/serum proteome in health and disease. Herein, for the first time, we investigate the DSC denaturation profiles of blood plasma derived from patients suffering EPL compared to healthy pregnant and non-pregnant women. Data analysis reveals that 58% of the EPL thermograms differ significantly from those of healthy pregnant women. Thermal stabilization of a fraction of albumin-assigned transition with concomitant suppression of the major and enhancement of the globulin-assigned transition are characteristic features of EPL calorimetric profiles that could be used as a new indicator of a risk pregnancy. The presented results suggest an altered composition or intermolecular interactions of the plasma proteome of women with EPL. In addition, the alterations of the EPL thermograms correlate with the increased blood levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) and a higher prevalence of the polymorphism in the plasminogen activator inhibitor type-1 (PAI-1) gene, suggesting an expression of an overall enhanced immune response. The concomitant changes in plasma thermograms confirm the potential of the DSC approach for distinguishing changes in the pathological state of the blood plasma proteome. 相似文献
595.
596.
Ana F. Suzana Sizhan Liu Jiecheng Diao Longlong Wu Tadesse A. Assefa Milinda Abeykoon Ross Harder Wonsuk Cha Emil S. Bozin Ian K. Robinson 《Advanced functional materials》2023,33(19):2208012
When synthesized under certain conditions, barium titanate (BaTiO3, BTO) nanoparticles are found to have the non-thermodynamic cubic structure at room temperature. These particles also have a several-fold enhanced dielectric constant, sometimes exceeding 6000, and are widely used in thin-layer capacitors. A hydrothermal approach is used to synthesize BTO nanocrystals, which are characterized by a range of methods, including X-ray Rietveld refinement and the Williamson–Hall approach, revealing the presence of significant inhomogeneous strain associated with the cubic phase. However, X-ray pair distribution function measurements clearly show the local structure is lower symmetry than cubic. This apparent inconsistency is resolved by examining 3D Bragg coherent diffraction images of selected nanocrystals, which show the existence of ≈50 nm-sized domains, which are interpreted as tetragonal twins, and yet cause the average crystalline structure to appear cubic. The ability of these twin boundaries to migrate under the influence of electric fields explains the dielectric anomaly for the nanocrystalline phase. 相似文献
597.
Chao Chen Kexin Wang Hongying He Emil Hanc Masashi Kotobuki Li Lu 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(12):2205550
Garnet-type solid electrolyte Li7La3Zr2O12 (LLZO) is widely considered as one of the most promising candidates for solid state batteries (SSBs) owing to its high ionic conductivity and good electrochemical stability. Since its discovery in 2007, great progress has been made in terms of crystal chemistry, chemical and electrochemical properties, and battery application. Nonetheless, reliable and controllable preparation of LLZO ceramics with desirable properties still remains as big challenges. Herein, this review summarizes various synthetic routes of LLZO ceramics and examines the influence of various key processing parameters on the chemical and electrochemical properties. Focusing on correlation of processing parameters and properties, this review aims to provide new insights on a reliable and controllable production of high-quality LLZO ceramic electrolytes for SSB application. 相似文献
598.
Emil Selvan Gnanasigamani Samuel Raj Issac Diana Jeba Jingle Balajee Maram John Patrick Ananth 《International Journal of Adaptive Control and Signal Processing》2023,37(1):224-243
The Internet of Things (IoT) has tremendously spread worldwide, and it influenced the world through easy connectivity, interoperability, and interconnectivity using IoT devices. Numerous techniques have been developed using IoT-enabled health care systems for cancer detection, but some limitations exist in transmitting the health data to the cloud. The limitations can be accomplished using the proposed chronological-based social optimization algorithm (CBSOA) that effectively transmits the patient's health data using IoT network, thereby detecting lung cancer in an effective way. Initially, nodes in the IoT network are simulated such that patient's health data are collected, and for transmission of such data, routing is performed in order to transmit the health data from source to destination through a gateway based on cloud service using CBSOA. The fitness is newly modeled by assuming the factors like energy, distance, trust, delay, and link quality. Finally, lung cancer detection is carried out at the destination point. At the destination point, the acquired input data is fed to preprocessing phase to make the data acceptable for further mechanism using data normalization. Once the feature selection is done using Canberra distance, then the lung cancer detection is performed using shepard convolutional neural network (ShCNN). The process of routing as well as training of ShCNN is performed using the CBSOA algorithm, which is devised by the inclusion of the chronological concept into the social optimization algorithm. The proposed approach has achieved a maximum accuracy of 0.940, maximum sensitivity of 0.941, maximum specificity of 0.928, and minimum energy of 0.452. 相似文献
599.
Khan Lê Florian von Toperczer Feray Ünlü Gopinath Paramasivam Florian Mathies Edgar Nandayapa Emil J. W. List-Kratochvil Thomas Fischer Klas Lindfors Sanjay Mathur 《Advanced Engineering Materials》2023,25(10):2201651
Thin-film perovskite light-emitting diodes have gained increasing attention in the last 6 years. With the possibility to process the emitting layer from solution, the way for 1D morphology of the semiconductor for flexible devices is paved. Herein, for the first time single-step fabrication of CsPbBr3@PVP nanofibers in a customized electrospinning process performed under ambient conditions from a water-based precursor solution is reported. The water-based approach allows the incorporation of a conductive polymer into the compound fiber by blending the perovskite precursor ink with commercially available PEDOT:PSS dispersion. The results demonstrate electrospun fiber mats which are stable at ambient conditions for at least 5 months and can be utilized in electroluminescence devices. Photoluminescence studies on the perovskite fibers reveal a blueshift of the emission peak compared to thin films possibly due to the generation of nanocrystals of ≈12 nm by in situ nanocrystal pinning as confirmed by transmission electron microscopy. A proof-of-concept electrically pumped light-emitting device is built with the obtained fiber mat. The perovskite nanofibers offer promising applications in flexible and stretchable optoelectronics. 相似文献
600.
Luyao Wang Qingbo Wang Emil Rosqvist Jan-Henrik Smått Qiwen Yong Lippo Lassila Jouko Peltonen Thomas Rosenau Martti Toivakka Stefan Willför Patrik Eklund Chunlin Xu Xiaoju Wang 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(24):2207085
Fabricating bio-latex colloids with core–shell nanostructure is an effective method for obtaining films with enhanced mechanical characteristics. Nano-sized lignin is rising as a class of sustainable nanomaterials that can be incorporated into latex colloids. Fundamental knowledge of the correlation between surface chemistry of lignin nanoparticles (LNPs) and integration efficiency in latex colloids and from it thermally processed latex films are scarce. Here, an approach to integrate self-assembled nanospheres of allylated lignin as the surface-activated cores in a seeded free-radical emulsion copolymerization of butyl acrylate and methyl methacrylate is proposed. The interfacial-modulating function on allylated LNPs regulates the emulsion polymerization and it successfully produces a multi-energy dissipative latex film structure containing a lignin-dominated core (16% dry weight basis). At an optimized allyl-terminated surface functionality of 1.04 mmol g−1, the LNPs-integrated latex film exhibits extremely high toughness value above 57.7 MJ m−3. With multiple morphological and microstructural characterizations, the well-ordered packing of latex colloids under the nanoconfinement of LNPs in the latex films is revealed. It is concluded that the surface chemistry metrics of colloidal cores in terms of the abundance of polymerization-modulating anchors and their accessibility have a delicate control over the structural evolution of core–shell latex colloids. 相似文献