全文获取类型
收费全文 | 542篇 |
免费 | 33篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 17篇 |
化学工业 | 139篇 |
金属工艺 | 4篇 |
机械仪表 | 6篇 |
建筑科学 | 13篇 |
矿业工程 | 3篇 |
能源动力 | 19篇 |
轻工业 | 43篇 |
水利工程 | 5篇 |
无线电 | 26篇 |
一般工业技术 | 154篇 |
冶金工业 | 62篇 |
原子能技术 | 8篇 |
自动化技术 | 80篇 |
出版年
2023年 | 6篇 |
2022年 | 10篇 |
2021年 | 17篇 |
2020年 | 17篇 |
2019年 | 12篇 |
2018年 | 21篇 |
2017年 | 23篇 |
2016年 | 29篇 |
2015年 | 16篇 |
2014年 | 24篇 |
2013年 | 49篇 |
2012年 | 32篇 |
2011年 | 33篇 |
2010年 | 29篇 |
2009年 | 23篇 |
2008年 | 23篇 |
2007年 | 21篇 |
2006年 | 17篇 |
2005年 | 12篇 |
2004年 | 14篇 |
2003年 | 12篇 |
2002年 | 9篇 |
2001年 | 5篇 |
2000年 | 9篇 |
1999年 | 6篇 |
1998年 | 21篇 |
1997年 | 16篇 |
1996年 | 8篇 |
1995年 | 4篇 |
1994年 | 8篇 |
1993年 | 9篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 9篇 |
1979年 | 4篇 |
1977年 | 2篇 |
1976年 | 6篇 |
排序方式: 共有579条查询结果,搜索用时 93 毫秒
1.
A. Balčiūnaitė Z. Sukackienė K. Antanavičiūtė J. Vaičiūnienė A. Naujokaitis L. Tamašauskaitė-Tamašiūnaitė E. Norkus 《International Journal of Hydrogen Energy》2021,46(2):1989-1996
Effective Co/Cu, CoB/Cu, and CoBM (M = Mo,Zn,Fe)/Cu catalysts were prepared on the copper surface by a simple electroless deposition method using a morpholine borane as a reducing agent in the glycine solution. The activity of the deposited catalysts was investigated for hydrogen generation from an alkaline sodium borohydride solution. It was determined that these synthesized catalysts demonstrated the catalytic activity for the hydrolysis reaction of NaBH4. The lowest obtained activation energy (EA) of the hydrolysis reaction of NaBH4was 27 kJ mol?1 for the CoBMo/Cu catalyst. The hydrogen generation rate of 15.30 ml min?1 was achieved using CoBMo/Cu catalysts at 313 K and it increased ~3.5 times with the increase of temperature to 343 K. The highest hydrogen generation rate obtained by CoBMo/Cu films may be related to the hierarchical cauliflower-shaped 3D structures and the high roughness surface area. Moreover, the CoBMo/Cu catalyst showed an excellent reusability. 相似文献
2.
Machine Learning - We propose a data-driven approach to quantify the uncertainty of models constructed by kernel methods. Our approach minimizes the needed distributional assumptions, hence,... 相似文献
3.
We present a novel method for the unsupervised discovery of behavioural motifs in larval Drosophila melanogaster and Caenorhabditis elegans. A motif is defined as a particular sequence of postures that recurs frequently. The animal''s changing posture is represented by an eigenshape time series, and we look for motifs in this time series. To find motifs, the eigenshape time series is segmented, and the segments clustered using spline regression. Unlike previous approaches, our method can classify sequences of unequal duration as the same motif. The behavioural motifs are used as the basis of a probabilistic behavioural annotator, the eigenshape annotator (ESA). Probabilistic annotation avoids rigid threshold values and allows classification uncertainty to be quantified. We apply eigenshape annotation to both larval Drosophila and C. elegans and produce a good match to hand annotation of behavioural states. However, we find many behavioural events cannot be unambiguously classified. By comparing the results with ESA of an artificial agent''s behaviour, we argue that the ambiguity is due to greater continuity between behavioural states than is generally assumed for these organisms. 相似文献
4.
Corina Danciu Szilvia Berkó Gábor Varju Boglárka Balázs Lajos Kemény István Balázs Németh Andreea Cioca Alexandra Petru? Cristina Dehelean Citu Ioan Cosmin Elena Amaricai Claudia Crina Toma 《International journal of molecular sciences》2015,16(7):15425-15441
A lamellar lyotropic liquid crystal genistein-based formulation (LLC-Gen) was prepared in order to increase the aqueous solubility of the lipophilic phytocompound genistein. The formulation was applied locally, in a murine model of melanoma, with or without electroporation. The results demonstrated that, when the formulation was applied by electroporation, the tumors appeared later. During the 21 days of the experiment, the LLC-Gen formulation decreased the tumor volume, the amount of melanin and the degree of erythema, but when electroporation was applied, all these parameters indicated a better prognosis even (lower tumor volume, amount of melanin and degree of erythema). Although hematoxylin–eosin (HE) staining confirmed the above events, application of the LLC-Gen formulation by electroporation did not lead to a significant effect in terms of the serum concentrations of the protein S100B and serum neuron specific enolase (NSE), or the tissue expression of the platelet-derived growth factor receptor β (PDGFRβ) antibody. 相似文献
5.
Bence Németh Ágnes S. Németh Aurél Ujhidy Judit Tóth László Trif Hajnalka Jankovics Balázs Kriszt Csaba Dobolyi Zoltán May János Gyenis Tivadar Feczkó 《国际能源研究杂志》2020,44(14):11998-12014
Latent heat storage by phase change materials (PCM) is a promising way of thermal energy storage for equilibrating the daily fluctuation of temperature in office- and home buildings. Bio-originated compounds have got great importance to evade further plastic contamination all over the world. Durability of biodegradable natural materials by means of environmentally friendly agents is an exciting challenge. In this study Ca alginate-coconut oil eco-friendly core-shell PCM microcapsules were functionalized with Ag nanoparticles, following their synthesis using harmless reducing agents. Throughout the preparation of the PCM microcapsules by repeated interfacial coacervation/crosslinking procedure, the Ag nanoparticles were homogeneously dispersed in the Ca alginate shell. High coconut oil content was achieved in the Ag nanoparticle-loaded microcapsules, which was not influenced by the Ag nanoparticle content. The high PCM content resulted in correspondingly high latent heat storing capability. The freezing and melting heat storing capacities were in the range of 83.6 and 85.6 J/g, as well as 89.7 to 92.6 J/g, respectively, matching to the extremely high PCM content in the range of 82.7% to 84.8% (m/m). Leaking of the heat storing microcapsules was not observed after 200 heating-cooling cycles. The Ag nanoparticle content did not influence the PCM ratio of the microcapsules, although as expected their antimicrobial potential was significantly enhanced by it. The highest Ag nanoparticle loading, that was 1.3% (m/m) related to the total mass of microcapsules, exerted excellent antibacterial and antifungal impact. 相似文献
6.
Dr. Erika Lisztes Dr. Erika Mező Fruzsina Demeter Lilla Horváth Dr. Szilvia Bősze Dr. Balázs István Tóth Prof. Anikó Borbás Dr. Mihály Herczeg 《ChemMedChem》2021,16(9):1467-1476
The design and synthesis of heparin mimetics with high anticancer activity but no anticoagulant activity is an important task in medicinal chemistry. Herein, we present the efficient synthesis of five Glc-GlcA-Glc-sequenced and one Glc-IdoA-Glc-sequenced non-glycosaminoglycan, heparin-related trisaccharides with various sulfation/sulfonylation and methylation patterns. The cell growth inhibitory effects of the compounds were tested against four cancerous human cell lines and two non-cancerous cell lines. Two d -glucuronate-containing tetra-O-sulfated, partially methylated trisaccharides displayed remarkable and selective inhibitory effects on the growth of ovary carcinoma (A2780) and melanoma (WM35) cells. Methyl substituents on the glucuronide unit proved to be detrimental, whereas acetyl substituents were beneficial to the cytostatic activity of the sulfated derivatives. 相似文献
7.
Dutková Erika Sayagués María Jesús Fabián Martin Kováč Jaroslav Kováč Jaroslav Baláž Matej Stahorský Martin 《Journal of Materials Science: Materials in Electronics》2021,32(18):22898-22909
Journal of Materials Science: Materials in Electronics - In this work, the very rapid one-step mechanochemical synthesis of nanocrystalline ternary chalcogenide chalcostibite CuSbS2 prepared from... 相似文献
8.
Balázs Rakos 《International Journal of Circuit Theory and Applications》2020,48(12):2130-2140
Today's society has an ever-increasing demand for smaller-scale, lower-energy-consuming, cheaper, and faster computing and digital signal processing systems. Photon-coupled, fluorescent photoswitchable protein-based architectures are promising candidates for the fulfillment of these requirements. In order to properly design digital circuits based on the aforementioned building blocks, an efficient simulation procedure is needed. We present a simple, differential equation-based model, suitable for the design and simulation of such structures. It characterizes the radiation-induced switching, the form-dependent fluorescence, and the effect of photon coupling in a fast and efficient manner. The applicability of the model is demonstrated through simulations of the OR and NOR logic gates consisting of readily available, fluorescent photoswitchable proteins. It can be a potential design tool for future molecular logic circuitry based on such molecules. 相似文献
9.
When chloramine is used as a disinfectant, managing an acceptable “residual” throughout the water distribution systems particularly once nitrification has set in is challenging. Managing chloramine decay prior to the onset of nitrification through effective control strategies is important and to-date the strategies developed around nitrification has been ineffective. This study aimed at developing a more holistic knowledge on how decaying chloramine and nitrification metabolites impact microbial communities in chloraminated systems. Five lab-scale reactors (connected in series) were operated to simulate a full-scale chloraminated distribution system. Culture independent techniques (cloning and qPCR) were used to characterise and quantify the mixed microbial communities in reactors maintaining a residual of high to low (2.18–0.03 mg/L). The study for the first time associates chloramine residuals and nitrification metabolites to different microbial communities. Bacterial classes Solibacteres, Nitrospira, Sphingobacteria and Betaproteobacteria dominated at low chloramine residuals whereas Actinobacteria and Gammaproteobacteria dominated at higher chloramine residuals. Prior to the onset of nitrification bacterial genera Pseudomonas, Methylobacterium and Sphingomonas were found to be dominant and Sphingomonas in particular increased with the onset of nitrification. Nitrosomonas urea, oligotropha, and two other novel ammonia-oxidizing bacteria were detected once the chloramine residuals had dropped below 0.65 mg/L. Additionally nitrification alone failed to explain chloramine decay rates observed in these reactors. The finding of this study is expected to re-direct the focus from nitrifiers to heterotrophic bacteria, which the authors believe could hold the key towards developing a control strategy that would enable better management of chloramine residuals. 相似文献
10.
B. A. Belyaev A. A. Leksikov A. M. Serzhantov V. V. Tyurnev Ya. F. Bal’va An. A. Leksikov 《Journal of Communications Technology and Electronics》2013,58(2):110-117
Characteristics of a new miniaturized coaxial resonator are theoretically investigated. It is shown that the first resonant frequency of the resonator can be significantly lowered relative to the second one and the resonator dimensions can be considerably decreased as compared to those of a traditional dielectric-filled quarter-wavelength coaxial resonator. Based on the investigated resonator, a fourth-order bandpass filter has been designed and fabricated. The filter stopband at a level of no worse than ?90 dB extends to the frequency that exceeds the passband center frequency by a factor of 47. Calculated frequency responses are in good agreement with those measured on the fabricated filter prototypes. 相似文献