全文获取类型
收费全文 | 252篇 |
免费 | 17篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 2篇 |
综合类 | 1篇 |
化学工业 | 81篇 |
金属工艺 | 5篇 |
机械仪表 | 7篇 |
建筑科学 | 3篇 |
能源动力 | 4篇 |
轻工业 | 7篇 |
水利工程 | 1篇 |
石油天然气 | 8篇 |
无线电 | 18篇 |
一般工业技术 | 90篇 |
冶金工业 | 14篇 |
原子能技术 | 6篇 |
自动化技术 | 24篇 |
出版年
2023年 | 6篇 |
2022年 | 25篇 |
2021年 | 15篇 |
2020年 | 18篇 |
2019年 | 23篇 |
2018年 | 8篇 |
2017年 | 13篇 |
2016年 | 13篇 |
2015年 | 11篇 |
2014年 | 7篇 |
2013年 | 9篇 |
2012年 | 15篇 |
2011年 | 16篇 |
2010年 | 11篇 |
2009年 | 9篇 |
2008年 | 6篇 |
2007年 | 8篇 |
2006年 | 11篇 |
2005年 | 6篇 |
2004年 | 2篇 |
2003年 | 1篇 |
2002年 | 1篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1992年 | 1篇 |
1989年 | 1篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1975年 | 2篇 |
1973年 | 2篇 |
1971年 | 1篇 |
1970年 | 3篇 |
1969年 | 2篇 |
1967年 | 1篇 |
1965年 | 1篇 |
1961年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有271条查询结果,搜索用时 15 毫秒
1.
The steady-state two-dimensional problem of the radiative-conductive heat transfer in a cylindrical monocrystal is solved. The solution is obtained numerically by the time-independent technique. Convergence of the iteration process is achieved by including the relation between the intensity of the nonlinear source in the energy equation and the desired temperature field at a particular time step. An algorithm for calculating the intensity field and the nonlinear source is given. In calculating the first approximation of the temperature distribution, the method of moments is used. The results obtained are given.Moscow Institute of Railroad Transport Engineers, Moscow, Russia. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 66, No. 1, pp. 76–82, January, 1994. 相似文献
2.
Aleksandr Drozd Olaf Witkowski Satoshi Matsuoka Takashi Ikegami 《Artificial Life and Robotics》2016,21(3):317-323
We extend an abstract agent-based swarming model based on the evolution of neural network controllers, to explore further the emergence of swarming. Our model is grounded in the ecological situation, in which agents can access some information from the environment about the resource location, but through a noisy channel. Swarming critically improves the efficiency of group foraging, by allowing agents to reach resource areas much more easily by correcting individual mistakes in group dynamics. As high levels of noise may make the emergence of collective behavior depend on a critical mass of agents, it is crucial to reach sufficient computing power to allow for the evolution of the whole set of dynamics in simulation. Since simulating neural controllers and information exchanges between agents are computationally intensive, to scale up simulations to model critical masses of individuals, the implementation requires careful optimization. We apply techniques from astrophysics known as treecodes to compute the signal propagation, and efficiently parallelize for multi-core architectures. Our results open up future research on signal-based emergent collective behavior as a valid collective strategy for uninformed search over a domain space. 相似文献
3.
Kseniia A. Sergeeva Dmitrii V. Pavlov Albert A. Seredin Eugeny V. Mitsai Aleksandr A. Sergeev Evgeny B. Modin Anastasiia V. Sokolova Tsz Chun Lau Kseniia V. Baryshnikova Mihail I. Petrov Stephen V. Kershaw Aleksandr A. Kuchmizhak Kam Sing Wong Andrey L. Rogach 《Advanced functional materials》2023,33(44):2307660
In order to advance the development of quantum emitter-based devices, it is essential to enhance light-matter interactions through coupling between semiconductor quantum dots with high quality factor resonators. Here, efficient tuning of the emission properties of HgTe quantum dots in the infrared spectral region is demonstrated by coupling them to a plasmonic metasurface that supports bound states in the continuum. The plasmonic metasurface, composed of an array of gold nanobumps, is fabricated using single-step direct laser printing, opening up new opportunities for creating exclusive 3D plasmonic nanostructures and advanced photonic devices in the infrared region. A 12-fold enhancement of the photoluminescence in the 900–1700 nm range is observed under optimal coupling conditions. By tuning the geometry of the plasmonic arrays, controllable shaping of the emission spectra is achieved, selectively enhancing specific wavelength ranges across the emission spectrum. The observed enhancement and shaping of the emission are attributed to the Purcell effect, as corroborated by systematic measurements of radiative lifetimes and optical simulations based on the numerical solution of Maxwell's equations. Moreover, coupling of the HgTe photoluminescence to high quality factor modes of the metasurface improves emission directivity, concentrating output within an ≈20° angle. 相似文献
4.
L. I. Urbanovich V. A. Goryainov V. V. Sevost'yanov Yu. G. Boev V. M. Niskovskikh A. V. Grachev A. V. Sevost'yanov V. S. Gur'ev 《Journal of Engineering Physics and Thermophysics》1980,39(2):900-905
A method is described and certain results presented of an experimental study of local heat exchange in the forced cooling of metal surfaces heated to high temperatures.Notation
l
distance from nozzle to heated surface
- x, y
horizontal and vertical coordinates in the field of the jet, read from the geometric center of the jet
- V
volumetric flow rate of water through the nozzle
- p
excess pressure of the water in front of the jet
- F0
area of sprayed surface of specimen
- Fc
area of unsprayed surface of working part of specimen
- t
temperature of sprayed surface of specimen
- tw
temperature of the water entering the nozzle
- N, Nc
power required to heat the working part of the specimen to a given temperature with and without the spraying of water onto the surface, respectively
- g
local spraying density
-
local heat-transfer coefficient
Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 39, No. 2, pp. 315–322, August, 1980. 相似文献
5.
Inhibition of hIAPP Amyloid Aggregation and Pancreatic β‐Cell Toxicity by OH‐Terminated PAMAM Dendrimer
下载免费PDF全文
![点击此处可从《Small (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Esteban N. Gurzov Bo Wang Emily H. Pilkington Pengyu Chen Aleksandr Kakinen William J. Stanley Sara A. Litwak Eric G. Hanssen Thomas P. Davis Feng Ding Pu Chun Ke 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(12):1615-1626
Human islet amyloid polypeptide (hIAPP, or amylin) forms amyloid deposits in the islets of Langerhans, a phenomenon that is associated with type‐2 diabetes impacting millions of people worldwide. Accordingly, strategies against hIAPP aggregation are essential for the prevention and eventual treatment of the disease. Here, it is shown that generation‐3 OH‐terminated poly(amidoamine) dendrimer, a polymeric nanoparticle, can effectively halt the aggregation of hIAPP and shut down hIAPP toxicity in pancreatic MIN6 and NIT‐1 cells as well as in mouse islets. This finding is supported by high‐throughput dynamic light scattering experiment and thioflavin T assay, where the rapid evolution of hIAPP nucleation and elongation processes is halted by the addition of the dendrimer up to 8 h. Discrete molecular dynamics simulations further reveal that hIAPP residues bound strongly with the dendrimer near the c‐terminal portion of the peptide, where the amyloidogenic sequence (residues 22–29) locates. Furthermore, simulations of hIAPP dimerization reveal that binding with the dendrimer significantly reduces formation of interpeptide contacts and hydrogen bonds, thereby prohibiting peptide self‐association and amyloidosis. This study points to a promising nanomedicinal strategy for combating type‐2 diabetes and may have broader implications for targeting neurological disorders whose distinct hallmark is also amyloid fibrillation. 相似文献
6.
V. B. Goryainov 《Automation and Remote Control》2012,73(8):1371-1379
Asymptotic normalcy of the M-estimates of the autoregression field coefficients on the planar rectangular lattice was proved. Consideration was given to the robust properties of the M-estimates. Efficiencies of the M-estimates and the least-squares estimators were compared. 相似文献
7.
Microwave Sol–Gel Synthesis of CaGd2(MoO4)4:Er3+/Yb3+ Phosphors and Their Upconversion Photoluminescence Properties
下载免费PDF全文
![点击此处可从《Journal of the American Ceramic Society》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Chang Sung Lim Victor Atuchin Aleksandr Aleksandrovsky Maxim Molokeev Aleksandr Oreshonkov 《Journal of the American Ceramic Society》2015,98(10):3223-3230
CaGd2(MoO4)4:Er3+/Yb3+ phosphors with the doping concentrations of Er3+ and Yb3+ (x = Er3+ + Yb3+, Er3+ = 0.05, 0.1, 0.2, and Yb3+ = 0.2, 0.45) have been successfully synthesized by the microwave sol–gel method, and the crystal structure refinement and upconversion photoluminescence properties have been investigated. The synthesized particles, being formed after heat‐treatment at 900°C for 16 h, showed a well‐crystallized morphology. Under the excitation at 980 nm, CaGd2(MoO4)4:Er3+/Yb3+ particles exhibited strong 525 and 550‐nm emission bands in the green region and a weak 655‐nm emission band in the red region. The Raman spectrum of undoped CaGd2(MoO4)4 revealed about 15 narrow lines. The strongest band observed at 903 cm?1 was assigned to the ν1 symmetric stretching vibration of MoO4 tetrahedrons. The spectra of the samples doped with Er and Yb obtained under 514.5 nm excitation were dominated by Er3+ luminescence preventing the recording Raman spectra of these samples. Concentration quenching of the erbium luminescence at 2H11/2→4I15/2 and 4S3/2→4I15/2 transitions in the CaGd2(MoO4)4:Er3+/Yb3+ crystal structure was established to be approximately at the 10 at.% doping level. 相似文献
8.
9.
Jiwon Lee Bryan S. Der Christos S. Karamitros Wenzong Li Nicholas M. Marshall Oana I. Lungu Aleksandr E. Miklos Jianqing Xu Tae Hyun Kang Chang-Han Lee Bing Tan Randall A. Hughes Sang Taek Jung Gregory C. Ippolito Jeffrey J. Gray Yan Zhang Brian Kuhlman George Georgiou Andrew D. Ellington 《American Institute of Chemical Engineers》2020,66(3):e16864
We used the molecular modeling program Rosetta to identify clusters of amino acid substitutions in antibody fragments (scFvs and scAbs) that improve global protein stability and resistance to thermal deactivation. Using this methodology, we increased the melting temperature (Tm) and resistance to heat treatment of an antibody fragment that binds to the Clostridium botulinum hemagglutinin protein (anti-HA33). Two designed antibody fragment variants with two amino acid replacement clusters, designed to stabilize local regions, were shown to have both higher Tm compared to the parental scFv and importantly to retain full antigen binding activity after 2 hr of incubation at 70°C. The crystal structure of one thermostabilized scFv variants was solved at 1.6 Å and shown to be in close agreement with the RosettaAntibody model prediction. 相似文献
10.
Aleksandr S. Kazachenko Feride Akman Natalya Yu. Vasilieva Noureddine Issaoui Yuriy N. Malyar Aleksandr A. Kondrasenko Valentina S. Borovkova Angelina V. Miroshnikova Anna S. Kazachenko Omar Al-Dossary Marek J. Wojcik Yaroslava D. Berezhnaya Evgeniy V. Elsufev 《International journal of molecular sciences》2022,23(3)
Betulin is an important triterpenoid substance isolated from birch bark, which, together with its sulfates, exhibits important bioactive properties. We report on a newly developed method of betulin sulfation with sulfamic acid in pyridine in the presence of an Amberlyst®15 solid acid catalyst. It has been shown that this catalyst remains stable when being repeatedly (up to four cycles) used and ensures obtaining of sulfated betulin with a sulfur content of ~10%. The introduction of the sulfate group into the betulin molecule has been proven by Fourier-transform infrared, ultraviolet-visible, and nuclear magnetic resonance spectroscopy. The Fourier-transform infrared (FTIR) spectra contain absorption bands at 1249 and 835–841 cm−1; in the UV spectra, the peak intensity decreases; and, in the nuclear magnetic resonance (NMR) spectra, of betulin disulfate, carbons С3 and С28 are completely shifted to the weak-field region (to 88.21 and 67.32 ppm, respectively) with respect to betulin. Using the potentiometric titration method, the product of acidity constants K1 and K2 of a solution of the betulin disulfate H+ form has been found to be 3.86 × 10–6 ± 0.004. It has been demonstrated by the thermal analysis that betulin and the betulin disulfate sodium salt are stable at temperatures of up to 240 and 220 °C, respectively. The density functional theory method has been used to obtain data on the most stable conformations, molecular electrostatic potential, frontier molecular orbitals, and mulliken atomic charges of betulin and betulin disulfate and to calculate the spectral characteristics of initial and sulfated betulin, which agree well with the experimental data. 相似文献