全文获取类型
收费全文 | 210篇 |
免费 | 25篇 |
专业分类
电工技术 | 7篇 |
化学工业 | 59篇 |
金属工艺 | 3篇 |
机械仪表 | 4篇 |
建筑科学 | 4篇 |
能源动力 | 29篇 |
轻工业 | 60篇 |
无线电 | 9篇 |
一般工业技术 | 29篇 |
冶金工业 | 6篇 |
原子能技术 | 1篇 |
自动化技术 | 24篇 |
出版年
2021年 | 12篇 |
2020年 | 14篇 |
2019年 | 10篇 |
2018年 | 16篇 |
2017年 | 9篇 |
2016年 | 14篇 |
2015年 | 14篇 |
2014年 | 16篇 |
2013年 | 30篇 |
2012年 | 11篇 |
2011年 | 9篇 |
2010年 | 13篇 |
2009年 | 8篇 |
2008年 | 3篇 |
2007年 | 11篇 |
2006年 | 7篇 |
2004年 | 3篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有235条查询结果,搜索用时 31 毫秒
41.
Design,Synthesis, and Evaluation of ω‐(Isothiocyanato)alkylphosphinates and Phosphine Oxides as Antiproliferative Agents 下载免费PDF全文
Łukasz Janczewski Dr. Mateusz Psurski Dr. Marta Świtalska Dr. Anna Gajda Dr. Tomasz M. Goszczyński Prof. Dr. Józef Oleksyszyn Prof. Dr. Joanna Wietrzyk Prof. Dr. Tadeusz Gajda 《ChemMedChem》2018,13(1):105-115
A series of 21 novel, structurally diverse ω‐(isothiocyanato)alkylphosphinates and phosphine oxides (ITCs) were designed and synthesized in moderate to good yields. The synthesized compounds were evaluated for in vitro antiproliferative activity using LoVo and LoVo/DX cancer cell lines. The biological activity of the synthesized compounds was higher than that of natural isothiocyanates such as benzyl isothiocyanate or sulforaphane. The antiproliferative activity of selected ITCs was also tested on selected cancer cell lines: A549, MESSA and MESSA/DX‐5, HL60 and HL60MX2, BALB/3T3, and 4T1. These compounds were assessed for their mechanism of action as inducers of cell‐cycle arrest and apoptosis. Ethyl (6‐isothiocyanatohexyl)(phenyl)phosphinate ( 71 ) was tested in vivo on the 4T1 cell line and demonstrated moderate antitumor activity, similar to that benzyl isothiocyanate and cyclophosphamide. 相似文献
42.
Rodríguez E Simoes RV Roig A Molins E Nedelko N Slawska-Waniewska A Aime S Arús C Cabañas ME Sanfeliu C Cerdán S García-Martín ML 《Magma (New York, N.Y.)》2007,20(1):27-37
A new iron-based T 1 contrast agent consisting of a complex of iron ions coordinated to phosphate and amine ligands (Fe(phos) in short) has been characterized by spectroscopic and magnetic measurements. NMR relaxation studies showed r 1 values to be dependent on the phosphate salt concentration, K2HPO4, present in the medium. r 1 reaches a maximum value of 2.5 mM?1 s?1 for measurements carried out at 7 T and 298 K. 31P MRS, Mössbauer spectroscopy and magnetic measurements of Fe(phos) solutions suggest paramagnetic Fe3+ ions present in the studied iron–phosphate complex. In vitro and in vivo toxicity experiments with C6 cells and CD1 mice, respectively, demonstrated lack of toxicity for Fe(phos) at the highest dose tested in the MRI experiments (12 mM iron for C6 cells and 0.32 mmol iron/kg for mice). Finally, T 1 weighted images of brain tumours in mice have shown positive contrast enhancement of Fe(phos) for tumour afflicted regions in the brain. 相似文献
43.
Anna Niemczyk Anna Olszewska Zhihong Du Zijia Zhang Konrad Świerczek Hailei Zhao 《International Journal of Hydrogen Energy》2018,43(32):15492-15504
In this paper, selected layered cuprates with La2-x(Sr,Ba)xCuO4-δ formula are evaluated as candidate cathode materials for Solid Oxide Fuel Cells. Two synthesis routes, a typical solid state reaction and a sol-gel method yield well-crystallized La1.5Sr0.5CuO4-δ, La1.6Ba0.4CuO4-δ and La1.5Sr0.3Ba0.2CuO4-δ materials having tetragonal I4/mmm space group, but differing in morphology of the powder. Fine powders obtained using sol-gel route seem to be more suitable for preparation of the porous cathode layers having good adhesion on the solid electrolyte, but powders obtained after the solid state route can be also successfully utilized. Investigations of structural and transport properties, the oxygen nonstoichiometry and its change with temperature, thermal expansion, as well as chemical and thermal stability are systematically performed, to evaluate and compare basic physicochemical properties of the oxides. At room temperature the average valence state of copper is found to be in 2.2–2.35 range, indicating oxygen deficiency in all of the compounds, which further increases with temperature. The conducted high-temperature X-ray diffraction tests reveal moderate, but anisotropic thermal expansion of La2-x(Sr,Ba)xCuO4-δ, with higher expansion at temperatures above 400 °C occurring along a-axis, due to the oxygen release. However, the corresponding chemical expansion effect is small and the materials possess moderate thermal expansion in the whole studied temperature range. All compounds show relatively high electrical conductivity at the elevated temperatures, related to the Cu2+/Cu3+ charge transfer, with the highest values recorded for La1.5Sr0.5CuO4-δ. Comprehensive studies of chemical stability of the selected La1.5Sr0.5CuO4-δ material with La0.8Sr0.2Ga0.8Mg0.2O3-δ solid electrolyte revealed complex behavior, with stability being dependent apart from temperature, also on morphology of the powders. A model describing such behavior is presented. While it is possible to minimize reactivity and characterize electrochemical properties of the La1.5Sr0.5CuO4-δ-based cathode layer, usage of the buffer layer is indispensable to maintain full stability. It is shown that mutual chemical compatibility of La1.5Sr0.5CuO4-δ and commonly used La0.4Ce0.6O2-δ buffer layer material is excellent, with no reactivity even at 1000 °C for prolonged time. Laboratory-scale fuel cell with the La1.5Sr0.5CuO4-δ cathode sintered at the optimized temperature is able to deliver 0.16 W cm?2 at 800 °C while fueled with wet hydrogen. 相似文献
44.
Marek Kułażyński Sławomir Jabłoński Jan Kaczmarczyk Łukasz Świątek Katarzyna Pstrowska Marcin Łukaszewicz 《能源学会志》2018,91(5):668-675
The technological problems occurring in the co-firing of biomass and brown coal (lignite) prompted this research project. During the fuel preparation, accidental self-ignition and explosions were several times reported by power plants operators. The aim of this study was to evaluate brown coal, sunflower husks and sunflower husk pellets as fuels for co-firing in energetic boilers. Sunflower husk had a lower ash content and calorific value than the pellets. The range of the combustion temperatures of the biomass (200–300 °C) was narrower than that of brown coal (200–800 °C). The formation of highly alkaline ash from the biomass resulted in the formation in boiler of agglomerates of ash. The elemental composition, thermogravimetric and biological analyses suggested that the pellets contained synthetic additives difficult to identify. The biological method was proposed for evaluating biomass additives. The use of additional agents in the pelletizing process may influence on the combustion parameters. Mixing biomass with brown coal may occasionally result in self-ignition in the logistic chain. Plastic additives and biological activity may contribute to self-ignition. 相似文献
45.
46.
In this article, the growing body of literature on transition within central and eastern Europe is developed by exploring how discussing the senses may illuminate the experience of change to post-socialism for urban dwellers. After situating the study within the rich ethnographic heritage on urban transition, the key tenets of ‘geographies of smell’ are outlined as a means of inquiry which emphasises the lived, sensually embodied experience of transition. The empirical study is focused upon the interrogation of the meanings created by, and attached to, olfactory experience in contemporary Poland, discussing three motifs that highlight the symbolic and transformative role of smell in relation to transition. In understanding smell as playing an active role in the creation of meaning, not only are current debates surrounding geographies of smell extended, but it is argued that addressing the relatively neglected sensual dimension of the social provides an avenue into more nuanced dimensions of urban transition. 相似文献
47.
During drying or desiccation of clay-type materials, some stresses appear. Usually they are compressional inside of the material and tensional close to the surface. If the tensional stresses exceed the material strength, the clay cracks. This article is devoted to the modeling and numerical simulation of this phenomenon. The proposed model consists of two parts. The mass transfer is described by a simple diffusion equation together with convective boundary conditions. In the mechanical part it is assumed that the clay is composed of small particles linked together by cohesive forces. These forces are described with the use of mesh models. Two models are proposed: elastic (mesh consists of springs) and viscoelastic one (mesh consists of Maxwell elements). Four types of clays were tested experimentally to obtain the model parameters. The tested materials were selected with respect to different mineralogical compositions that determine the water-bonding ability. Simulations of the convective drying of bricks made of these clays were performed. It was shown that the degree of cracking depends on the quartz content of the clay. The obtained results were compared with experimental ones and good agreement between simulations and experiment was obtained. Additionally, the inner forces caused by drying are analyzed and discussed in this work. 相似文献
48.
KRZYSZTOF CIEŚLICKI 《Chemical Engineering Communications》2013,200(1):67-81
Flow in a certain class of plane and axisymmetrical periodic channels have been theoretically and experimentally examined. The general properties of solution of the stationary Navier-Stokes equation in such flows have been formulated. The results of experiments have been analysed with help of the Forchheimer equation. Some general remarks on the Darcy law and the Forchheimer equation applicability basing on presented theory and visualization of examined flows have been also formulated. 相似文献
49.
Zbigniew Czech Agnieszka Kowalczyk Janina Kabatc Xi-Quan Cheng Jolanta Świderska 《Journal of Adhesion Science and Technology》2013,27(22):2398-2410
This study investigated the photocrosslinking of solvent-based acrylic pressure-sensitive adhesives (PSA) containing selected photoinitiators type I, known as α-cleavage photoinitiators. Photocrosslinking of PSA, especially of acrylic PSA, is well established crosslinking process using the UV radiation technology. UV-initiated crosslinking of acrylic PSA allows the synthesis of the wide range of UV-crosslinkable PSA with the interesting features. Especially, the important balances of properties such as adhesive and cohesive strength which are typically critical for the application performance can be achieved by this technology. The selection of suitable photoinitiator plays an important role to obtain the optimum properties of acrylic PSA including tack, peel adhesion, and shear strength. In this study, the investigations on different saturated conventional photoinitiators of type I for solvent-based PSA were carried out. The effects of photoinitiator concentration, UV crosslinking time and UV dose on the tack, peel strength, and shear strength were explored in detail for guiding the choice of photoinitiators to fabricate advanced PSA for industrial usage. 相似文献
50.