全文获取类型
收费全文 | 1400篇 |
免费 | 65篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 16篇 |
综合类 | 1篇 |
化学工业 | 360篇 |
金属工艺 | 59篇 |
机械仪表 | 46篇 |
建筑科学 | 23篇 |
能源动力 | 74篇 |
轻工业 | 51篇 |
水利工程 | 12篇 |
石油天然气 | 3篇 |
无线电 | 233篇 |
一般工业技术 | 272篇 |
冶金工业 | 54篇 |
原子能技术 | 4篇 |
自动化技术 | 263篇 |
出版年
2024年 | 3篇 |
2023年 | 35篇 |
2022年 | 50篇 |
2021年 | 72篇 |
2020年 | 68篇 |
2019年 | 54篇 |
2018年 | 79篇 |
2017年 | 75篇 |
2016年 | 67篇 |
2015年 | 43篇 |
2014年 | 72篇 |
2013年 | 130篇 |
2012年 | 71篇 |
2011年 | 84篇 |
2010年 | 75篇 |
2009年 | 70篇 |
2008年 | 55篇 |
2007年 | 55篇 |
2006年 | 45篇 |
2005年 | 31篇 |
2004年 | 16篇 |
2003年 | 16篇 |
2002年 | 19篇 |
2001年 | 21篇 |
2000年 | 16篇 |
1999年 | 16篇 |
1998年 | 7篇 |
1997年 | 20篇 |
1996年 | 17篇 |
1995年 | 16篇 |
1994年 | 15篇 |
1993年 | 13篇 |
1992年 | 11篇 |
1991年 | 9篇 |
1990年 | 7篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1976年 | 1篇 |
排序方式: 共有1471条查询结果,搜索用时 15 毫秒
61.
Sanjeev K. Gupta Sanjay D. Gupta Himadri R. SoniVenu Mankad Prafulla K. Jha 《Materials Chemistry and Physics》2014
The present paper reports the structural, electronic, phonon and thermodynamical properties of some transition-metal nitrides (TMN: TiN, VN and CrN) by means of first-principles calculations. The computed equilibrium lattice constant and bulk modulus agree well with the available experimental and theoretical data. The electronic band structure and density of states calculations show metallic nature. The phonon frequencies are positive throughout the Brillouin zone for these compounds in rocksalt structure indicating dynamical stability. The calculated electron–phonon coupling constant λ and superconducting transition temperature agree reasonably well with the available experimental data. These compounds behave as a conventional phonon-mediated superconductor. Within the GGA and quasi-harmonic approximation, thermodynamical properties are also investigated. 相似文献
62.
Wireless Personal Communications - In this paper, we propose a smart and robust home security system. This is for intrusion detection along with a proprietary Android application. Intruder-Spi... 相似文献
63.
Metrology plays the key role as the engine of industrial revolution and growth of any country. It promotes global competence and confidence. With the advent of better quality products through metrological advancement, our industries can compete internationally and to overcome trade barriers/constraints and finally to achieve exports targets. This translates into growth of industries through rapid industrialization, economic growth and societal upliftment. The metrology requires continued and sustained efforts to cater the stakeholders’ demands for advancements in measurement technologies, standards and measurement techniques for more and more precise, reliable, reproducible and accurate measurements with improved measurement uncertainties. In this context, the recent revolutionary changes in redefinition of SI units based on fundamental constants were unanimously voted for adoption by world community during November 16, 2018, at Versailles, France, and implemented world over from May 20, 2019—the World Metrology Day. Therefore, it was considered appropriate to compile a brief status report and apprise the readers about these historical events. The present paper touches glimpse of some of these activities and describes the implications of these changes in our daily life. 相似文献
64.
65.
Semiconductors - In this work, drain current ID for 5-nm gate length with dual-material (DM) double-surrounding gate (DSG) inversion mode (IM) and junctionless (JL) silicon nanotube (SiNT) MOSFET... 相似文献
66.
In the current study, a combination of acrylic polyol (AP) and ester polyol (EP) were synthesized and reacted at variable ratios with hexamethylene diisocyanates and isophorone diisocyanates to prepare a transparent two-component polyurethane (PU) coating formulation. The formations of the polyol system, isocyanate system, and the PU systems were confirmed by 1H nuclear magnetic resonance and Fourier-transform infrared spectroscopy. Transparency of the coatings was examined using haze, and gloss measurement, which showed acrylic-ester-polyurethane (aePU-5 and aePU-6) have 91.5% and 91.8% transparency and gloss of 90.3 and 90.7 GU respectively. The thermal properties like Tg and the thermal stability of the coatings were verified using differential scanning calorimetry, and thermogravimetric analysis respectively which was found to increase with increasing EP content and decreasing AP content which may be ascribed to improved compatibility of copolymers, and homogeneity in PU along with enhanced crosslinking density. The degree of adhesion of coating with the substrate was validated from lap-shear, and cross-cut tape test which showed improved performance at AP:EP ratio of 60:40. The coatings were found to exhibit resistance toward pencil hardness with aePU-5 and aePU-6 having the optimum resistance of 9H. The surface morphology and topography were observed under scanning electron microscopy, and atomic force microscopy, respectively. The outcome confirms the higher smoothness of the surfaces subjected to the increase in EP content. The PU system with 40 wt% AP content and 60 wt% EP designated as aePU-5 was found to exhibit optimum performance. 相似文献
67.
Photonic Network Communications - Performance of underwater wireless optical communication (UWOC) with different vertical water channel conditions is experimentally analyzed. Experiment has been... 相似文献
68.
Pradum Pundlikrao Ige Rohit Ravindra Badgujar Pankaj Padmakar Nerkar Hitendra Shaligram Mahajan Raju Onkar Sonawane Sanjay Javarilal Surana 《Particulate Science and Technology》2018,36(5):583-591
Drug which shows extensive first pass effect is difficult task that, needs to be solved by formulators in the pharmaceutical science. The low oral bioavailability (49%) of flutamide may be due to poor wettability, low aqueous solubility and extensive first pass effect. The aim of present investigation was to prepare flutamide loaded microspheres and incorporate it into suppositories for rectal delivery to avoid first pass effect and enhance residence time. Flutamide loaded mucoadhesive microspheres of Ocimum Basilicum mucilage (OBM) were prepared using spray drying and characterized by percent production yield, encapsulation efficiency, particle size, zeta potential, polydispersity index, DSC, SEM, XRPD, in vitro drug release and stability studies. Moreover, ex vivo mucoadhesion was investigated using falling liquid film technique to determine the adhesion of microspheres to sheep rectal mucosa. The microspheres had nearly spherical shape and size about 2.53?μm. The encapsulation efficiency and mucoadhesion of optimized formulation MBF10 were found to be 69.6?±?2.3% and 89.01?±?2.18%, respectively. Percent CDR of optimized flutamide loaded mucoadhesive microspheres was found to be 88.7?±?1.3 at 7?h. In conclusion, OBM microparticles based suppository could be used to deliver drug through rectal delivery. 相似文献
69.
70.
Pramod N. Jagadale Shivaji R. Kulal Meghanath G. Joshi Pramod P. Jagtap Sanjay M. Khetre Sambhaji R. Bamane 《Materials Science-Poland》2013,31(2):269-275
Here we report a successful preparation of nanostructured calcium silicate by wet chemical approach. The synthesized sample was characterized by various physico-chemical methods. Thermal stability was investigated using thermo-gravimetric and differential thermal analysis (TG-DTA). Structural characterization of the sample was carried out by the X-ray diffraction technique (XRD) which confirmed its single phase hexagonal structure. Transmission electron microscopy (TEM) was used to study the nanostructure of the ceramics while homogeneous grain distribution was revealed by scanning electron microscopy studies (SEM). The elemental analysis data obtained from energy dispersive X-ray spectroscopy (EDAX) were in close agreement with the starting composition used for the synthesis. Superhydrophilic nature of CaSiO3 was investigated at room temperature by sessile drop technique. Effect of porous nanosized CaSiO3 on early adhesion and proliferation of human bone marrow mesenchymal stem cells (BMMSCs) and cord blood mesenchymal stem (CBMSCs) cells was measured in vitro. MTT cytotoxicity test and cell adhesion test showed that the material had good biocompatibility and promoted cell viability and cell proliferation. It has been stated that the cell viability and proliferation are significantly affected by time and concentration of CaSiO3. These findings indicate that the CaSiO3 ceramics has good biocompatibility and that it is promising as a biomaterial. 相似文献