全文获取类型
收费全文 | 330篇 |
免费 | 16篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 20篇 |
化学工业 | 58篇 |
金属工艺 | 4篇 |
机械仪表 | 4篇 |
建筑科学 | 4篇 |
矿业工程 | 1篇 |
能源动力 | 16篇 |
轻工业 | 24篇 |
水利工程 | 2篇 |
无线电 | 30篇 |
一般工业技术 | 71篇 |
冶金工业 | 24篇 |
自动化技术 | 89篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 8篇 |
2021年 | 17篇 |
2020年 | 19篇 |
2019年 | 15篇 |
2018年 | 12篇 |
2017年 | 4篇 |
2016年 | 12篇 |
2015年 | 12篇 |
2014年 | 17篇 |
2013年 | 31篇 |
2012年 | 12篇 |
2011年 | 22篇 |
2010年 | 11篇 |
2009年 | 13篇 |
2008年 | 20篇 |
2007年 | 16篇 |
2006年 | 4篇 |
2005年 | 6篇 |
2004年 | 9篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 5篇 |
1997年 | 10篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1977年 | 7篇 |
1976年 | 2篇 |
1971年 | 2篇 |
1969年 | 1篇 |
排序方式: 共有347条查询结果,搜索用时 39 毫秒
221.
Three novel peptides, IQW, IRW and LKP, were predicted in our previous study in the thermolysin–pepsin ovotransferrin hydrolysate. The aims of the present study were to purify the peptides, and determine if the predicted peptides purified from the hydrolysate would have the same activity as the synthetic ones. We also determined the stability of the peptides under simulated gastrointestinal condition. IQW, IRW and LKP were then successfully purified from crude ovotransferrin hydrolysate through multi-step chromatographic purification comprising of cation exchange chromatography followed by three-step reverse-phase high performance liquid chromatography (RP-HPLC), and their sequences were analysed by UPLC-MS/MS. Our results showed that their activities were comparable to the synthetic ones. Simulated gastrointestinal incubation showed that IRW was degraded into a dipeptide of IR and a free amino acid of W by pancreatin, LKP was degraded into a dipeptide of KP and a free amino acid of L by mucosal peptidase, while IQW was stable against the digestive enzymes. 相似文献
222.
223.
A segmented silicon based multimode to dual port slot structure on silicon-on-insulator platform is proposed which can be used as a refractive-index sensing device. The introduction of segmentation leads to tuning the effective index of the device which results in increasing compactness of the sensing device. Although the structure supporting TM mode is more compact than TE mode, but TE mode is considered here as vertical slots in the output section enhances optical signal in the slots for TE mode only. By considering dual output, the device length is reduced further as dual self-imaging length is less compared to single self-imaging distance for symmetrical multimode section input. The surface sensitivity of the structure has a typical value of~2249?nm/RIU. Relative sensitivity can be calculated from the ratio of field amplitudes of the arms of the dual output. Matrix method and 2D FDTD is used for the entire analysis.? 相似文献
224.
Jens Fruhstorfer Cornelius Demuth Pitt Goetze Christos G. Aneziris Subhashis Ray Ulrich Gross Dimosthenis Trimis 《Journal of the European Ceramic Society》2018,38(1):303-312
This study investigates the particle size distribution's effect on the microstructure and effective thermal conductivity (ETC) of alumina castables. The ETC was measured by the transient plane source method and predicted numerically based on a two-scale model describing the structure on a fine and coarse scale. The prediction considered particle and pore size distributions, porosity (around 20%) and grain morphology. The microstructure was investigated by scanning electron microscopy. For a constant fines content, increasing the coarse grain fraction while decreasing the medium fraction enhanced sintering of the matrix. Small pores (≤250 nm) increased the sintering activity. The densest castable contained the most small pores. The particles’ and pores’ contributions to the sintering activity led to intensified microcracking and a decreased ETC. The numerical model did not consider constituents ≤500 nm like the small pores and microcracks and the calculated ETC values consequently deviated from the measured values. 相似文献
225.
226.
227.
Egg ovotransferrin‐derived ACE inhibitory peptide IRW increases ACE2 but decreases proinflammatory genes expression in mesenteric artery of spontaneously hypertensive rats
下载免费PDF全文
![点击此处可从《Molecular nutrition & food research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
228.
Sabapathy Manigandan Saptarshi Majumder Saibal Ganguly Kajari Kargupta 《Materials Letters》2008,62(17-18):2758-2761
We present the formation of nano-structures especially nano-rod and nano-particles of polyaniline (PANI) using Langmuir–Blodgett (LB) technique of molecular deposition. Decrease in the pH of the sub-phase of LB trough increases level of doping (protonation) of polyaniline emeraldine base to emeraldine salt and causes doping induced nano-structure formation. High resolution transmission electron microscopy reveals that anisotropic rod like nano-structures of PANI of diameter less than 50 nm are formed at pH 1 while pH 3 induces the formation of dispersed nano-particle of diameter 15 nm. On the contrary, connected lump (aggregation) type nano-structures of PANI are formed at a higher value of pH 6. 相似文献
229.
H Seo M Yamagishi SA Haque AK Mohibullah Majumder A al-S S Nakatani OL Kwan AN DeMaria K Miyatake 《Canadian Metallurgical Quarterly》1997,61(11):905-911
An enhanced method for determining cardiac output using Doppler color flow imaging techniques to measure mitral orifice diameter was developed and validated in an experimental model and in clinical patients. In an in vitro circuit model, color jet width correlated well with actual orifice dimension from 12 to 24 mm (r = 0.99). In the clinical application, mitral valve area was calculated as a X b X pi/4 where a and b represent the width of the color flow stream in the mitral orifice just distal to the annulus in apical long-axis (short-diameter) and 4-chamber (90 degrees rotated, long-diameter) views, respectively. Cardiac output was then computed as the product of mitral valve area and time-velocity integral of transmitral flow from the same site. Cardiac output was also measured by thermodilution and conventional echocardiographic methods using diameters and time-velocity integrals from the left ventricular outflow tract. In 30 patients with nonvalvular heart disease, cardiac output measured by thermodilution ranged from 3.40 to 8.40 L/min. Cardiac output was determined in 28 of 30 patients (93%) by the Doppler color flow imaging technique; it ranged from 3.00 to 8.36 L/min and correlated well with thermodilution: y = 0.90x + 0.63, r = 0.91. Cardiac output was determined in 24 of 30 patients by the conventional left ventricular outflow method (80%). The cardiac output measured by the conventional method correlated less closely with thermodilution (r = 0.84), although there was no statistical difference in correlation coefficiencies between the 2 methods. These results indicate that the Doppler color flow imaging technique can be used to enhance the determination of cardiac output by echocardiography, particularly when the conventional method has resulted in technically inadequate recordings. 相似文献
230.
Summary This paper addresses the issue of anisotropy in overall thermal conductivity of a shape memory alloy microstructure that is
single crystalline in the high temperature austenitic state. The Voigt and Reuss bounds of the thermal conductivity are given.
It is shown that the trace of the Voigt bound is independent of the specific variants that may exist and their orientations
in the microstructure, whereas it is not so for the Reuss bound. It is also shown that both bounds of a purely self-accomodated
martensitic microstructure originating from a cubic parent phase are isotropic and independent of the geometric properties
of the variants. The bounds are then applied to the study of orthorhombic martensitic SMAs that are single crystalline in
the cubic austenitic state. Using the resolved shear stress approach for variant selection, the impact of anisotropy in the
thermal conductivity components of the orthorhombic martensite is studied for a single variant microstructure where the Voigt
and Reuss bounds are used as estimates for the thermal conductivity of a cylindrical domain. Their impact on the normalized
average steady state temperature and the normalized time taken to attain steady state are studied. This work is the precursor
of experimental research on the anisotropy in thermal conductivity of shape memory alloys, of which virtually none exists
in the open literature today. 相似文献