全文获取类型
收费全文 | 257篇 |
免费 | 21篇 |
专业分类
化学工业 | 77篇 |
金属工艺 | 3篇 |
机械仪表 | 6篇 |
建筑科学 | 9篇 |
能源动力 | 10篇 |
轻工业 | 52篇 |
水利工程 | 3篇 |
石油天然气 | 2篇 |
无线电 | 16篇 |
一般工业技术 | 45篇 |
冶金工业 | 12篇 |
原子能技术 | 1篇 |
自动化技术 | 42篇 |
出版年
2024年 | 1篇 |
2023年 | 10篇 |
2022年 | 17篇 |
2021年 | 33篇 |
2020年 | 5篇 |
2019年 | 12篇 |
2018年 | 24篇 |
2017年 | 20篇 |
2016年 | 15篇 |
2015年 | 9篇 |
2014年 | 11篇 |
2013年 | 28篇 |
2012年 | 10篇 |
2011年 | 7篇 |
2010年 | 8篇 |
2009年 | 11篇 |
2008年 | 9篇 |
2007年 | 9篇 |
2006年 | 7篇 |
2005年 | 3篇 |
2004年 | 3篇 |
2003年 | 1篇 |
2002年 | 2篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有278条查询结果,搜索用时 0 毫秒
271.
A novel cuckoo search algorithm with adaptive discovery probability based on double Mersenne numbers
Reda Mohamed Elhosseini Mostafa Haikal Amira Badawy Mahmoud 《Neural computing & applications》2021,33(23):16377-16402
Neural Computing and Applications - Cuckoo search algorithm is one of the most prominent meta-heuristic optimization algorithms which is applied to various applications. The discovery probability... 相似文献
272.
de Jesus CG dos Santos V Canestraro CD Zucolotto V Fujiwara ST Gushikem Y Wohnrath K Pessoa CA 《Journal of nanoscience and nanotechnology》2011,11(4):3499-3508
Nanostructured films comprising a 3-n-propylpyridinium silsesquioxane polymer (designated as SiPy+Cl-) and copper (II) tetrasulfophthalocyanine (CuTsPc) were produced using the Layer-by-Layer technique (LbL). To our knowledge this is the first report on the use of silsesquioxane derivative polymers as building blocks for nanostructured thin films fabrication. Deposition of the multilayers were monitored by UV-Vis spectroscopy revealing the linear increment in the absorbance of the Q-band from CuTsPc at 617 nm with the number of SiPy+Cl-/CuTsPc or CuTsPc/SiPy+Cl-bilayers. FTIR analyses showed that specific interactions between SiPy+Cl- and CuTsPc occurred between SO3- groups of tetrasulfophthalocyanine and the pyridinium groups of the polycation. Morphological studies were carried out using the AFM technique, which showed that the roughness and thickness of the films increase with the number of bilayers. The films displayed electroactivity and were employed to detection of dopamine (DA) and ascorbic acid (AA) using cyclic voltammetry, at concentrations ranging from 1.96 x 10(-4) to 1.31 x 10(-3) molL(-1). The number and the sequence of bilayers deposition influenced the electrochemical response in presence of DA and AA. Using differential pulse technique, films comprising SiPy+/-/CuTsPc were able to distinguish between DA and ascorbic acid (AA), with a potential difference of approximately with 500 mV, in the concentration range of 9.0 x 10(-5) to 2.0 x 10(-4) molL(-1), in pH 3.0. 相似文献
273.
274.
275.
Nadeem Sayyed Abdul Hafeez Fahad A. Al-Abbasi Asma B Omer Shareefa A. AlGhamdi Amira M. Alghamdi Rayan A. Sheikh Imran Kazmi 《European Journal of Lipid Science and Technology》2023,125(9):2200205
Erucic acid is a single unsaturated fatty acid that falls under the omega-9 fatty acid family. It was suggested to treat Wistar rats with lipopolysaccharide (LPS)-induced memory impairment and minimize cognitive impairment. A total of 30 animals were randomized: group I was normally treated group, group II was administered with LPS, group III was treated with LPS along with erucic acid at the dose of 10 mg kg–1 p.o.–1, group IV was treated with LPS along with erucic acid at 20 mg kg–1 p.o.–1 and group V was the erucic acid per se group provided at the dose of 20 mg kg–1 p.o.–1 per se. Behavioral tests were evaluated by using the Morris water maze and Y-maze. Biochemical analysis including acetylcholine esterase (AChE), choline acetyltransferase (ChAT), glutathione (GSH), catalase activity (CAT), superoxide dismutase (SOD), and nitric oxide (NO) along with proinflammatory mediators tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), caspase 3, and neuroinflammatory biomarker (nuclear factor kappa B-NF-κB) were measured. Erucic acid produced substantial behavioral improvement in the Y-maze test, including spontaneous alterations and reduced latency time during acquisition, and a longer duration of time in the consolidation phase undergoing the MWM test. Furthermore, erucic acid improved the AChE, proinflammatory markers, and oxidative stress as well as restoring endogenous antioxidant levels, ChAT, caspase 3, and NF-κB levels. Erucic acid may be a therapeutic component for conditions related to memory disorders such as memory impairment, enhances memory functioning, and protects against neuronal damage. 相似文献
276.
Summary The solution copolymerization of acrylamide (AAm) with N-vinyl pyrrolidone (NVP) was investigated using azobisisobutyronitrile
(AIBN) as an initiator at 60°C. The study was performed by measuring the rate of the copolymerization reaction, the molecular
weights and by determining the monomer reactivity ratios. In addition, the thermal properties (thermal conductivity, thermal
diffusivity and volumetric heat capacity) of the resulted copolymers in aqueous solutions were investigated at various temperatures.
The kinetic results and the apparent reactivity ratios indicate that NVP is more reactive than AAm towards the copolymerization
process. The values of the thermal properties whowed that the behaviour of such parameters depend on the polymer concentration,
the temperatures and the content of vinyl pyrrolidone in the copolymeric chains. 相似文献
277.
Rayleigh waves in a half-space exhibiting generalized thermoelastic properties based on Green-Lindsay (G-L), Lord-Shulman (L-S), and classical dynamical coupled (C-D) theories are discussed. The phase velocity of Rayleigh waves in the previous three different theories has been obtained. A comparison is carried out between the phase velocities of Rayleigh waves, displacements, stresses, and temperature as calculated from the different theories of generalized thermoelasticity. The C-D theory is recovered as a special case. It appears, in particular, that the results obtained from G-L theory tend to those of L-S theory as the values of the two relaxation times become closer to each other. The second relaxation time is well pronounced when it becomes larger than the first one. Furthermore, it is found that the thermal relaxation times decrease the speed of the elastic waves and modify the phase velocities of the Rayleigh waves. The results obtained and the conclusions drawn are discussed numerically and illustrated graphically. Relevant results of previous investigations are deduced as special cases. 相似文献
278.
5 day-old golden hamster pups preoperatively were tested on a thermal gradient, subjected to bilateral or unilateral olfactory bulbectomy or control dorsal cortical removal, and then tested on Days 6–25. Locomotion and rectal or belly temperature were monitored throughout the 2-min test. Controls became quiescent in the hot end of the gradient on Days 5–7 but after Day 8 chose cooler regions and increased their activity. Both unilaterally and bilaterally bulbectomized Ss spent more time in the heat throughout testing, were less active, and allowed their temperature to rise more rapidly than controls. Percentage of time in the heat was elevated in all bulbectomized Ss although some retained the ability to make an olfactory discrimination. Enhanced thermal behavior is apparently not due to anosmia per se. Altered thermal perception or responsitivity may result from loss of "nonspecific" olfactory projections that normally would mature at the beginning of the 2nd week. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献