全文获取类型
收费全文 | 929篇 |
免费 | 64篇 |
国内免费 | 27篇 |
专业分类
电工技术 | 102篇 |
综合类 | 60篇 |
化学工业 | 199篇 |
金属工艺 | 137篇 |
机械仪表 | 97篇 |
建筑科学 | 25篇 |
矿业工程 | 38篇 |
能源动力 | 26篇 |
轻工业 | 40篇 |
水利工程 | 14篇 |
石油天然气 | 16篇 |
武器工业 | 7篇 |
无线电 | 27篇 |
一般工业技术 | 82篇 |
冶金工业 | 28篇 |
原子能技术 | 2篇 |
自动化技术 | 120篇 |
出版年
2024年 | 8篇 |
2023年 | 8篇 |
2022年 | 8篇 |
2021年 | 26篇 |
2020年 | 20篇 |
2019年 | 18篇 |
2018年 | 13篇 |
2017年 | 21篇 |
2016年 | 20篇 |
2015年 | 18篇 |
2014年 | 58篇 |
2013年 | 47篇 |
2012年 | 59篇 |
2011年 | 63篇 |
2010年 | 41篇 |
2009年 | 61篇 |
2008年 | 41篇 |
2007年 | 63篇 |
2006年 | 71篇 |
2005年 | 44篇 |
2004年 | 59篇 |
2003年 | 39篇 |
2002年 | 36篇 |
2001年 | 32篇 |
2000年 | 26篇 |
1999年 | 25篇 |
1998年 | 12篇 |
1997年 | 10篇 |
1996年 | 5篇 |
1995年 | 16篇 |
1994年 | 16篇 |
1993年 | 10篇 |
1992年 | 8篇 |
1991年 | 9篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1986年 | 2篇 |
排序方式: 共有1020条查询结果,搜索用时 15 毫秒
71.
Eylem Turan 《Thin solid films》2010,518(21):5950-310
Thermoresponsive poly(N-isopropylacrylamide) [poly(NIPAM)] brush on silicon wafer surface was prepared by combining the self-assembled monolayer of initiator and atom transfer radical polymerization (ATRP). The resulting polymer brush was characterized by in situ reflectance Fourier transform infrared spectroscopy, atomic force microscopy and ellipsometry techniques. Gel permeation chromatography determination of the number-average molecular weight and polydispersity index of the brush detached from the silicon wafer surface suggested that the surface-initiated ATRP method can provide relatively homogeneous polymer brush. Contact angle measurements exhibited a two-stage increase upon heating over the board temperature range 25-45 °C, which is in contrast to the fact that free poly(NIPAM) homopolymer in aqueous solution exhibits a phase transition at ca. 34 °C within a narrow temperature range. The first de-wetting transition takes place at 27 °C, which can be tentatively attributed to the n-cluster induced collapse of the inner region of poly(NIPAM) brush close to the silicon surface; the second de-wetting transition occurs at 38 °C, which can be attributed to the outer region of poly(NIPAM) brush, possessing much lower chain density compared to that of the inner part. 相似文献
72.
文章在并行黑板模型基础的上,提出了将写生式分割策略用于桥梁目标识别的图象分割处理,基于该分割思想,我们在黑板模型试验床CPES上建立了问题求解模型,并进行了桥梁目标识别。 相似文献
73.
74.
The growth of the powder coating business is affected by the toxicological effects of the raw materials used in the coating formulation and the saturation of the present market for powder coatings, being limited to general metal applications only. This has a strong influence on the long-term research programmes at both raw materials suppliers and powder paint producers. In the last decade of the 20th century, we witness appearance of several new types of toxicologically-safe powder coating systems on the commercial scale. At the same time, there is strong evidence of efforts to penetrate new market fields where powder coatings are not typically used. This includes the markets for automotive clear top coatings, can and coil coatings, coatings for industrial wood, plastics and paper. The new developments in the chemistry of powder coatings are followed by changes and improvements in the production technology for powder coatings as well as developments of new application techniques. This paper summarises the research work on chemistry, production and application technology of powder coatings and tries to extrapolate the tendencies in the years to come in order to predict the achievements and the impacts on the paint industry. 相似文献
75.
A series of well-defined brush-type amphiphilic polystyrene-g-poly(2-(dimethylamino) ethyl methacrylate)) (PS-g-PDMAEMA) copolymers were successfully synthesized via atom transfer radical polymerization (ATRP), using chloromethylated polystyrene (CMPS) as the macroinitiator. The self-assembly behavior of the resulting brush-type copolymers in deionized water and deionized water/acetone (v/v=2/3) mixture was studied by high performance particle sizer (HPPS). The results showed that the Z-average size of the micelles in deionized water increased with the increase of molecular weight of PDMAEMA, and the corresponding size was larger than that in mixed solvent of deionized water and acetone (v/v=2/3). The morphologies of the micelles self-assembled from PS-g-PDMAEMA in selective solvents were studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). When the micelles were prepared in water/acetone (v/v=2/3) mixture and cast them on a glass slide at different temperatures (from 50 up to 200 °C), the transformation of the morphologies of aggregates, from needle-like solid to microcubic particles, was observed using SEM. 相似文献
76.
Hidetaka Kawakita Hiroyasu Masunaga Kanako Nomura Kazuya Uezu Isamu Akiba Satoshi Tsuneda 《Journal of Porous Materials》2007,14(4):387-391
Protein adsorption was performed by a polymer brush prepared by atom-transfer radical polymerization (ATRP) to a porous inorganic
membrane. The porous inorganic membrane, Shirasu Porous Glass made from silica, was modified with a halogen-containing compound
to bind the active species for the polymerization. Glycidyl methacrylate was polymerized from the halogen compound by ATRP
for a prescribed time, and subsequently chemically modified. The progression of the chemical modification allowed the membrane
to lower the phosphate-buffer flux of the porous membrane due to the attachment of the polymer brush. Bovine serum albumin
(BSA), as a model protein, was adsorbed at 12 mg per gram of the membrane in permeating BSA solution through the polymer-brush-attached
porous membrane. 相似文献
77.
Haitao LUO Qiming WEI Yuxin LI Junlin LI Wei ZHANG Weijia ZHOU 《Frontiers of Mechanical Engineering》2023,18(2):16
To examine the environmental characteristics of the microgravity force and the weathered layer on an asteroid surface, a symmetric wheel brush asteroid sampler is proposed for the collection of particles on the asteroid surface. To study the influence of the wheel brush rotation speed on the sampling efficiency and the driving torque required for the wheel brush, the contact dynamics model between particles and sampling wheel brushes is established and a simulation and experimental verification of the sampling process are conducted. The parameter calibration of the sampled particles is studied first, and the calibrated particle parameters are used in the numerical simulation of the sampling process. The sampling results and the particle stream curves are obtained for the working conditions of different rotation speeds, and the effects of different parameter settings on the sampling efficiency are analyzed. In addition, a set of rotating symmetrical sampling wheel brush devices is built for the ground test, and the dynamic torque sensor is used to test the torque change of the wheel brush during the sampling process. The relationship between the speed of the wheel brush and the driving torque of the wheel brush motor is determined by comparing the simulation results with the test results. Results indicate that when the rotating speed of the wheel brush is faster, the sampling efficiency is higher, and the driving torque required for the sampling wheel brush is greater. Moreover, a numerical simulation analysis of the sampling process of the wheel brush sampler in a microgravity environment is conducted to determine the optimal speed condition, and the brushing test of the wheel brush sampler in the microgravity environment is verified with the drop tower method. This research proposes the structural optimization design and motor selection of a wheel brush asteroid sampler, which provides important reference value and engineering significance. 相似文献
78.
79.
80.
带钢表面附着的油污、铁粉和灰尘等只有通过清洗段才能彻底清除,因此清洗段是带钢处理线重要组成部分.物理清洗是较常用的清洗工艺,其采用水作为溶剂对带钢表面进行冲刷洗,在刷毛的机械作用下,刷去残留在带钢表面上的油污、铁粉.对物理清洗的刷洗设备的设计进行了阐述,介绍了刷洗设备的功能及结构,刷辊控制调节及冷却,最后介绍了刷洗设备的改进. 相似文献