全文获取类型
收费全文 | 3560篇 |
免费 | 63篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 192篇 |
综合类 | 4篇 |
化学工业 | 696篇 |
金属工艺 | 69篇 |
机械仪表 | 109篇 |
建筑科学 | 67篇 |
矿业工程 | 4篇 |
能源动力 | 115篇 |
轻工业 | 312篇 |
水利工程 | 7篇 |
石油天然气 | 9篇 |
无线电 | 433篇 |
一般工业技术 | 568篇 |
冶金工业 | 750篇 |
原子能技术 | 126篇 |
自动化技术 | 167篇 |
出版年
2023年 | 17篇 |
2022年 | 25篇 |
2021年 | 52篇 |
2020年 | 22篇 |
2019年 | 39篇 |
2018年 | 45篇 |
2017年 | 52篇 |
2016年 | 51篇 |
2015年 | 35篇 |
2014年 | 62篇 |
2013年 | 150篇 |
2012年 | 105篇 |
2011年 | 136篇 |
2010年 | 110篇 |
2009年 | 95篇 |
2008年 | 128篇 |
2007年 | 109篇 |
2006年 | 105篇 |
2005年 | 114篇 |
2004年 | 99篇 |
2003年 | 120篇 |
2002年 | 108篇 |
2001年 | 78篇 |
2000年 | 62篇 |
1999年 | 94篇 |
1998年 | 332篇 |
1997年 | 200篇 |
1996年 | 143篇 |
1995年 | 122篇 |
1994年 | 92篇 |
1993年 | 85篇 |
1992年 | 58篇 |
1991年 | 43篇 |
1990年 | 44篇 |
1989年 | 39篇 |
1988年 | 45篇 |
1987年 | 39篇 |
1986年 | 42篇 |
1985年 | 33篇 |
1984年 | 28篇 |
1983年 | 36篇 |
1982年 | 28篇 |
1981年 | 29篇 |
1980年 | 26篇 |
1979年 | 23篇 |
1978年 | 16篇 |
1977年 | 31篇 |
1976年 | 38篇 |
1975年 | 11篇 |
1974年 | 6篇 |
排序方式: 共有3628条查询结果,搜索用时 46 毫秒
111.
Yukio Tachibana Shigeaki Nakagawa Takeshi Takeda Akio Saikusa Takayuki Furusawa Kuniyoshi Takamatsu Kazuhiro Sawa Tatsuo Iyoku 《Nuclear Engineering and Design》2003,224(2):1010-197
Safety demonstration tests using the High Temperature Engineering Test Reactor (HTTR) will be conducted for the purpose of demonstrating inherent safety features of High Temperature Gas-cooled Reactors (HTGRs) as well as providing the core and plant transient data for validation of HTGR safety analysis codes. The first phase safety demonstration test items include the reactivity insertion test and the coolant flow reduction test. In the reactivity insertion test, which is the control rod withdrawal test, one pair out of 16 pairs of control rods is withdrawn, simulating a reactivity insertion event. The coolant flow reduction test consists of the partial loss of coolant flow test and the gas circulators trip test. In the partial loss of coolant flow test, primary coolant flow rate is slightly reduced by control system. In the gas circulators trip test one and two out of three gas circulators are run down, simulating coolant flow reduction events. The gas circulators trip tests, in which position of control rods are kept unchanged, are simulation tests of anticipated transients without scram (ATWS). 相似文献
112.
KenjiYoshii AkioNakamura MasaichiroMizumaki NaoshiIkeda Jun'ichiroMizuki 《中国稀土学报(英文版)》2004,22(6):733-738
Magnetic properties were investigated for the rare-earth 3d-transition metal oxides with the perovskite structure. Intriguing magnetic phenomena were reviewed for a few systems:magnetization peak effect in the titanates, magnetization reversal in the chromites and metallic ferromagnetism in the cobahites. The results suggest an important role of the rare-earth ions for the magnetic properties of such complex oxides. 相似文献
113.
Akira Masutani Tony Roberts Bettina Schüller Akio Yasuda Akira Sakaigawa Graham Cross David Bloor 《Journal of the Society for Information Display》2004,12(3):301-307
Abstract— A novel preparation method for dichroic dye‐doped polymer‐dispersed liquid crystals has been developed. This was achieved by creating a porous polymer matrix first by washing out the liquid crystal from a polymer‐dispersed liquid crystal (PDLC), which is then refilled with dye‐doped liquid crystal. Optimizing the liquid crystal used in the refilling results in decreased turn‐on voltage and faster response time. Poster‐standard reflectivity and newspaper‐standard contrast was demonstrated with a 3.8‐in. QVGA reflective TFT display with a drive voltage of 10 V. 相似文献
114.
Spark-plasma sintering is employed to synthesize self-lubricating ZrO2(Y2O3) matrix composites with different additives of CaF2 and Ag as solid lubricants by tailoring the composition and by adjusting the sintering temperature. The friction and wear behavior of ZrO2(Y2O3) matrix composites have been investigated in dry sliding against an alumina ball from room temperature to 800 °C. The effective self-lubrication at different temperatures depends mainly on the content of various solid lubricants in the composites. The addition of 35 wt.% Ag and 30 wt.% CaF2 in the ZrO2(Y2O3) matrix can promote the formation of a well-covered lubricating film, and effectively reduce the friction and wear over the entire temperature range studied. The friction coefficients at low temperatures were at a minimum value for the composite containing 35 wt.% of silver. At this silver concentration, low and intermediate temperature lubricating properties are greatly improved without affecting high-temperature lubrication by the calcium fluoride in ZrO2(Y2O3) matrix composites. The worn surfaces and transfer films formed during wear process have been characterized to identify the synergistic lubrication behavior of CaF2 and Ag lubricants at different temperatures. 相似文献
115.
Contrast in the phase response of intermittent-contact atomic force microscopy (IC-AFM) reveals in-plane structural and mechanical properties of polymer monolayers. This result is unexpected, as IC-AFM has previously only been considered as a probe of out-of-plane properties. Until now, AFM measurements of nanoscale in-plane properties have employed contact mode techniques. In-plane property measurements are possible with intermittent contact AFM because there is a small but significant component of tip motion parallel to the sample surface. This in-plane component of tip displacement is virtually universal in AFM, implying that oscillating-tip techniques generally are sensitive to in-plane material properties. We present a simple Hertzian model of intermittent-contact AFM that includes such an in-plane displacement. 相似文献
116.
Aluminium bronzes have been used as high strength, corrosion and wear resistance alloys for many decades. However, the alloy has a narrow solidification range and a complex nature which has confined its use to a limited field of applications. Published data on the wear characteristics and the metallurgical nature of the alloy system is limited, leaving wide possibilities for research. In the work described in this paper a study has been made of the metallurgical and tribological characteristics of aluminium bronzes conforming to BS 1400 AB2 specification. A novel centrifugal casting technique using a bonded sand lining integrated into a standard rotating die was adapted to cast a series of test bushes. Mechanical and microscopic aspects are studied and an attempt is made to correlate the physical properties with the tribological behaviour of the bushes. The results show that the test behaviour of the test bush was in some respects better than that of commercially produced bushes made by forging techniques. Detrimental embrittlement, due to ‘self annealing’ is significantly reduced by the adoption of the novel centrifugal casting technique referred to above. 相似文献
117.
118.
Adhesion between polymer surface modified by graft polymerization and tissue during surgery using an ultrasonically activated scalpel device 下载免费PDF全文
Kwangwoo Nam Takuya Iwata Tsuyoshi Kimura Hiroki Ikake Shigeru Shimizu Toru Masuzawa Akio Kishida 《应用聚合物科学杂志》2014,131(20)
In the field of surgery, achieving adhesion between a polymer implant and tissue poses a challenge considering that suturing is not appropriate for the stability of such implants. An ultrasonically activated scalpel that generates heat by mechanical vibration and promotes adhesion between a polymer implant and native tissue by pressing the two materials together has very good potential for application in the field. To determine the type of polymer that is suitable for the purpose, we investigated polyethylene (PE) and polystyrene (PS) films, the surfaces of which were activated by corona discharge. Graft polymerization was then performed on the corona‐treated surfaces to vary their properties. The corona‐treated PE and PS films grafted with poly(acrylic acid), poly(methacrylic acid), poly(vinyl benzylacrylic acid), and poly(hydroxylethyl acrylate), respectively, adhered to the tissue when the ultrasonically activated scalpel was applied. The heat generated by the mechanical vibration and the applied pressure enabled the carboxyl or hydroxyl groups to bond with the proteins in the extracellular matrix. We therefore concluded that it was possible to integrate this technique in the development of new types of polymer devices that could be stably implanted in a living body. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40885. 相似文献
119.
Although numerous swarm robotic systems have already been developed, they have exhibited limited adaptability. This was partly because the previous researchers designed the control schemes on the basis of informational interaction, without considering the physical effects of the environment. To tackle this problem, we employ an unconventional approach: we design a control scheme for swarm robots based on their physical interaction in a hydrodynamic field, inspired by biological swarming. Through simulations using a smoothed particle hydrodynamics method, we show that the proposed control scheme allows agents to form an ordered swarm in response to their environment. 相似文献
120.
Stephen Matthew Lyth Huaiyu Shao Jianfeng Liu Kazunari Sasaki Etsuo Akiba 《International Journal of Hydrogen Energy》2014
Hydrogen storage is a crucial technology for the realization of a carbon-neutral society. However, few materials have been able to approach useful hydrogen storage capacity at reasonable temperatures and pressures. Graphene has an extremely high surface-area-to-weight ratio, is strong, cheap, chemically inert, and environmentally benign. As such it may be an ideal substrate for hydrogen storage. Here we present synthesis of graphene foam by combustion of sodium ethoxide. This technique is low-cost, scalable, and results in a three-dimensional graphene network with a surface area of more than 1200 m2/g. It is applied as a hydrogen storage material at liquid nitrogen temperature, with a capacity of 2.1 wt%. 相似文献