全文获取类型
收费全文 | 2741篇 |
免费 | 72篇 |
国内免费 | 9篇 |
专业分类
电工技术 | 117篇 |
综合类 | 2篇 |
化学工业 | 829篇 |
金属工艺 | 107篇 |
机械仪表 | 57篇 |
建筑科学 | 69篇 |
矿业工程 | 3篇 |
能源动力 | 110篇 |
轻工业 | 285篇 |
水利工程 | 9篇 |
石油天然气 | 4篇 |
武器工业 | 1篇 |
无线电 | 137篇 |
一般工业技术 | 564篇 |
冶金工业 | 214篇 |
原子能技术 | 70篇 |
自动化技术 | 244篇 |
出版年
2023年 | 11篇 |
2022年 | 43篇 |
2021年 | 53篇 |
2020年 | 28篇 |
2019年 | 41篇 |
2018年 | 50篇 |
2017年 | 39篇 |
2016年 | 53篇 |
2015年 | 46篇 |
2014年 | 72篇 |
2013年 | 153篇 |
2012年 | 121篇 |
2011年 | 154篇 |
2010年 | 135篇 |
2009年 | 142篇 |
2008年 | 139篇 |
2007年 | 133篇 |
2006年 | 120篇 |
2005年 | 92篇 |
2004年 | 109篇 |
2003年 | 94篇 |
2002年 | 78篇 |
2001年 | 52篇 |
2000年 | 49篇 |
1999年 | 51篇 |
1998年 | 76篇 |
1997年 | 58篇 |
1996年 | 50篇 |
1995年 | 41篇 |
1994年 | 42篇 |
1993年 | 37篇 |
1992年 | 34篇 |
1991年 | 35篇 |
1990年 | 26篇 |
1989年 | 33篇 |
1988年 | 20篇 |
1987年 | 29篇 |
1986年 | 28篇 |
1985年 | 24篇 |
1984年 | 21篇 |
1983年 | 16篇 |
1982年 | 25篇 |
1981年 | 20篇 |
1980年 | 22篇 |
1979年 | 23篇 |
1978年 | 11篇 |
1977年 | 17篇 |
1976年 | 19篇 |
1974年 | 14篇 |
1972年 | 8篇 |
排序方式: 共有2822条查询结果,搜索用时 15 毫秒
1.
Masahiro Sato Miyu Koriyama Satoshi Watanabe Masato Ohtsuka Takayuki Sakurai Emi Inada Issei Saitoh Shingo Nakamura Kazuchika Miyoshi 《International journal of molecular sciences》2015,16(8):17838-17856
Some reports demonstrated successful genome editing in pigs by one-step zygote microinjection of mRNA of CRISPR/Cas9-related components. Given the relatively long gestation periods and the high cost of housing, the establishment of a single blastocyst-based assay for rapid optimization of the above system is required. As a proof-of-concept, we attempted to disrupt a gene (GGTA1) encoding the α-1,3-galactosyltransferase that synthesizes the α-Gal epitope using parthenogenetically activated porcine oocytes. The lack of α-Gal epitope expression can be monitored by staining with fluorescently labeled isolectin BS-I-B4 (IB4), which binds specifically to the α-Gal epitope. When oocytes were injected with guide RNA specific to GGTA1 together with enhanced green fluorescent protein (EGFP) and human Cas9 mRNAs, 65% (24/37) of the developing blastocysts exhibited green fluorescence, although almost all (96%, 23/24) showed a mosaic fluorescent pattern. Staining with IB4 revealed that the green fluorescent area often had a reduced binding activity to IB4. Of the 16 samples tested, six (five fluorescent and one non-fluorescent blastocysts) had indel mutations, suggesting a correlation between EGFP expression and mutation induction. Furthermore, it is suggested that zygote microinjection of mRNAs might lead to the production of piglets with cells harboring various mutation types. 相似文献
2.
Tomoya Suzuki Kento Shiota Yu-ichiro Izato Masahiro Komori Koichi Sato Yasuyuki Takai Takayuki Ninomiya Atsumi Miyake 《International Journal of Hydrogen Energy》2021,46(11):8329-8343
Although hydrogen refueling stations (HRSs) are becoming widespread across Japan and are essential for the operation of fuel cell vehicles, they present potential hazards. A large number of accidents such as explosions or fires have been reported, rendering it necessary to conduct a number of qualitative and quantitative risk assessments for HRSs. Current safety codes and technical standards related to Japanese HRSs have been established based on the results of a qualitative risk assessment and quantitative effectiveness validation of safety measures over ten years ago. In the last decade, there has been much development in the technologies of the components or facilities used in domestic HRSs and much operational experience as well as knowledge to use hydrogen in HRSs safely have been gained through years of commercial operation. The purpose of the present study is to conduct a quantitative risk assessment (QRA) of the latest HRS model representing Japanese HRSs with the most current information and to identify the most significant scenarios that pose the greatest risks to the physical surroundings in the HRS model. The results of the QRA show that the risk contours of 10?3 and 10?4 per year were confined within the HRS boundaries, whereas the risk contours of 10?5 and 10?6 per year are still present outside the HRS. Comparing the breakdown of the individual risks (IRs) at the risk ranking points, we conclude that the risk of jet fire demonstrates the highest contribution to the risks at all of the risk ranking points and outside the station. To reduce these risks and confine the risk contour of 10?6 per year within the HRS boundaries, it is necessary to consider risk mitigation measures for jet fires. 相似文献
3.
4.
Peter V. Sushko Alexander L. ShlugerKatsuro Hayashi Masahiro HiranoHideo Hosono 《Thin solid films》2003,445(2):161-167
Recently it has been discovered that a nano-porous main group oxide 12CaO·7Al2O3 (C12A7) can be converted from a wide-gap insulator to a good transparent conductor. Using ab initio modelling we explain good conductivity of this material by very small barriers for hopping of localised electrons between neighbouring positive cages. We show that optical absorption of C12A7 in infrared region and at energies higher than 2.7 eV is due to inter-cage and intra-cage electron transitions, respectively. The proposed mechanisms can be useful in further search for conducting transparent media. 相似文献
5.
6.
We study theoretically the effect of the quasiparticle scattering in field-induced spin density waves (FISDW) in Bechgaard salts in a high magnetic field. The effects of scattering are introduced by a random impurity model similar to the one used by Zittartz in his analysis of the charge density wave. Within the single-gap approximation and weak impurity scattering, we find that the FISDW with normal impurities is similar to a superconductor with magnetic impurities. From this analogy the thermodynamics as well as the electronic thermal conductivity and the sound attenuation coefficient of the FISDW are obtained.On leave of absence from Nankai University, China. 相似文献
7.
Kenji Nomura Hiromichi OhtaKazushige Ueda Toshio Kamiya Masahiro HiranoHideo Hosono 《Thin solid films》2003,445(2):322-326
We have investigated the characteristics of transparent metal-insulator-semiconductor field-effect transistors (MISFETs) fabricated using InGaO3(ZnO)m (m=integer) single-crystalline thin films as n-channel layers and amorphous alumina as gate insulator films. The MISFETs exhibit good characteristics such as insensitivity to visible light illumination, off-current as low as ∼1 nA with a positive threshold voltage of ∼3 V and on/off current ratio of 105. The field-effect mobility increased from ∼1 to ∼10 cm2 (V s)−1 as the m-value increased. Room temperature Hall mobility also increased. However, unexpectedly these values were lower than the field-effect mobility. It is explained by existence of shallow localized state in the homologous compounds. 相似文献
8.
Masahiro Asari Shinichi Iwamoto Tatsuki Okamoto Hiromasu Fukagawa 《Electrical Engineering in Japan》1992,112(1):25-38
The recent increase in the demand for power in urban areas has caused changes in the way power is supplied. Underground distribution systems have been introduced for convenience in urban areas and to prevent injuries in case of a crisis. As a result, many new types of power cables are being used. One type, XPLE cables (also called CV cables) have been rapidly taking the place of conventional cables such as OF or SL cables since the 1960s because of their relatively easy installation and maintainability. However, distribution cables used under severe environmental conditions deteriorate rapidly (due mainly to water treeing), and some cables experience insulation breakdown. Therefore, many diagnostic methods have been developed, though they have not been very effective. By combining methods, a high reliability can be achieved in comparison to the use of a single method. However, processing the data is difficult for on-site personnel, so many experts are required. But there is a lack of qualified experts, hence we have turned to the development of expert systems. 相似文献
9.
Hirokazu Ikeda Chikara Fukunaga Yutaka Saitoh Masahiro Inoue Junko Yamanaka 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1996,380(3):618-622
The radiation tolerance for prototype front-end chips designed for a silicon micro-strip detector was examined with a 60Co irradiation source to establish an allowable range of the radiation dose. The irradiated front-end chips were SMA2SH-64A, a 64-channel preamplifier array; SMA2SH-1, a single-channel preamplifier circuit with a comparator; and Control-C, a digital-control chip for the preamplifiers. 相似文献
10.
Ti wire electrodes were immersed in acidic solutions containing H2SO4 and HCl of various concentrations at 353 K to evaluate corrosion rate by measurement of electric resistance change (resistometry). Addition of hydrochloric acid to sulphuric acid solution promoted depassivation of Ti. After depassivation, the immersion potential dropped to the hydrogen evolution potential and a hydride layer was formed on the surface. The hydride layer dissolved continuously in the acidic solution. SEM observation showed that Ti wires dissolved almost uniformly in the early stage and that the dissolution then trace became irregular due to nonuniform growth of the hydride layer. Dissolution rate of a Ti wire was estimated almost accurately by resistometry. 相似文献