全文获取类型
收费全文 | 399篇 |
免费 | 15篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 32篇 |
化学工业 | 90篇 |
金属工艺 | 15篇 |
机械仪表 | 20篇 |
建筑科学 | 9篇 |
能源动力 | 9篇 |
轻工业 | 36篇 |
水利工程 | 4篇 |
无线电 | 19篇 |
一般工业技术 | 59篇 |
冶金工业 | 47篇 |
原子能技术 | 20篇 |
自动化技术 | 57篇 |
出版年
2023年 | 3篇 |
2022年 | 4篇 |
2021年 | 11篇 |
2020年 | 8篇 |
2019年 | 5篇 |
2018年 | 9篇 |
2017年 | 10篇 |
2016年 | 9篇 |
2015年 | 11篇 |
2014年 | 11篇 |
2013年 | 29篇 |
2012年 | 22篇 |
2011年 | 29篇 |
2010年 | 13篇 |
2009年 | 22篇 |
2008年 | 23篇 |
2007年 | 17篇 |
2006年 | 12篇 |
2005年 | 14篇 |
2004年 | 11篇 |
2003年 | 10篇 |
2002年 | 7篇 |
2001年 | 6篇 |
2000年 | 9篇 |
1999年 | 2篇 |
1998年 | 17篇 |
1997年 | 10篇 |
1996年 | 15篇 |
1995年 | 2篇 |
1994年 | 7篇 |
1993年 | 12篇 |
1992年 | 7篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1972年 | 1篇 |
排序方式: 共有417条查询结果,搜索用时 0 毫秒
41.
We investigated the prevalence of Salmonella in chicken meat from northern, central, and southern Japan. Between 2006 and 2008, 821 samples from these three regions were collected and examined. Salmonella isolates were detected in 164 (20.0%) of these samples, with 15 (10.0%) of 150, 113 (27.5%) of 411, and 36 (13.8%) of 260 recovered from the northern, central, and southern regions, respectively. We recovered 452 Salmonella isolates. From the isolates, 27 serovars were identified; the predominant serovars isolated were Salmonella Infantis (n=81), Salmonella Kalamu (n=56), and Salmonella Schwarzengrund (n=43). Of the 452 isolates, 443 (98.0%) were resistant to one or more antibiotics, and 221 (48.9%) showed multiple-antibiotic resistance, thereby implying that multiple-antibiotic resistant Salmonella organisms are widespread in chicken meat in Japan. Resistance to oxytetracycline was most common (72.6%), followed by dihydrostreptomycin (69.2%) and bicozamycin (49.1%). This study, the first to report Salmonella prevalence in chicken meat throughout Japan, could provide valuable data for monitoring and controlling Salmonella infection in the future. 相似文献
42.
Tetsuo Yamada Naoyuki Mizuhara Hisashi Yamamoto Masayuki Matsui 《Computers & Industrial Engineering》2009,56(3):1113-1125
For sustainable manufacturing, manufacturers should construct and design inverse manufacturing systems consisting of assembly and disassembly systems. The sorting process in the disassembly system is the first process of the whole inverse manufacturing system. Therefore, it can become a bottleneck and decrease the productivity of the whole inverse manufacturing systems.This study focuses on a disassembly system with reverse blocking in a sorting process [Yamada, T., & Matsui, M. (2003). Disassembly production systems and its design issues. Reprints of Japan Industrial Management Association, Spring meeting, Chofu, Japan, May, 144–145 (in Japanese)]. It generalizes the queuing model and discusses the performance of the disassembly system by mathematical and numerical analysis. First, the sorting process with reverse blocking is generally modeled as a queuing system. Next, the stationary state equations of the system are formulated, and the objective function is set as the throughput. Finally, the system performance is discussed by mathematical and numerical analysis in cases of a different number of stations and buffers, and also an example of the system design is shown and discussed in view of the busy rate, blocking probability and throughput. 相似文献
43.
Ismail Peng Hong Liem Naoyuki Takaki Hiroshi Sekimoto 《Progress in Nuclear Energy》2008,50(2-6):290-294
The performance of natural uranium and thorium-fueled fast breeder reactors (FBRs) for producing 233U fissile material, which does not exist in nature, is investigated. It is recognized that excess neutrons from FBRs with good neutron economic characteristics can be efficiently used for producing 233U. Two distinct metallic fuel pins, one with natural uranium and another with natural thorium, are loaded into a large sodium-cooled FBR. 233U and the associated-U isotopes are extracted from the thorium fuel pins. The FBR itself is self-sustained by plutonium produced in the uranium fuel pins. Under the equilibrium state, both uranium and thorium spent fuels are periodically discharged with a certain discharge rate and then separated. All discharged fission products are removed and all discharged actinides are returned to the FBRs except the discharged uranium utilized for fresh fuel of the other thorium-cycled reactors. 233U-production rate of the FBRs as a function of both the uranium–thorium fuel pins fraction in the core and the discharge fuel burnup is estimated. The result shows that larger fraction of uranium pins is better for the FBR criticality while larger fraction of thorium fuel pins and lower fuel burnup give higher 233U production rate. 相似文献
44.
Satoshi Ogasawara Naoyuki Yamagishi Hiroyuki Totsuka Hirofumi Akagi 《Electrical Engineering in Japan》1993,113(4):113-122
In general, diode rectifiers with electrolytic capacitors on the dc side have been used as dc power supplies for voltage-source inverters. Rectifiers of this type, however, cause many problems such as poor power factor and harmonics. Recently, voltage-source PWM rectifier-inverters have been studied to provide the following advantages: (1) harmonic-free on both ac sides; (2) unity power factor on the input ac side; (3) power flow of either direction or power regeneration; (4) reduction of the dc capacitor. However, it is difficult for a conventional voltage-source PWM rectifier-inverter to regulate the capacitor voltage on transient states because it has only a voltage feedback loop. This paper describes a voltage-source PWM rectifier-inverter with feedforward control of instantaneous power. Based on the pq theory, the instantaneous power which is calculated in the control circuit of the inverter is fed forward to the control circuit of the rectifier. The feedforward control of instantaneous power contributes greatly to sufficiently suppress voltage fluctuation of the dc capacitor on transient states. Transient characteristics are discussed, and some interesting experimental results of a laboratory model are shown. 相似文献
45.
S. Miya S. Muramatsu N. Kuze K. Nagase T. Iwabuchi A. Ichii M. Ozaki I. Shibasaki 《Journal of Electronic Materials》1996,25(3):415-420
InAs/AlGaAsSb deep quantum well was successfully formed on GaAs substrate and examined for two electron devices, Hall elements
(HEs), and field-effect transistors (FETs). With a thin buffer layer of 600 nm AIGaAsSb on GaAs substrate, we observed high
electron mobility more than 23000 cm2/Vs and extrinsic effective electron velocity of 2.2 x 107 cm/s for a 15 nm thick InAs channel at room temperature. AIGaAsSb lattice matched to InAs was discussed from the view points
of insulating property, carrier confinement, and oxidization rate. Reliability data good enough for practical use were also
obtained for HEs. We demonstrated AIGaAsSb as a promising buffer/barrier layers for InAs channel devices on GaAs substrate,
and we discussed the possible advantages of AIGaAsSb also for InGaAs FETs. 相似文献
46.
Stephen Naoyuki Matsuba 《Computers and the Humanities》1993,27(5-6):331-340
This article describes how linguistic analysis can be used to change the computer from being a generator of data that can be used to develop a critical analysis to being a tool that provides a means to explore the processes and inputs that generate different interpretations of literary works. Using Michael Gregory's Communication Linguistics model to analyze Shakespeare's Sonnet CXXX, we see how the linguistic structure of the poem allows for multiple readings of the text. The article goes on to describe how this kind of analysis can be extended by employing artificial intelligence as a means to explore the interaction between language and meaning.Stephen N. Matsuba is currently completing his doctorate in English at York University, Canada. 相似文献
47.
2-Carboxybenzaldehyde dehydrogenase from the phenanthrene-degrading bacterium Nocardioides sp. strain KP7 was purified and characterized. The purified enzyme had a molecular mass of 53 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and 205 kDa by gel filtration chromatography. Thus, the homotetramer of the 53-kDa subunit constituted an active enzyme. The apparent Km and kcat values of this enzyme for 2-carboxybenzaldehyde were 100 microM and 39 s(-1), respectively, and those for NAD+ were 83 microM and 32 s(-1), respectively. The structural gene for this enzyme was cloned and sequenced. The length of the gene was 1,455 bp. The nucleotide sequence of the 10,279 bp of DNA around the gene for 2-carboxybenzaldehyde dehydrogenase was also determined, and seven open reading frames were found in this DNA region. These were the genes for 1-hydroxy-2-naphthoate dioxygenase (phdI) and trans-2'-carboxybenzalpyruvate aldolase (phdJ), orf1, the gene for 2-carboxybenzaldehyde dehydrogenase (phdK), orf2/orf3, and orf4. The amino acid sequence of the orf1 product was similar to that of the aromatic hydrocarbon transporter gene (pcaK) in Pseudomonas putida PRS2000. The amino acid sequence of the orf4 product revealed a similarity to cytochrome P-450 proteins. The region between phdK and orf4 encoded orf2 and orf3 on different strands. The amino acid sequences of the orf2 and orf3 products exhibited no significant similarity to the reported sequences in protein databases. 相似文献
48.
Tomomichi Okano Naoyuki Egawa Masami Fujiwara Masahiro Fukuda 《Journal of the American Oil Chemists' Society》1996,73(1):31-37
Sodium α-sulfonated, fatty acid polyethylene glycol monoesters [C
m
H2m+1CH(SO3Na)COO(C2H4O)
n
H] and diesters [C
m
H2m+1CH(SO3Na)COO(C2H4O)
n
COCH(SO3Na)C
m
H2m+1], wherem=10–16 andn=1–35, were prepared by esterification of α-sulfonated, fatty acids with polyethylene glycols, followed by neutralization
with NaOH. Crude products were purified by reversed-phase column chromatography on an octadecyl-modified silica gel. Characteristic
solution behavior of these α-sulfonated fatty acid esters was, examined, and the following features were observed. All monoesters
prepared in this work had Krafft points below 0°C and also possessed good calcium stabilities. Critical micelle concentrations
of the monoesters increased monotonously, as a rule, with an increase in the number of oxyethylene units. These results suggest
that the polyethylene glycol residue of the monoester behaves as a hydrophile. On the other hand, diesters possessed high
water solubility, low foamability, and critical micelle concentrations that were lower by a factor of ten compared to those
of the monoesters. 相似文献
49.
To assess the frictional properties at the wedge of a toroidal field coil of a tokamak fusion reactor, friction tests were conducted using structural steel, JN2, against various materials in a vacuum at low temperatures under a normal load of 10 N and a peak-to-peak sliding amplitude of 100 μm. The temperature was mainly ≈ 5 K and the ambient pressure ≈ 10−3 Pa. The relationship between the frictional characteristics and the number of cycles depends on both the material combination and temperature. Two typical patterns of behaviour were observed at 5 K depending on the combination; fairly constant friction and very high and fluctuating friction. The high friction was caused by severe adhesion between surfaces. Temperature dependence of friction was also observed for JN2-copper. 相似文献
50.
S Ueda T Tanita Y Hoshikawa T Nishimura J Shibuya S Iwabuchi Y Asino S Ono K Koike S Fujimura 《Canadian Metallurgical Quarterly》1993,31(10):1220-1226
We performed unilateral pulmonary arterial occlusion test (UPAO) for the preoperative evaluation of lung function in patients undergoing lung resection. In this test, the main pulmonary artery of either side is occluded to simulate postoperative functional status. In order to evaluate the right ventricular hemodynamic function, we measured right ventricular ejection fraction (RVEF) and right ventricular end-diastolic volume index (RVEDVI) throughout UPAO by thermodilution method. We investigated the relationships between changes in right ventricular hemodynamic function and postoperative complications related to cardiac functions, namely arrhythmias or heart failure. Thirty-four patients without heart disease prior to lung resection were examined by UPAO, and RVEF and RVEDVI were measured. Analyses demonstrated that changes in RVEF were inversely correlated with changes in RVEDVI. In 6 cases, RVEDVI increased from control by over 20% during UPAO. All of these patients had postoperative cardiac complications. The hypothetical ventricular function curves showed a large increase in RVEDVI relative to right ventricular stroke work index (RVSWI), suggesting a decrease in right ventricular function. In conclusion, these results suggest that changes in RVEDVI during UPAO may predict postoperative cardiac complications in patients undergoing pulmonary resection. 相似文献