全文获取类型
收费全文 | 1133篇 |
免费 | 20篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 66篇 |
综合类 | 2篇 |
化学工业 | 272篇 |
金属工艺 | 47篇 |
机械仪表 | 27篇 |
建筑科学 | 15篇 |
能源动力 | 38篇 |
轻工业 | 60篇 |
水利工程 | 1篇 |
无线电 | 125篇 |
一般工业技术 | 194篇 |
冶金工业 | 170篇 |
原子能技术 | 44篇 |
自动化技术 | 97篇 |
出版年
2023年 | 7篇 |
2022年 | 16篇 |
2021年 | 26篇 |
2020年 | 10篇 |
2019年 | 12篇 |
2018年 | 18篇 |
2017年 | 14篇 |
2016年 | 20篇 |
2015年 | 7篇 |
2014年 | 33篇 |
2013年 | 59篇 |
2012年 | 41篇 |
2011年 | 57篇 |
2010年 | 56篇 |
2009年 | 46篇 |
2008年 | 54篇 |
2007年 | 38篇 |
2006年 | 46篇 |
2005年 | 28篇 |
2004年 | 23篇 |
2003年 | 32篇 |
2002年 | 28篇 |
2001年 | 23篇 |
2000年 | 16篇 |
1999年 | 44篇 |
1998年 | 72篇 |
1997年 | 43篇 |
1996年 | 34篇 |
1995年 | 36篇 |
1994年 | 27篇 |
1993年 | 26篇 |
1992年 | 13篇 |
1991年 | 10篇 |
1990年 | 13篇 |
1989年 | 9篇 |
1988年 | 4篇 |
1987年 | 5篇 |
1986年 | 6篇 |
1985年 | 14篇 |
1984年 | 8篇 |
1983年 | 6篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 11篇 |
1979年 | 10篇 |
1978年 | 10篇 |
1977年 | 15篇 |
1976年 | 12篇 |
1967年 | 2篇 |
1963年 | 2篇 |
排序方式: 共有1158条查询结果,搜索用时 15 毫秒
1.
Tsuchiya Letícia Diniz Braga Lucas Fiorini de Faria Oliveira Otávio de Bettio Raphael Winckler Greghi Juliana Galvani Freire André Pimenta 《Personal and Ubiquitous Computing》2021,25(2):281-295
Personal and Ubiquitous Computing - This article presents a study concerning the evaluation of a smart home control system for elderly people with a sample of 10 users in a city in the interior of... 相似文献
2.
Masatsune Kato Takaaki Aoki Takashi Noji Yasuhiro Ono Yoji Koike Tomoyuki Hikita Yoshitami Saito 《Journal of Superconductivity and Novel Magnetism》1994,7(1):37-38
We have investigated the relation between the crystal structure and superconductivity in La1.9Bi0.1CuO4+δ , in which the phase separation observed in La2CuO4+δ is suppressed. A phase diagram in theT?δ plane is given for La1.9Bi0.1CuO4+δ with excess oxygen. For very smallδ values, the crystal structure is orthorhombic, and an orthorhombic-tetragonal phase transition occurs markedly atδ ~ 0.03 in the measured temperature range between 13 and 293 K. Superconductivity is observed in the range of 0.04<δ<0.11. This is clear evidence thathigh-T c superconductivity also appears in the tetragonal phase. 相似文献
3.
T Kuroda T Shimamoto T Mizushima T Tsuchiya 《Canadian Metallurgical Quarterly》1997,179(23):7600-7602
The activity of the NhaA Na+/H+ antiporter of Vibrio parahaemolyticus is inhibited by amiloride. We found an amino acid sequence in the NhaA that was identical to a putative amiloride binding domain of the Na+/H+ exchanger in mammalian cells. We constructed mutant NhaAs that had amino acid substitutions in the putative amiloride binding domain by site-directed mutagenesis. These include V62L (Val62 replaced by Leu), F63Y, F64Y, and L65F. Most mutant NhaAs showed decreased sensitivity for amiloride. Among these, the F64Y mutant NhaA showed the least amiloride sensitivity, with a Ki value 7 to 10 times greater than that in the wild type. Thus, the sequence between residues V62 and L65 in NhaA, especially F64, is very important for the inhibitory effect of amiloride on the antiporter. 相似文献
4.
Tadashi Hano Michiaki Matsumoto Takahisa Kawazu Takaaki Ohtake 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1995,62(1):60-63
The extraction equilibria of various di- and tripeptides with di-2-ethylhexylphosphoric acid (D2EHPA) were studied at low pH values. The complex extracted to organic phase consisted of one molecule of peptide and two molecules of D2EHPA dimer. The extraction constants of the peptides correlated well with the distribution coefficients of peptides between 1-octanol and water, which is a measure of hydrophobicity. The permeation rates of peptides through an emulsion liquid membrane were examined by using D2EHPA as a carrier, Span 80 as an emulsifier and kerosene as a diluent. The rates varied considerably with peptide type, depending upon the hydrophobicity. 相似文献
5.
A 66-kV network generally is grounded through a neutral grounding resistor. In this network a single-phase ground-fault current is limited to as small as 100 to 400 A. There are parallel four-circuit transmission lines mounted on the same tower in the 66-kV network. In such transmission lines, the load and the fault currents could induce circulating current that flows through the lines. Since the circulating current has zero-phase-sequence and negative-phase-sequence components, it could cause unwanted operation of a balance ground relay using zero-phase-sequence current. However, it is difficult to compensate for the circulating current by the conventional vector compensation scheme. This paper presents a new balance ground relay to deal with the circulating current. In the relay from the ground-fault inception until first tripping, the difference current Δ3I2d of negative-phase-sequence current 3I2d of the differential current between two protected lines is used as an input current. The Δ3I2d is the difference current of 3I2d between, before and during faults. After the first tripping, the difference current of positive-phase-sequence load current and zero-phase-sequence current of the forementioned differential current are used as an input current. Consequently, a higher sensitivity of the ground-fault protection for these lines has been achieved. The correct operation of the new balance ground relay was confirmed when a single-phase-ground-fault occurred in the parallel four-circuit transmission lines, to which the relay is applied. 相似文献
6.
Hot-carrier degradation of lightly doped drain (LDD) MOSFET's under ac stress is investigated. Enhanced ac degradation occurs in LDD MOSFET's as well as in single-drain MOSFET's. However, there is a peculiar degradation mechanism in LDD MOSFET's. For single-drain MOSFET's, enhanced ac degradation appears in both threshold voltage and transconductance at stress drain voltages larger than a critical value. On the other hand, for LDD MOSFET's, although the enhanced degradation in threshold voltage and transconductance appears at stress drain voltages larger than a critical value, the enhanced degradation in transconductance appears even under stress drain voltages lower than the critical value. The difference in the ac-enhanced degradation between LDD and single-drain structures can be explained by a hot hole generated neutral-electron-trap model and the change in hot-hole-injected oxide region according to stress bias conditions 相似文献
7.
Y Hasegawa T Hasegawa K Fujii H Konii M Anzo T Aso S Koto M Takada Y Tsuchiya 《Canadian Metallurgical Quarterly》1997,82(1):156-158
A case of huge desmoid tumor successfully treated by hyperthermoradiotherapy is described. A 23-year-old man with familial adenomatous polyposis was operated upon for a desmoid tumor in the mesenterium involving the right kidney and small intestine in 1988. In 1990, the tumor recurred and could not be resected because of the involvement of the vena cava. The tumor grew larger and larger, and occupied two-thirds of the right lower quadrant. Several therapies using sulindac, tamoxifen, prednisolone, indomethacin, luteinizing hormone-releasing hormone analogue, and ascorbate were all ineffective. Finally, the combination of radiation and hyperthermia was used over a 6-month period. At the end of the hyperthermoradiotherapy, the tumor in the abdominal wall was markedly reduced in size, and the protruded abdominal wall became flat. To our best knowledge, this is the first report of the successful treatment of a huge desmoid tumor by hyperthermoradiotherapy. 相似文献
8.
The hot-carrier-injected oxide region in the front and back interfaces is systematically clarified for fully depleted surface-channel nMOSFET's and surface-channel and buried-channel pMOSFET's fabricated on an ultra-thin (50 nm)-film SIMOX wafer. Based on these results, the influence of these injected carriers on front-channel properties is investigated. NMOSFET degradation is shown to be caused by hot-carriers injected into the drain side of the front oxide and pMOSFET degradation by hot-electrons injected into the drain side of both the front oxide and the back oxide. Additionally, it is shown experimentally that these fully depleted devices with effective channel lengths between 0.1-0.2 μm have fairly high hot-carrier immunity, even for single-drain structures 相似文献
9.
Takaaki Wajima Tomoe Shimizu Yasuyuki Ikegami 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2008,83(6):921-927
BACKGROUND: This study aimed to investigate the synthesis of zeolites from paper sludge ash (PSA) with added diatomite to remove both NH4+ and PO43? for water purification. The PSA had low Si and significant Ca contents. Four types of diatomite: white (T‐W) and brown (T‐B) from deposits of marine origin in Takanosu, and white (S‐W) and gray (S‐G) from lacustrine deposits in Shonai, were added to NaOH solution to increase the Si content and thereby synthesize zeolites with high cation exchange capacity (CEC). RESULTS: The order of the amounts of Si extracted from the diatomite to the alkali solution was S‐W > T‐W = T‐B > S‐G, which correlates with the amorphous SiO2 content of diatomite. The original ash without addition of diatomite yielded hydroxysodalite with CEC of about 1.0 mmol g?1. For all samples, the addition of diatomite to the solution yielded zeolite‐P with a higher CEC, but the addition of excess Si inhibited the synthesis of zeolite‐P, and the CEC of the product was low. A product with high CEC including zeolite‐P was obtained in a solution with around 500 mmol L?1 of Si concentration, and had the ability to remove both NH4+ and PO43?. CONCLUSION: Diatomite has the potential for used as an additive for the synthesis of high CEC zeolite from PSA. The product with zeolite‐P exhibited relatively high CEC, capacity for NH4+ uptake, and the ability to remove PO43? by precipitation, which is preferable for water purification applications. Copyright © 2008 Society of Chemical Industry 相似文献
10.
Moritoshi Yasunaga Noriyuki Aibe Yoshiki Yamaguchi Yorihisa Yamamoto Takaaki Awano Ikuo Yoshihara 《Artificial Life and Robotics》2008,12(1-2):219-222
Watching and tracking an object while seeing a much wider view is one of advantages of the eye system. We proposed and developed
a tracking camera system that mimics the eyes by using double-lens modules. In the system, a wide view is captured through
the wide-lens module, while the target in it is tracked and magnified through the telescopic lens module. Electronic circuits
for tracking control are implemented onto the reconfigurable VLSI or FPGA in order to embed the parallelism in the tracking
algorithm into the hardware. A successfully developed FPGA-based prototype performs high-speed tracking at the video-rate.
This work was present in part at the 12th International Symposium on Artificial Life and Robotics, Oita, Japan, January 25–27,
2007 相似文献