全文获取类型
收费全文 | 1559篇 |
免费 | 27篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 86篇 |
综合类 | 1篇 |
化学工业 | 398篇 |
金属工艺 | 47篇 |
机械仪表 | 35篇 |
建筑科学 | 26篇 |
能源动力 | 57篇 |
轻工业 | 104篇 |
水利工程 | 4篇 |
石油天然气 | 2篇 |
无线电 | 163篇 |
一般工业技术 | 231篇 |
冶金工业 | 220篇 |
原子能技术 | 46篇 |
自动化技术 | 171篇 |
出版年
2022年 | 18篇 |
2021年 | 34篇 |
2020年 | 10篇 |
2019年 | 13篇 |
2018年 | 27篇 |
2017年 | 21篇 |
2016年 | 26篇 |
2015年 | 23篇 |
2014年 | 26篇 |
2013年 | 86篇 |
2012年 | 66篇 |
2011年 | 84篇 |
2010年 | 62篇 |
2009年 | 67篇 |
2008年 | 58篇 |
2007年 | 64篇 |
2006年 | 56篇 |
2005年 | 52篇 |
2004年 | 42篇 |
2003年 | 52篇 |
2002年 | 33篇 |
2001年 | 27篇 |
2000年 | 24篇 |
1999年 | 33篇 |
1998年 | 95篇 |
1997年 | 79篇 |
1996年 | 47篇 |
1995年 | 39篇 |
1994年 | 31篇 |
1993年 | 40篇 |
1992年 | 18篇 |
1991年 | 22篇 |
1990年 | 17篇 |
1989年 | 23篇 |
1988年 | 11篇 |
1987年 | 12篇 |
1986年 | 10篇 |
1985年 | 14篇 |
1984年 | 15篇 |
1983年 | 14篇 |
1982年 | 10篇 |
1981年 | 10篇 |
1980年 | 6篇 |
1979年 | 6篇 |
1978年 | 6篇 |
1977年 | 14篇 |
1976年 | 13篇 |
1975年 | 5篇 |
1974年 | 6篇 |
1973年 | 9篇 |
排序方式: 共有1591条查询结果,搜索用时 343 毫秒
1.
Shouko Nishida Masaya Shibano Hiroshi Kamitakahara Toshiyuki Takano 《International journal of molecular sciences》2015,16(12):29093-29102
We recently observed that the decanoylation of N-phenylthiocarbamoyl chitosan (2) with a mixture of decanoic anhydride and pyridine at 60 °C for 24 h afforded N,N-(decanoyl)phenythiocarbamoyl-/2-isothiocynato chitosan decanoate (3b) rather than the expected product N,N-(decanoyl)phenylthiocarbamoyl chitosan decanoate (3a). This result suggested that some of the N,N-(decanoyl)phenylthiocarmbamoyl groups had been converted to isothiocyanate groups during the decanoylation process. The subsequent reaction of compound 3b with aniline gave N,N-(decanoyl)phenylthiocarbamoyl/N-phenylthiocarbamoyl chitosan decanoate (4) in high yield. A solution of compound 4 in CHCl3 was then added to a solution of copper decanoate (5) in the same solvent, and the resulting mixture was cast onto a glass plate to give a cast film. The film was annealed at 200 °C in an oven to give a greenish film, which showed good near-infrared absorption characteristic in the range of 800–2200 nm. 相似文献
2.
N Okada S Sato T Sasou M Aoyama K Nishida K Yoshikawa 《Canadian Metallurgical Quarterly》1993,129(4):403-407
Ambiguous abdominal situs, asplenia/polysplenia and severe cardiac malformations characterize heterotaxy in humans. These anomalies result from the inability of the developing embryo to establish normal left-right asymmetry. We have studied an interesting family in which the heterotaxy phenotype segregates as an X-linked recessive trait. In order to map the heterotaxy locus (HTX), we have analysed 39 family members using highly-polymorphic microsatellite markers from the X chromosome. One of these markers, DXS994, shows no recombination with the disease locus in 20 informative meioses. Linkage analysis results in a maximum lod score of 6.37. Current genetic and physical mapping data assign the order of loci in Xq24-q27.1 as cen-DXS1001-(DXS994, HTX)-DXS984-tel. These results establish the first mapping assignment of situs abnormalities in humans. 相似文献
3.
Y Nishida T Fujimoto A Takagi I Honjo K Ogawa 《Canadian Metallurgical Quarterly》1993,65(1-2):274-280
Localization of fodrin, a membrane skeletal protein, in the outer hair cell of the guinea pig cochlea was examined by immunocytochemical techniques. By immunofluorescence microscopy, fodrin was observed in the cuticular plate, in the infracuticular network and along the lateral wall. By immunoelectron microscopy of ultrathin cryosections, labeling for fodrin along the lateral wall was localized between the cell membrane and the outermost layer of the subsurface cisternae. Furthermore, pre-embedding immunoelectron microscopy of permeabilized specimens showed that most immunogolds for fodrin were on the thin cross-linking component of the cortical lattice. The results indicate that fodrin is a constituent of the cortical lattice which is thought to play an important role in outer hair cell motility. 相似文献
4.
5.
Asobe M. Tadanaga O. Miyazawa H. Nishida Y. Suzuki H. 《Quantum Electronics, IEEE Journal of》2005,41(12):1540-1547
We propose a new multiple quasi-phase-matched wavelength converter based on the continuous phase modulation of a /spl chi//sup (2)/ grating for use in variable wavelength conversion. A numerical study shows that the proposed device exhibits a high conversion efficiency, flexible design, and robust fabrication tolerance. A waveguide device fabricated by annealed proton exchange agrees well with the numerical design. Fine-tuning the device enabled us to demonstrate variable wavelength conversion between signals on the standard optical frequency grid. Using the device, we also demonstrated fast (<100 ps) wavelength switching of 4-channel 40-Gb/s signals. The obtained results clearly show that the proposed multiple quasi-phase-matched devices will be useful when constructing future flexible photonic networks. 相似文献
6.
Toru Ikegami Hideyuki Negishi Dai Kitamoto Keiji Sakaki Tomohiro Imura Masayoshi Okamoto Yasushi Idemoto Nobuyuki Koura Tsuneji Sano Kenji Haraya Hiroshi Yanagishita 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2005,80(4):381-387
In order to produce highly concentrated bioethanol by pervaporation using an ethanol‐permselective silicalite membrane, techniques to suppress adsorption of succinic acid, which is a chief by‐product of ethanol fermentation and causes the deterioration in pervaporation performance, onto the silicalite crystals was investigated. The amount adsorbed increased as the pH of the aqueous succinic acid solution decreased. The pervaporation performance also decreased with decreasing pH when the ternary mixtures of ethanol/water/succinic acid were separated. Using silicalite membranes individually coated with two types of silicone rubber, pervaporation performance was significantly improved in the pH range of 5 to 7, when compared with that of non‐coated silicalite membranes in ternary mixtures of ethanol/water/succinic acid. Moreover, when using a silicalite membrane double‐coated with the two types of silicone rubber, pervaporation performance was stabilized at lower pH values. In the separation of bioethanol by pervaporation using the double‐coated silicalite membrane, removal of accumulated substances having an ultraviolet absorption maximum at approximately 260 nm from the fermentation broth proved to be vital for efficient pervaporation. Copyright © 2005 Society of Chemical Industry 相似文献
7.
A novel dynamic survivable routing in WDM optical networks with/without sparse wavelength conversion
Vinh Trong Le Xiaohong Jiang Son Hong Ngo Susumu Horiguchi Yasushi Inoguchi 《Optical Switching and Networking》2006,3(3-4):173-190
In this paper, we study the dynamic survivable routing problem, both in optical networks without wavelength conversion and in optical networks with sparse wavelength conversion, and propose a novel hybrid algorithm for it based on the combination of mobile agents technique and genetic algorithms (GA). By keeping a suitable number of mobile agents in the network to cooperatively explore the network states and continuously report cycles (that are formed by two disjoint-link routes) into the routing tables, our new hybrid algorithm can promptly determine the first population of cycles for a new request based on the routing table of its source node, without the time consuming process associated with current GA-based lightpath protection schemes. We further improve the performance of our algorithm by introducing a more advanced fitness function that is suitable for both the above networks. Extensive simulation studies on the ns-2 network simulator show that our hybrid algorithm achieves a significantly lower blocking probability than the conventional survivable routing algorithms for all the cases we studied. 相似文献
8.
An applicability of quinone biomarker to the analysis of hillslope runoff was investigated. At first, quinone profiles of three streams as well as a hillslope runoff in a forested headwater catchment were compared. The quinone composition of hillslope runoff differed from others. Moreover, there were remarkable differences in quinone profile of hillslope runoff under different rainfall conditions. Then, the behavior of quinone biomarker during the increase and decrease of hillslope runoff after a rainfall event was examined. The fractional changes in Q-9 (H2), Q-10 (H2), Q-11, MK-6 and MK-10 suggested the effect of interflow. 相似文献
9.
10.
Hiraki M. Uano K. Minami M. Sato K. Matsuzaki N. Watanabe A. Nishida T. Sasaki K. Seki K. 《Solid-State Circuits, IEEE Journal of》1992,27(11):1568-1574
A BiCMOS logic circuit applicable to sub-2-V digital circuits has been developed. A transiently saturated full-swing BiCMOS (TS-FS-BiCMOS) logic circuit operates twice as fast as CMOS at 1.5-V supply. A newly developed transient-saturation technique, with which bipolar transistors saturate only during switching periods, is the key to sub-2-V operation because a high-speed full-swing operation is achieved to remove the voltage loss due to the base-emitter turn-on voltage. Both small load dependence and small fan-in dependence of gate delay time are attained with this technique. A two-input gate fabricated with 0.3-μm BiCMOS technology verifies the performance advantage of TS-FS-BiCMOS over other BiCMOS circuits and CMOS at sub 2-V supply 相似文献