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排序方式: 共有694条查询结果,搜索用时 15 毫秒
131.
Tadashi Toyama Kazunari Sei Ning Yu Hirohide Kumada Daisuke Inoue Hai Hoang Satoshi Soda Young-Cheol Chang Shintaro Kikuchi Masanori Fujita Michihiko Ike 《Water research》2009,43(15):3765-3776
The bacterial community structure in bulk water and in rhizosphere fractions of giant duckweed, Spirodela polyrrhiza, was quantitatively and qualitatively investigated by PCR-based methods using 6 environmental water samples to elucidate the mechanisms underlying selective accumulation of aromatic compound-degrading bacteria in the rhizosphere of S. polyrrhiza. S. polyrrhiza selectively accumulated a diverse range of aromatic compound-degrading bacteria in its rhizosphere, regardless of the origin of water samples, despite no exposure to phenol. The relative abundances of the catechol 1,2-dioxygenase (C12O) gene (C12O DNA) and catechol 2,3-dioxygenase (C23O) gene (C23O DNA) were calculated as the ratios of the copy numbers of these genes to the copy number of 16S rDNA and are referred to as the rhizosphere effect (RE) value. The RE values for C12O DNA and C23O DNA were 1.0 × 101–9.3 × 103 and 1.7 × 102–1.5 × 104 times as high, respectively, in rhizosphere fractions as in bulk water fractions, and these higher values were associated with a notably higher sequence diversity of C12O DNA and C23O DNA. The RE values during phenol degradation were 3.6 × 100–4.3 × 102 and 2.2 × 100–1.7 × 102, respectively, indicating the ability of S. polyrrhiza to selectively accumulate aromatic compound-degrading bacteria in its rhizosphere during phenol degradation. The bacterial communities in the rhizosphere fractions differed from those in the bulk water fractions, and those in the bulk water fractions were notably affected by the rhizosphere bacterial communities. S. polyrrhiza released more than 100 types of phenolic compound into its rhizosphere as root exudates at the considerably high specific release rate of 1520 mg TOC and 214 mg phenolic compounds/d/g root (wet weight). This ability of S. polyrrhiza might result in the selective recruitment and accumulation of a diverse range of bacteria harboring genes encoding C12O and C23O, and the subsequent accelerated degradation of phenol in the rhizosphere. 相似文献
132.
Highly Reproducible and Regulated Conductance Quantization in a Polymer‐Based Atomic Switch 下载免费PDF全文
Karthik Krishnan Manoharan Muruganathan Tohru Tsuruoka Hiroshi Mizuta Masakazu Aono 《Advanced functional materials》2017,27(10)
A detailed understanding of the conductance quantization and resistive switching phenomena in redox‐based memories is crucial for realizing atomic‐scale memory devices and for finding the adequate design principles on which they can be based. Here, the emergence of quantized conductance states and their correlation with resistive switching characteristics in polymer‐based atomic switches are investigated using combinations of current–voltage measurements and first‐principles density functional theory (DFT) simulations. Various conductance states, including integer and half‐integer multiples of a single atomic point contact and fractional conductance variations, are observed in an Ag/polyethylene oxide/Pt device under sweeping of bias voltage. Moreover, highly controllable and reproducible quantized conductance behaviors by tuning the voltage sweep rate and the sweep voltage range, suggesting well‐controlled formation of the atomic point contact, are demonstrated. The device also exhibits longer retention times for higher conductance states. The DFT simulations reveal the transmission eigenstate of geometrically optimized atomic point contact structures and the impact of the atomic configurations and structural stability on the conductance state, which also explains their resistive switching behaviors. The well‐defined, multiple quantized conductance states observed in these polymer‐based atomic switches show promise for the development of new multilevel memory devices. 相似文献
133.
Noriyuki Miyata Hiroyuki IshiiYuji Urabe Taro ItataniTetsuji Yasuda Hisashi YamadaNoboru Fukuhara Masahiko HataMomoko Deura Masakazu SugiyamaMitsuru Takenaka Shinichi Takagi 《Microelectronic Engineering》2011,88(12):3459-3461
Electrical and physical characteristics of the Al2O3/InGaAs interfaces with (1 1 1)A and (1 0 0) orientations were investigated in an attempt to understand the origin of electron mobility enhancement in the (1 1 1)A-channel metal-insulator-semiconductor field-effect-transistor. The (1 1 1)A interface has less As atoms of high oxidation states as probed by X-ray photoelectron spectroscopy. The electrical measurements showed that energy distribution of the interface traps for the (1 1 1)A interface is shifted toward the conduction band as compared to that for the (1 0 0) interface. Laterally-compressed cross-section transmission electron microscopy images showed that the characteristic lengths of the interface roughness are different between the (1 1 1)A and (1 0 0) interfaces. The contributions of the Coulomb and roughness scattering mechanisms are discussed based on the experimental results. 相似文献
134.
Shi-Guang Li Ryosuke Matsubara Toshio Matsusue Masatoshi Sakai Kazuhiro Kudo Masakazu Nakamura 《Organic Electronics》2013,14(4):1157-1162
Innovative sensing systems based on THz electromagnetic waves have been attracting a great deal of attention. Although many THz detectors have been developed over the years, it is currently difficult to manufacture low-cost THz sensing/imaging devices. In the present study, we propose to use organic field-effect transistors (OFETs) and small potential fluctuation against the carriers within them (N. Ohashi, H. Tomii, R. Matsubara, M. Sakai, K. Kudo, M. Nakamura, Appl. Phys. Lett. 91 (2007) 162105). We use THz time-domain spectroscopy for OFETs in which the carrier density in the pentacene active layer is modulated by the gate bias. We found evidence that the accumulated free holes in pentacene films can be excited by THz photons to overcome the surrounding barriers in the fluctuating potential. The Drude–Lorentz model could not account for the shape of the absorption spectra, which suggests that the holes are weakly restricted by the potential fluctuation. The integrated absorption intensity was proportional to the transfer characteristics of the OFETs. The present findings represent an important step toward developing a new class of THz-wave sensors. 相似文献
135.
136.
AgGaTe2 and AgAlTe2 layers were grown on a-plane sapphire substrates by closed-space sublimation. These compounds replace Cd in CdTe with group I and III elements, and are, hence, expected to be ideal novel candidate materials for solar cells. The grown layers were confirmed to be stoichiometric AgGaTe2 and AgAlTe2 by x-ray diffraction (XRD). The AgAlTe2 layers had strong preference for the (112) orientation. The XRD spectrum of the AgGaTe2 layer was different from that of the AgAlTe2 layer, and strong peaks were observed for (103) and (110) diffraction. The variation in orientations of the grown layers was analyzed in detail by use of XRD pole figures, which revealed that the AgGaTe2 layers had an epitaxial relationship with the a-plane sapphire substrates. 相似文献
137.
Masakazu Katsuno Noboru Ohtani Tatsuo Fujimoto Hirokatsu Yashiro 《Journal of Electronic Materials》2005,34(1):91-95
The effect of off-orientation growth has been investigated in terms of stacking fault formation during physical vapor transport
(PVT) growth of silicon carbide (SiC) single crystals on the (11
0) seed crystal surface. Occurrence of stacking fault formation is largely dependent on the direction of off-orientation,
and basal plane stacking fault density is significantly reduced by growing the crystals on a (11
0) seed crystal off-oriented toward 〈0001〉. The density of the basal plane stacking faults rapidly decreases from 100–150
cm−1 to ∼10 cm−1 as the degree of off-orientation is increased from 0 to 10 deg. The results are interpreted in the framework of microscopic
facet formation during PVT growth, and the introduction of off-orientation of seed crystal is assumed to prevent (01
0) and (10
0) microfacet formation on the (11
0) growing surface through modification of the surface growth kinetics and to suppress the stacking fault formation.
An erratum to this article is available at . 相似文献
138.
Masakazu Yamaoka Jens Fortkamp Michael Morr Rolf D. Schmid 《Journal of the American Oil Chemists' Society》1992,69(8):826-828
The effect of an unusual natural fatty acid, 2,4,6,8-tetramethyldecanoic acid (TMDA), on the hydrolysis and acylation of phospholipid
by lipase in isooctane was studied. Lipases examined were fromRhizopus delemar, Candida cylindracea andPseudomonas sp. The lipase was dispersed in isooctane by dioleoylphosphatidylethanolamine (DOPE) with or without the fatty acid and decanoyl-lysophosphatidylcholine
(LPC). The effect of TMDA on both the hydrolysis of DOPE and the acylation of LPC was compared with that of decanoic acid
(DA) by varying the water content. At the higher water content, the hydrolysis of DOPE was enhanced or trace amount of phosphatidylcholine
was produced. Hydrolysis was enhanced more by the addition of TMDA than by DA. The effect of TMDA on the acylation of LPC
was similar to that of DA. 相似文献
139.
The effect of directions of disturbances and modeling errors on the control quality was studied with the aid of singular vectors. It is shown that the material balance type of control structure can handle larger size of set point changes than the conventional type of structure in almost all the directions of set point changes. On the other hand it is shown that the latter can handle larger size of feed disturbances than the former in large portion of the directions
The effect of modeling errors in the relative volatility and the stage efficiency on the robustness was discussed focusing on their directions. It is shown that the column with the high condition number of 57 remains stable even when both parameters were 10° in error
Computer simulations were carried out to ascertain the results obtained. 相似文献
The effect of modeling errors in the relative volatility and the stage efficiency on the robustness was discussed focusing on their directions. It is shown that the column with the high condition number of 57 remains stable even when both parameters were 10° in error
Computer simulations were carried out to ascertain the results obtained. 相似文献
140.
Novel molecular recognition films were prepared from modified polysulfone having perillaldehyde moiety as a side group. The molecular recognition films were obtained from perillaldehyde polysulfone by adopting 9‐ethyladenine as a print molecule. The molecular recognition phenomena were studied by surface plasmon resonance (SPR) spectroscopy. Adsorption of adenosine (As) and guanosine (Gs) in the molecularly imprinted film was studied. Dual adsorption isotherms were observed for As in 9‐EA imprinted films, while nonspecific adsorption isotherms for Gs in those films. This revealed that the molecular recognition sites toward As were constructed in the films thus prepared. The apparent affinity constant toward As determined by using apparent adsorption isotherms ranged from 7.90 × 103 to 3.31 × 104 mol?1 dm3. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献