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141.
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143.
The effects of Cr on the early crystallization stages of Nd4.5Fe77-xCrxB18.5 amorphous ribbons were investigated. Nd4.5Fe77-xCrxB18.5 amorphous ribbons crystallize into (Fe·Cr)3B (Fe3B in Cr-free ribbon) initially and then Nd2Fe23B3 forms. With increasing Cr content, the incubation period for the crystallization of (Fe·Cr)3B and the time interval between (Fe·Cr)3B and Nd2Fe23B3 formation are shortened, and their decomposition is accelerated. (Fe·Cr)2B, Nd2Fe14B and α-Fe form by the decomposition of (Fe·Cr)3B and Nd2Fe23B3. Thus, several reactions occur almost concurrently with the first reaction in the first exothermic peak of the ribbons with
Cr above 3 at.%. Cr has been known to stabilize the (Fe·Cr)3B and suppress the formation of Nd2Fe23B3. However, the present result implies that Cr promotes both the formation and the decomposition of (Fe·Cr)3B and Nd2Fe23B3. Cr has no affect on the crystallization sequence itself but on the kinetics. Therefore, the crystallization sequence of
Nd4.5Fe77-xCrxB18.5 amorphous ribbons is almost the same as those of Cr-free alloys, i.e., amorphous (Am)→Am+(Fe·Cr)3B (Fe3B in Cr-free ribbon)→Am+(Fe·Cr)3B+Nd2Fe23B3→(Fe·Cr)3B+Nd2Fe23B3→Nd2Fe14B+(Fe·Cr)2B+α-Fe→ NdFe4B4+(Fe·Cr)2B+α-Fe. The ambiguities for the early crystallization stages of high Cr ribbons arise from the fact that most of the studies
so far have examined the ribbons annealed above the 60 sec where (Fe·Cr)2B, Nd2Fe14B and α-Fe are detected in the 20 at.% Cr ribbons by the X-ray diffraction pattern. 相似文献
144.
To investigate the biological contaminant levels inside dwellings in Japan, the authors measured fungal indices, airborne mite allergens (Der 1 and Der 2), and suspended particulate matter (SPM). Measurements were continuously conducted at one dwelling located in Yokosuka-city, Kanagawa. The biosensors for fungal index were set at 12 points inside and 2 points outside the dwelling. An SPM sampler was placed in the living room, and samplers for collecting allergens were placed in the living room and in the washroom. The peak level of the fungal index was recorded during July, which is the rainy season in Japan. The highest value in the dwelling was 6.9 in the toilet, and the second highest was 6.6 near a window in the living room that faces southeast, and behind the sofa. The highest monthly SPM level was 21.5 micrograms/m3 during October, and the highest monthly allergen level (Der 1) in the living room was 25.7 pg/m3 during November. A positive relationship between the fungal index and mite allergens was not observed, and the levels of contaminants were not as those found in other studies. However, further study to investigate the distribution of biological contaminants is needed because indoor temperature and relative humidity are comparatively high. 相似文献
145.
Evaluated here are the inhibitory effects on blue-green algae (Microcystis aeruginosa) produced by nine plant-producing phenols (caffeic, p-coumaric, ferulic, protocatechuic, sinapic, syringic, and vanillic acids, catechol, and hydroquinone), two plant-produced acids (quinic and shikimic acid), phenol, resorcinol, hydroxy hydroquinone, and phloroglucinol. Algal assays confirmed growth inhibition of M. aeruginosa by polyphenols, i.e., caffeic/protocatechuic acid, catechol, hydroquinone, hydroxy hydroquinone, and phloroglucinol, and by phenols containing methoxy groups, i.e., vanillic, sinapic, and syringic acids. Accordingly, this indicates good feasibility for controlling growth of M. aeruginosa using such plant-producing polyphenols and/or phenols as additives. A comparison of the inhibitory effects of the polyphenols showed that those induced by polyphenols in which phenolic hydroxy groups bound a benzene ring at ortho- and/or para-positions to another phenolic hydroxy group are stronger than the effects induced by polyphenols in which phenolic hydroxy groups are at only meta-positions. Experiments showed that the only polyphenols demonstrating significant growth inhibition of M. aeruginosa were autoxidized. These results suggest that autoxidation of the polyphenols induces inhibitory effects by producing polyphenol-autoxidized products such as radicals. 相似文献
146.
Teruo Nakai Hossain Md. Shahin Mamoru Kikumoto Hiroyuki Kyokawa Feng Zhang Marcio M. Farias 《Soils and Foundations》2011,51(6):1149-1168
A simple and unified model to describe some features of soil behavior in one dimensional condition is presented in another related paper (Nakai et al., 2011). In the present paper, this one-dimensional model is extended to describe not only the soil features explained in the related paper three-dimensionally (3D), but also to explain other soil features found in multi-dimensional conditions, such as shear behavior considering the influence of intermediate principal stress on the deformation and strength of soils, and the positive and negative soil dilatancy. Firstly, the first step in extending any kind of one-dimensional model to a three-dimensional one is explained in detail: the significance of tij concept and its stress invariants (tN and tS) is explained and compared with the idea of ordinary stress invariants (p and q) used in the Cam clay model. Then, the advanced elastoplastic relations (stages I to III) in the one-dimensional condition presented in the related paper are re-formulated as three-dimensional models—e.g., a model for over consolidated soil, a model for structured soil and a model which considers time-dependent behavior. The three-dimensional models for over consolidated soil (stage I) and structured soil (stage II) are formulated so as to coincide with the subloading tij model developed by Nakai and Hinokio (2004) and by Nakai (2007), respectively. The validity of the models in stage I and stage II is checked by simulations of various shear tests for sands with different void ratios and for over consolidated and natural clays under drained and undrained conditions. The model in stage III is verified by simulations of shear tests with different strain rates, and by simulating creep tests and others, not only for normally consolidated clay but also for non-structured and structured over consolidated clays under drained and undrained conditions. 相似文献
147.
Yoichi Nakai T. Ikeda Y. Kanai T. Kambara N. Fukunishi K. Komaki C. Kondo T. Azuma Y. Yamazaki 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2005,230(1-4):90-95
We observed resonant coherent excitation of the 2s electron to the n = 3 states of 83.5 MeV/u Li-like Fe23+ ions planar-channeling in the plane of a Si crystal. A survival fraction of the Li-like ions was measured as a function of the angle between the incident beam and the [0 0 1] axis. Clear resonance dips corresponding to the transitions of a 2s electron to all the n = 3 states were observed. The transition of each resonance dip was identified by comparing with spectroscopic data. The resonance dips at the transition energies corresponding to the optically forbidden 2s1/2–3s1/2, 2s1/2–3d3/2 and 2s1/2–3d5/2 transitions were observed as well as the resonance dips at transition energies corresponding to the optically allowed 2s1/2–3p1/2 and 2s1/2–3p3/2 transitions. 相似文献
148.
Y Higaki T Kagawa J Fujitani A Kiyonaga M Shindo A Taniguchi Y Nakai K Tokuyama M Suzuki H Tanaka 《Canadian Metallurgical Quarterly》1996,80(3):754-759
The effects of a single bout of exercise on glucose effectiveness (SG) and insulin sensitivity (SI) in 22 sedentary subjects were estimated with a minimal model approach. The intravenous glucose tolerance test (IVGTT) was performed 1) 11 h after an exercise bout on a cycle ergometer at the lactate threshold level (mild exercise) for 60 min, 2) 11 h after an exercise bout at the 4 mM lactate level (hard exercise) for 36 +/- 1 min, 3) 11 h after an exhaustive-exercise bout (exhaustive exercise) for 96 +/- 7 min, or 4) without any prior exercise (control). Only the exhaustive exercise increased the glucose disappearance constant (2.69 +/- 0.28 vs. 2.05 +/- 0.13%/min; P < 0.05) and SI (15.0 +/- 2.0 vs. 10.3 +/- 0.9 x 10(-5) min/pM: P < 0.05) in comparison with the control condition. The SG and SG at zero insulin (GEZI) were not affected by any exercise condition. However, a marked individual difference in GEZI emerged after the exhaustive exercise and could be divided into two subgroups: one decreased in GEZI (0.014 +/- 0.001 vs. 0.007 +/- 0.001 min-1) and the other increased in GEZI (0.014 +/- 0.001 vs. 0.021 +/- 0.003 min-1). The former subgroup was accompanied by elevated levels of plasma creatine kinase (100 +/- 16 vs. 598 +/- 315 IU/l; P < 0.05) and myoglobin (Mb; 46 +/- 4 vs. 126 +/- 47 ng/ml; P < 0.05), whereas the latter subgroup showed no significant change in creatinine kinase (99 +/- 10 vs. 128 +/- 9 IU/l; P > 0.05) and Mb (50 +/- 7 vs. 51 +/- 4 ng/ml; P > 0.05). In both subgroups, SI was similarly increased after the exhaustive exercise. These results thus suggest that a single bout of exercise that results in muscle damage or changes in muscle permeability, as reflected in the increased creatine kinase and Mb levels, decreases GEZI, whereas exhaustive exercise without such alterations increases GEZI. 相似文献
149.
The ultrastructure and morphogenesis of human immunodeficiency virus (HIV) were elucidated by observation with several techniques including immunoelectron microscopy and cryo-microscopy. The virus particle consists of an envelope, a core and matrix. The virus particles were observed extracellularly as having one of three profiles: (1) a centric or an eccentric electron-dense core, (2) rod-shaped electron-dense core, and (3) doughnut-shaped. HIV-1 particles in the hydrated state were observed by high resolution electron cryo-microscopy to be globular, and the lipid membrane was clearly resolved as a bilayer. Many projections around the circumference were seen to be knob-like. The shapes and sizes of the projections, especially head parts, were found to vary in each projection. By isolation with Nonidet P40 and glutaraldehyde, HIV-1 cores were confirmed to consist of p24 protein by immunogold labeling. When the virus enters the cell, two entry modes were found: membrane fusion and endocytosis. No structures resembling virus particles could be seen in the cytoplasm after viral entry. In HIV-1-infected cells, positive reactions by immuno-labeling suggest that HIV-1 Gag may be produced in membrane-bound structures and transported to the cell surface by cytoskeletons. Then a crescent electron-dense layer was first formed underneath the cell membrane. Finally, the virus particle was released from the cell surface. Several cell clones producing defective particles were isolated from MT-4/HIV-1 cells. Among them, doughnut-shaped or teardrop-shaped particles were seen to be produced in the extracellular space. In the doughnut-shaped particles, Gag p17 and p24 proteins faced each other against the inner electron dense ring, suggesting that the inner ring consists of a precursor Gag protein. 相似文献
150.
A preembedding double immunostaining technique was used to study synaptic relations between enkephalin-like immunoreactive and dopamine-beta-hydroxylase-like immunoreactive neurons in the rat area postrema. Enkephalin-like immunoreactive neuronal perikarya and dendrites were found to receive synapses from dopamine-beta-hydroxylase-like immunoreactive axon terminals. Synapses were also found between the same dopamine-beta-hydroxylase-like immunoreactive neurons. Compared with our previous study, the present results provide morphological evidence that dopaminergic and noradrenergic neurons have different synaptic relations with enkephalinergic neurons, suggesting that physiological functions, especially those related to enkephalinergic neurons, may be different from each other in the area postrema. 相似文献