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991.
Ching-Chang Cho Chieh-Li Chen Rei-Tang Tsai Cha'o-Kuang Chen 《Chemical engineering science》2011,(23):6159
A novel technique is proposed for enhancing the mixing performance of a ‘crisscross’ microfluidic mixer by means of aperiodically-varying perturbation flows. The effects of the perturbation and geometry parameters on the fluid flow characteristics and mixing performance are analyzed numerically. In performing the simulations, the flow field and species concentration field are obtained by solving the two-dimensional time-dependent Navier–Stokes equations and the convection–diffusion equation, respectively. In addition, the oscillating source used to modulate the perturbation flows is modeled using the Sprott system. The results show that the irregularly-alternating flow perturbations cause a repeated stretching and folding of the species streams and enhance the mixing performance as a result. It is shown that an effective improvement in the mixing performance can be obtained through a suitable choice of the Sprott system scaling factor. Moreover, it is shown that having assigned an appropriate scaling factor, the mixing performance can be further improved by specifying suitable values of the geometry and perturbation parameters. 相似文献
992.
Mu-Yi Hua Yu-Chen Lin Rung-Ywan Tsai Hsiao-Chien Chen Yin-Chih Liu 《Electrochimica acta》2011,(25):49
We have developed a polyaniline/carboxy-functionalized multiwalled carbon nanotube (PAn/MWCNTCOOH) nanocomposite by blending the emeraldine base form of polyaniline (PAn) and carboxy-functionalized multiwalled carbon nanotubes (MWCNT) in dried dimethyl sulfoxide (DMSO) at room temperature. The conductivity of the resulting PAn/MWCNTCOOH was 3.6 × 10−3 S cm−1, mainly as a result of the protonation of the PAn with the carboxyl group and the radical cations of the MWCNT fragments. Horseradish peroxidase (HRP) was immobilized within the PAn/MWCNTCOOH nanocomposite modified Au (PAn/MWCNTCOOH/Au) electrode to form HRP/PAn/MWCNTCOOH/Au for use as a hydrogen peroxide (H2O2) sensor. The adsorption between the negatively charged PAn/MWCNTCOOH nanocomposite and the positively charged HRP resulted in a very good sensitivity to H2O2 and an increased electrochemically catalytical current during cyclic voltammetry. The HRP/PAn/MWCNTCOOH/Au electrode exhibited a broad linear response range for H2O2 concentrations (86 μM–10 mM). This sensor exhibited good sensitivity (194.9 μA mM−1 cm−2), a fast response time (2.9 s), and good reproducibility and stability at an applied potential of −0.35 V. The construction of the enzymatic sensor demonstrated the potential application of PAn/MWCNTCOOH nanocomposites for the detection of H2O2 with high performance and excellent stability. 相似文献
993.
Rong‐Jer Lee Wei‐Cheng Tsai Wen‐Tung Cheng Bin‐Chen Shiue Jiang‐Jen Lin 《应用聚合物科学杂志》2011,119(6):3437-3445
Self‐assembled and crystallized composites made from montmorillonite (MMT) by intercalation with poly(ether amine) salts and copper(II) [Cu(II)] ions simultaneously were studied. The manipulation of the silicate unit structure of the secondary (001) lattice by physically imposed osmotic pressure on the platelet interlayer was used. Divalent copper salt assisted a strong depletion effect with balancing the counterions in the clay interlayer and resulted in the extension of the dimensions of the (001) plane by increasing the spacing expansion by more than two orders of magnitude. The simultaneous adsorption of Cu(II) and intercalation of poly(oxypropylene)amine (POP) salts onto the MMT units ultimately minimized their amorphous aggregation through electrostatic attraction between the negative surface and positive edge among the silicate units. Alternatively, the attraction force through face‐to‐face stacking on the silicate surface is proposed, and the conformation of the POP/Cu(II) complex aligned with the approaching platelets to form orderly structures. X‐ray diffraction of the MMT units exhibited a high order of reflection (i.e., (006)) in Bragg's pattern; this implied a repetitive regularity between the plate–plate distances. The high regularity disappeared when the Cu(II) adsorption exceeded the critical clay cation‐exchange capacity of 1.4. The conformation of the flexible polyether backbone was altered and could no longer sustain the plate distance and the symmetric packing was destroyed when the basal spacing was decreased from 82.6 to 18.0 Å. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
994.
Chiou‐Juy Chen Hsu‐Tung Lu Wen‐Yen Tseng I‐Hsiang Tseng Shih‐Liang Huang Mei‐Hui Tsai 《应用聚合物科学杂志》2011,122(1):648-656
Polyimide (PI)/silica hybrid membranes with high contact angles were prepared through the in situ sol–gel process. The precursor, poly(amic acid) with controlled block chain length, was synthesized using 4,4′‐diaminodiphenyl ether (ODA), 3,3′,4,4′‐benzophenone‐tetracarboxylic dianhydride (BTDA) and 3‐aminopropyl‐trimethoxysilane (APrTMOS) or 3‐aminopropyldimethylethoxysilane (APDiMOS). And then, phenyltrimethoxysilane (PTS) or tetramethoxysilane (TMOS) or methyltrimethoxysilane (MTrMOS) was respectively, added to the above polyamic acid and mixed thoroughly. Following curing reaction, the PI/silica hybrid membranes with different cross‐linkages, silica content, and hydrophobic properties were prepared. The effect on the formation of PI imide ring during imidization reaction is increased as the increase of silanes content and characterized by frequency shiftment and absorbance ratio of Fourier transform infrared (FTIR) measurements. All the hybrid membranes show high transparency though with high silica contents. The storage modulus, tan δ, and damping intensity by DMA measurements are all correlated with silane content or block chain length. And all these membranes with silane content possess high contact angle as compared to pure PI without any silanes added and the contact angles increase with increasing the silane content. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
995.
Ying‐Gev Hsu Xing‐Wei Su Kuan‐Hung Lin Yen‐Shen Wan Jhih‐Cheng Chen Jan‐An Guu Pi‐Chen Tsai 《应用聚合物科学杂志》2011,119(2):693-701
The surface‐modified diamond and PET film underwent photopolymerization rapidly with a binder agent to afford coating films of interpenetrating network (IPN) structure. The coating films thus formed exhibit higher tensile strength, thermal stability, and adhesion strength to the PET film. The inert surfaces of pristine diamond (PD) and PET film were modified by different chemicals and procedures to introduce epoxide and methacryloyl groups, respectively, on their surfaces. A coating agent consisting of an epoxide group containing modified diamond (called ED), a binder agent, and photoinitiators was prepared. After applying the coating agent to the substrate (a glass plate or a methacryloyl group containing PET film, MMA‐PET) and degassing under reduced pressure, the thin film of the coating agent was exposed to UV light (λmax; 365 nm) at room temperature to yield a coating film of IPN‐structure. The tensile strength and thermal properties of the ED‐containing free coating film (called free film) increased with the amount of ED embedded, whereas the strength of the PD‐containing free film decreased with the amount of PD embedded. The adhesion strength of the coating film on the MMA‐PET improved significantly by the free radical polymerization of the methacryloyl groups on the MMA‐PET and the acrylate resin in the binder agent. The surface photoreactions of ED and MMA‐PET with the binder agent were confirmed by modeling. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
996.
Tsai CC Mikes P Andrukh T White E Monaenkova D Burtovyy O Burtovyy R Rubin B Lukas D Luzinov I Owens JR Kornev KG 《Nanoscale》2011,3(11):4685-4695
We describe a method of fabrication of nanoporous flexible probes which work as artificial proboscises. The challenge of making probes with fast absorption rates and good retention capacity was addressed theoretically and experimentally. This work shows that the probe should possess two levels of pore hierarchy: nanopores are needed to enhance the capillary action and micrometer pores are required to speed up fluid transport. The model of controlled fluid absorption was verified in experiments. We also demonstrated that the artificial proboscises can be remotely controlled by electric or magnetic fields. Using an artificial proboscis, one can approach a drop of hazardous liquid, absorb it and safely deliver it to an analytical device. With these materials, the paradigm of a stationary microfluidic platform can be shifted to the flexible structures that would allow one to pack multiple microfluidic sensors into a single fiber. 相似文献
997.
The present study aims to investigate the effect of suspended nanoparticles in base fluids, namely nanofluids, on the thermal resistance of a disk-shaped miniature heat pipe [DMHP]. In this study, two types of nanoparticles, gold and carbon, in aqueous solution are used respectively. An experimental system was set up to measure the thermal resistance of the DMHP with both nanofluids and deionized [DI] water as the working medium. The measured results show that the thermal resistance of DMHP varies with the charge volume and the type of working medium. At the same charge volume, a significant reduction in thermal resistance of DMHP can be found if nanofluid is used instead of DI water. 相似文献
998.
999.
Cheng-Shong Hong Sheng-Yuan Chu Cheng-Che Tsai Wen-Chang Su Hsiu-Hsien Su 《Ceramics International》2013
This study fabricates capacitors with two-layer structure and different compositions, 0.8Pb(Fe2/3W1/3)O3–0.2PbTiO3–MnO and 0.7Pb(Fe2/3W1/3)O3–0.3PbTiO3–MnO, by using the conventional solid state oxide reaction method. By using the temperature compensation effect and adjusting the thickness ratio of the two layers with different compositions, the temperature–dielectric peak is enhanced and smoothed. The dielectric loss, space charge polarization and dc conduction are suppressed at the highest temperature region. Furthermore, the Maxwell–Wagner model is used to fit and explain the dielectric behaviors. This study also provides suggestions and discussion related to the effect of the interfacial region based on the experimental data and fitting results. 相似文献
1000.