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21.
Recep Ucan Umit Tunca Gurkan Hizal 《Journal of polymer science. Part A, Polymer chemistry》2003,41(13):2019-2025
The controlled polymerization of methyl methacrylate (MMA) in bulk was initiated with p‐chlorobenzenediazonium tetrafluoroborate ( 1 ) and Cu(II) or Cu(I)/Cu(II)/N,N,N′,N″,N″‐pentamethyldietylene triamine (PMDETA) complex system at various temperatures (20, 60, and 90 °C). The proposed polymerization mechanism is based on the Meerwein‐type arylation reaction followed by a reverse atom transfer radical polymerization. In this mechanism, aryl radicals formed by the reaction with 1 and Cu(I) and/or PMDETA initiated the polymerization of MMA. The polymerization is controlled up to a molecular weight of 46,000 at 90 °C. Chain extension was carried out to confirm the controlled manner of the polymerization system. In all polymerization systems, the polydispersity index and initiator efficiency ranged from 1.10–1.57 to 0.10–0.21, respectively. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2019–2025, 2003 相似文献
22.
Zan Ting-quan 《应用数学和力学(英文版)》1988,9(10):985-992
This series of papers is prepared to develop systematically the complicated dynamical behaviors of nonlinear ecosystem and its internal mechanism. In this paper, we state briefly the increasing importance of ecology, describe and comment on the situations and reasons why ecology theory is behind practice. Then, we point out a procedure which modern ecology research should obey, and discuss the four basic characteristics of ecosystem in detail: level, opening, nonlinear and far from equilibrium. At last, we discuss systematically equilibrium and nonequilibrium, stable and unstable, environmental stochasticity and dynamical stochasticity, and conclude that there exists a bridge between deterministic behaviors and stochastic behaviors, which will result in a new model for ecological prediction.Supported by Youth Fund of Chinese Academy of Science and Youth Fund of Lanzhou University. 相似文献
23.
Recep Bekiş İlker Medine Kağan Dağdeviren Türkan Ertay Perihan Ünak 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(2):277-282
Sentinel lymph node detection is widely used to identify lymph nodes that receive lymphatic drainage from a primary tumor.
99mTc labeled iron oxide nanoparticles were prepared to invent a new colorful radioactive agent for sentinel lymph node detection.
Iron oxide nanoparticles were produced by co-precipitation of FeCl3 and FeCl2 in the presence of NaOH. Then iron oxide nanoparticles were labeled with 99mTc. 99mTc labeled nanoparticles (7.4 MBq/0.1 mL) were intradermally injected in the distal hind limb of 16 rabbits. Dynamic and static
lymphoscintigraphic images were taken for 24 h. Labeling efficiencies of 99mTc-iron oxide nanoparticles were over 99%. Their sizes are between 50 and 60 nm. 99mTc-iron oxide nanoparticles were accumulated in the popliteal lymph node in 11 of 16 rabbits (69%). Retention of nanoparticles
in the popliteal lymph node was obvious at from 2nd through 24th hours. The radioactive lymph node was identified easily by
gamma probe. The popliteal lymph node was excised and established for radioactivity and black dye. These black and radioactive
nanoparticles may be potential agent successfully used for sentinel lymph node detection. 相似文献
24.
Yu-Chiang Chao Yi-Sa Huang Hsin-Ping Wang Ssu-Ming Fu Chien-Hao Huang Yen-Chun Liang Wen-Cheng Yang Yu-Sheng Huang Gao-Fong Chang Hsiao-Wen Zan Hsin-Fei Meng Chen-Hsiung Hung Chien-Chung Fu 《Organic Electronics》2011,12(11):1899-1902
A hydrogel sensing film for a real-time and indicator-free detection of Zn2+ is developed by embedding a fluorescent indicator 11,16-bis(phenyl)-6,6,21,21-tetramethyl-m-benzi-6,21-porphodimethene in a hydrogel host poly(2-hydroxyethyl methacrylate). The sensing film shows high stability and selectivity to Zn2+. The sensitivity of the sensing film is increased by fabricating a micron-sized pillar array on the surface of the sensing film to increase the surface area. For Zn2+ concentrations of 10−4 and 10−3 M, the response time is 30 and 3 s, respectively. 相似文献
25.
传统DEA模型在数据两分(偏好与规避)的基础上考察决策单元的有效性,在某些场合不再适用,文章根据决策者的偏好将数据分为三类:规避、偏好、中性类,在此基础上构造评价相对有效性的DEA模型.相较而言,基于数据三分法的DEA模型更具一般性,利用该模型,文章考察了中国近年投入产出绩效问题. 相似文献
26.
Yung Hsu Xiang Fang Lon A. Wang Hsiao-Wen Zan Hsin-Fei Meng Sheng-Hsiung Yang 《Organic Electronics》2014,15(12):3609-3614
We introduced a conformal atomic-layer-deposited aluminum oxide layer to cover the imprint mold to reduce the feature size and to strengthen the mold durability. A nano-hole array pattern with diameter down to 85 nm was successfully transferred to sample substrate to fabricate a vertical organic transistor. The Imprint vertical organic transistor exhibited high output current density as 4.35 cm2/V s and high ON/OFF current ratio as 11,000 at a low operation voltage as 1.5 V. 相似文献
27.
Wide‐Area Strain Sensors based upon Graphene‐Polymer Composite Coatings Probed by Raman Spectroscopy
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Arun Prakash Aranga Raju Amanda Lewis Brian Derby Robert J. Young Ian A. Kinloch Recep Zan Kostya S. Novoselov 《Advanced functional materials》2014,24(19):2865-2874
Functional graphene optical sensors are now viable due to the recent developments in hand‐held Raman spectroscopy and the chemical vapor deposition (CVD) of graphene films. Herein, the strain in graphene/poly (methyl methacrylate) sensor coatings is followed using Raman band shifts. The performance of an “ideal” mechanically‐exfoliated single crystal graphene flake is compared to a scalable CVD graphene film. The dry‐transferred mechanically exfoliated sample has no residual stresses, whereas the CVD sample is in compression following the solvent evaporation during its transfer. The behavior of the sensors under cyclic deformation shows an initial breakdown of the graphene‐polymer interface with the interface then stabilizing after several cycles. The Raman 2D band shift rates per unit strain of the exfoliated graphene are ≈35% higher than CVD graphene making the former more strain sensitive. However, for practical wide‐area applications, CVD graphene coatings are still viable candidates as a Raman system can be used to read the strain in any 5 μm diameter spot in the coating to an absolute accuracy of ≈0.01% strain and resolution of ≈27 microstrains (μs), which compares favorably to commercial photoelastic systems. 相似文献
28.
29.
在多孔γ-Al2O3氧化铝载体上微波合成NaA分子筛膜及气体渗透分离性能 总被引:2,自引:0,他引:2
The paper presented novel synthesis of NaA zeolite membrane with good performance using microwave heating. The method involved two steps, prior seeding 120 nm of LTA crystals on substrate and then employing a secondary hydrothermal synthesis. Effects of seeding times, synthesis time and synthesis times were investigated in this work. The quality evaluation of membranes respectively used single component gases (HE and N2) and H2/N2 (equivalent volume) mixture. The ideal H2,/N2 selectivity increased from 1.90 of the substrate to 6.37 of the three-stage synthesized membrane, which was distinctly higher than the corresponding Knudsen diffusion selectivity of 3.74. However, the real H2/N2 selectivity of the three-stage synthesis was much lower than the corresponding ideal selectivity and close to the corresponding Knudsen diffusion selectivity of 3.74. 相似文献
30.
THERMODYNAMIC ENTROPY MODELS OF THE FROZEN-WALL SYSTEM (Ⅰ) 总被引:2,自引:2,他引:0
Zan Ting-quan 《应用数学和力学(英文版)》1987,8(8):785-792
In this paper, the author describes, and comments on the traditional thermal theory on artificial ground freezing, and points out its important significance and shortcomings. The frozen-wall is analysed by system analysis methods. According to matter levels, the frozen-wall is divided into three sub-systems: frozen colloid system, frozen soil system and frozen-wall system. They correspond to different characteristics. The frozen-wall system is a large open system with multi-levels and multi-aspects. The problems of stability of the system and its control are the key problems in the techniques of artificial ground freezing. Based on non-equilibrium thermodynamics and dissipative structure theory methods, the author discusses and reveals the problems of the formation and stability of the frozen-wall system and its thermodynamic nature, and proposes the thermodynamic entropy models of the system. The result is a great satisfaction. 相似文献