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51.
Yu Hao Shengbin Wang Junsong Zeng Honglei Li Puheng Yang Baohai Liu Shichao Zhang Yalan Xing 《Ceramics International》2018,44(2):1321-1327
Peapod-like ZnO@C with internal void space has been synthesized by calcination of ZnO/ZnOHF@polydopamine nanorods. By designing both the large void space between particles and external elastic carbon shell, the large volume change of ZnO during charge-discharge process could be effectively relieved. Moreover, the carbon shell functioned as an electronic conductor and elastic barrier, could accelerate the reaction kinetics and confine stable SEI films formation on the outer protective layer to further improve the structural integrity. Benefiting from these structure advantages, the peapod-like ZnO@C presents a prominent electrochemical performance with a retained discharge capacity of 565.1 mA h g?1 at 0.2 A g?1 and high rate capacity of 246.6 mA h g?1 even at 4 A g?1. 相似文献
52.
Feng Li Mingxing Zhou Jiwei Zhai Bo Shen Huarong Zeng 《Journal of the European Ceramic Society》2018,38(14):4646-4652
Lead-free 0.9BaTiO3-0.1(Bi0.9Na0.1)(In0.8Zr0.2)O3 (0.9BT-0.1BNIZ) ferroelectric relaxor ceramic was synthesized by solid-state reaction method. A dense microstructure and fine grain size was obtained with addition of BNIZ content. The dielectric behaviors indicated the dominance of ergodic relaxor phase. The 0.9BT-0.1BNIZ ceramic was found to possess an enhanced recoverable energy density (WR~1.33?J/cm3) and efficiency (η~88%) under 18?kV/mm at room temperature. What’s more, WR is maintained ≥0.53?J/cm3 with η?≥?94% under 10?kV/mm and the variation of WR is less than 15% over 25~140?°C. The high stability of energy storage properties is mainly ascribed to the characteristics of ergodic relaxor phase. The stored energy was released in sub-microseconds (~0.19?μs). The superior current density (CD~796?A/cm2) and the power density (PD~39.8?MW/cm3) were obtained simultaneously. The enhanced WR and the superior charge-discharge performances strongly demonstrate that the BT-based ceramics are promising candidates of high-power pulse capacitor applications. 相似文献
53.
Tao Li Zehui Du Nobumichi Tamura Mao Ye Saikumar Inguva Wei Lu Xierong Zeng Shanming Ke Haitao Huang 《Journal of the European Ceramic Society》2018,38(4):1488-1497
(1-x)Pb(Zn1/3Nb2/3)O3-xPbTiO3 ((1-x)PZN-xPT in short) is one of the most important piezoelectric materials. In this work, we extensively investigated (1-x)PZN-xPT (x = 0.07–0.11) ferroelectric single crystals using in-situ synchrotron μXRD, complemented by TEM and PFM, to correlate microstructures with phase transitions. The results reveal that (i) at 25 °C, the equilibrium state of (1-x)PZN-xPT is a metastable orthorhombic phase for x = 0.07 and 0.08, while it shows coexistence of orthorhombic and tetragonal phases for x = 0.09 and x = 0.11, with all ferroelectric phases accompanied by ferroelastic domains; (ii) upon heating, the phase transformation in x = 0.07 is Orthorhombic → Monoclinic → Tetragonal → Cubic. The coexistence of ferroelectric tetragonal and paraelectric cubic phases was in-situ observed in x = 0.08 above Curie temperature (TC), and (iii) phase transition can be explained by the evolution of the ferroelectric and ferroelastic domains. These results disclose that (1-x)PZN-xPT are in an unstable regime, which is possible factor for its anomalous dielectric response and high piezoelectric coefficient. 相似文献
54.
Isothermal crystallization kinetics and subsequent melting behavior of β‐nucleated isotactic polypropylene/graphene oxide composites with different ordered structure 下载免费PDF全文
Yansong Yu Fangxinyu Zeng Jinyao Chen Jian Kang Feng Yang Ya Cao Ming Xiang 《Polymer International》2018,67(9):1212-1220
The effects of ordered structure on isothermal crystallization kinetics and subsequent melting behavior of β‐nucleated isotactic polypropylene/graphene oxide (iPP/GO) composites were studied using differential scanning calorimetry. The ordered structure status was controlled by tuning the fusion temperature (Tf). The results showed that depending on the variation of crystallization rate, the whole Tf range could be divided into three regions: Region I (Tf > 179 °C), Region II (170 °C ≤ Tf ≤ 179 °C) and Region III (Tf < 170 °C). As Tf decreased from Region I to Region III, the crystallization rate would increase substantially at two transition points, due to the variation of the ordered structure status. Calculation of Avrami exponent n indicated that the ordered structure induced the formation of two‐dimensional growing crystallites rather than three‐dimensional growing crystallites. Moreover, in the case of isothermal crystallization, the ordered structure effect (OSE) can also greatly increase the relative content of β‐phase (βc). In Region II, OSE took place, resulting in evident increase of βc, achieving 92.4% at maximum. The variation of the isothermal crystallization temperature (Tiso) had little influence on the Tf range (Region II) of the OSE. The higher Tf in Region II was more favorable for the formation of higher βc. The ordered structure was favorable for the improvement of the nucleating efficiency of β‐nucleating agent (β‐NE), and was more effective for the improvement of lower β‐NE. © 2018 Society of Chemical Industry 相似文献
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56.
The multi-purpose forensics is an important tool for forge image detection. In
this paper, we propose a universal feature set for the multi-purpose forensics which is
capable of simultaneously identifying several typical image manipulations, including
spatial low-pass Gaussian blurring, median filtering, re-sampling, and JPEG
compression. To eliminate the influences caused by diverse image contents on the
effectiveness and robustness of the feature, a residual group which contains several highpass filtered residuals is introduced. The partial correlation coefficient is exploited from
the residual group to purely measure neighborhood correlations in a linear way. Besides
that, we also combine autoregressive coefficient and transition probability to form the
proposed composite feature which is used to measure how manipulations change the
neighborhood relationships in both linear and non-linear way. After a series of dimension
reductions, the proposed feature set can accelerate the training and testing for the multipurpose forensics. The proposed feature set is then fed into a multi-classifier to train a
multi-purpose detector. Experimental results show that the proposed detector can identify several typical image manipulations, and is superior to the complicated deep CNN-based
methods in terms of detection accuracy and time efficiency for JPEG compressed image
with low resolution. 相似文献
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