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61.
Xi Wang Weimin Hou Jianjun Zhou Lin Li Yang Li Chi-Ming Chan 《Colloid and polymer science》2007,285(4):449-455
The α- and β-form lamellae of isotactic polypropylene were developed at different temperatures. The melting behaviors of the
lamellae were observed in real time at elevated temperatures using a hot-stage atomic force microscopy. The melting behavior
of the α-form lamellae was determined by the lamellar defects. For the α-form lamellae developed at different undercoolings,
the larger the undercoolings, the relatively higher amount of defect in the lamellae was observed. The lamellae with defects
were melted into lamellar segments, and recrystallization took place during the heating process. The β-form lamellae had lower
thermal stability, and they melted firstly and separately from that of α-form. 相似文献
62.
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64.
Experiments were performed on ultrathin (ca. 35 nm thick) Langmuir-Blodgett films of a double-bond-containing material (vinyl tetracosanoate). The melting/flow point of this deposited material, before and afterin situ polymerization by means of electron beams, was determined by using a Mettler FP5/52 hot stage in conjunction with a polarizing microscope. The melting/flow point observed in the deposited films was found to be higher than the bulk melting point as determined by the capillary method or differential scanning calorimetry. This apparent violation of the principle that a given substance's melting point becomes lower as the sample becomes thinner is explained in terms of the fact that the thin-film process observed is really a combination of two processes, initial melting and subsequent de-wetting, whereas the bulk process involves melting alone. 相似文献
65.
S N Vaidya 《Pramana》1979,12(1):23-32
A theory of melting based on vacancy model is formulated. The polymer solution theory is used for derivation of the melting
equation for a two-species model of melting solid. Under simplifying assumptions the analysis leads to a simple correlation
betweenT
m and 〈v〉, the average energy of interaction between the vibrating atoms. Pseudopotential method is used for calculating 〈v〉 for the alkali metals lithium, sodium, potassium and rubidium at temperatureT
m. The calculated values ofT
m〈v〉 are in accord with those expected from our model. Application to the high pressure melting curves of solids is also discussed. 相似文献
66.
67.
Kohji Kamada Yoshio Katano Yuji Enokido Nariaki Ookubo Isao Yoshizawa 《辐射效应与固体损伤》2013,168(3):275-287
In previous papers, one of the authors (K. K.) has observed the anomalous melting of the surface layer of deuteron implanted Al, containing so-called "tunnel structures", on the electron bombardment in transmission electron microscope. In the present paper, we intended to observe the evidence of the d-d nuclear reaction, expecting neutron emission, associated with the melting phenomenon. However, the result was rather unexpected. The melting phenomenon was certainly observed under the same experimental conditions as before. But, in spite of the melting, neutron emission associated with the nuclear reaction was not observed. And, more unexpectedly, X-ray emission of energy less than roughly 400 v keV was observed when specimens with a bubble structure, which never showed melting, were bombarded with electron beams. Several conceivable mechanisms are discussed which, however, are all not convincing to explain the melting. The melting is attributed to some excess energy generation. The error estimation of the radiation measurements was undertaken. 相似文献
68.
R. Mishra S. P. Tripathy K. K. Dwivedi D. T. Khathing S. Ghosh M. Müller 《辐射效应与固体损伤》2013,168(3):257-269
Abstract The effect of 100 kGy dose of 2 MeV electron irradiation on Poly(ethylene terepthalate) (PET) has been studied by different characterisation techniques such as the Fourier transformed IR spectroscopy, electron spin resonance spectroscopy, thermogravimetric analysis, differential scanning calorimetry and X-ray diffraction analysis. Oxidative degradation leading to amorphisation of the polymer has been observed from spectral analysis. The thermal stability of the polymer was found to decrease due to electron irradiation. The thermal decomposition temperature as well as the melting temperature in case of irradiated PET was found to be decreased due to electron bombardment. A decrease in crystallinity of the polymer has also been observed after irradiation. 相似文献
69.
70.
基于炼焦煤族组成和结构参数的焦炭质量预测模型及其成焦机理 《燃料化学学报》2018,46(12):1409-1422
以五种炼焦煤和44组配合煤为研究对象,在40 kg小焦炉环境下完成煤杯炼焦实验,以煤全组分分离所获得的煤重质组、密中质组和疏中质组收率Y_(HC)、Y_(DMC)、Y_(LMC)及反映煤中氢键缔合情况和脂肪链长短或支链化程度的红外光谱参数I3、I4为主要指标,通过BP神经网络分析方法建立了焦炭质量预测模型,并讨论了模型的特点,分析了新模型下的成焦机理。结果表明,使用新的煤组成结构参数预测焦炭质量具有一定优势,成焦率(CR)、显微强度(MSI)、粒焦反应性(PRI)和反应后强度(PSR)的预测值和实测值有较好一致性,对y=x的拟合相关系数分别达到0.986、0.982、0.956和0.926。模型对CR、MSI和PRI的预测效果较好,九个预测样本的平均偏差分别为0.53%、1.58%和1.28%;但对反应后强度PSR预测效果较差,平均偏差在12.22%。研究结果为建立炼焦配煤新方法提供了良好基础。 相似文献