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121.
超临界CO2(scCO2)作为一种物理化学性质优良、具有高扩散速率及优良溶解性能的溶剂,在科学研究及工业生产中广受青睐。将scCO2应用于聚合物体系中,CO2 与聚合物间特殊的相互作用有利于CO2分子在聚合物中的吸附与扩散。同时通过CO2的吸附及其对聚合物的溶胀和塑化作用,聚合物所处微观化学环境以及整体结构性质会发生一定的变化。由于傅立叶变换红外光谱(FTIR)技术能够有效地考察化学环境变化对分子结构造成的影响,这一表征技术在超临界CO2作用体系中广为应用。本文主要选取了近年来利用FTIR技术考察scCO2作用于聚合物体系的一些实例,从CO2-聚合物相互作用机理,scCO2对聚合物或生物大分子的加工过程的影响两方面,阐述了利用红外光谱技术在scCO2作用体系中的应用以及前景。 相似文献
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Flix Antonio Corts-Aldana Mnica García-Meln Ignacio Fernndez-de-Lucio Pablo Aragons-Beltrn Rocío Poveda-Bautista 《European Journal of Operational Research》2009,199(3):387
Universities develop technology transfer mechanisms as the tools required to undertake missions committed to the socioeconomic environment. In this work a new proposal to measure the extent to which the goals or strategic objectives of a university are aligned with the results obtained through its technology transfer mechanisms with the local community is presented. This will enable to perform a diagnosis, by comparing the situation sought by the University Management team (expected case) with the actual one that derives from the application of the plans that implement the technology transfer mechanisms (real case). To achieve this, two different Multicriteria Decision Analysis techniques e.g. Analytic Network Process (ANP) and Analytic Hierarchy Process (AHP) will be used. Both the methodology and the MCDA techniques proposed need to be explained and clarified to the different experts who collaborate in the study, hence the facilitating process, key to the whole procedure, will be analysed in detail.The model proposed in this study is applied to analyse the case of the National University of Colombia – Bogotá Campus. Findings show that the following questions can be answered: (i) How much importance is granted by the University Management to the objectives of the University? (ii) To what extent are the objectives of the university fulfilled by the technology transfer mechanisms to the socioeconomic environment? (iii) Are the objectives of the university aligned with the results achieved through the technology transfer mechanisms? 相似文献
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在Jorgenson和Fraumeni的理论框架下提出了一种计算人力资本存量的新方法,并且具体计算了我国2000年人力资本存量以及城乡人力资本存量.分析得出结论:我国人力资本总量巨大,而人均极少;城乡人均人力资本差距很大,且有进一步加大的趋势. 相似文献
125.
Evolution of planetary boundary layer under different weather conditions,and its impact on aerosol concentrations 总被引:6,自引:0,他引:6
Jiannong Quan Yang Gao Qiang Zhang Xuexi Tie Junji Cao Suqin Han Junwang Meng Pengfei Chen Delong Zhao 《中国颗粒学报》2013,11(1):34-40
A field experiment was conducted in Tianjin,China from September 9-30,2010,focused on the evolution of Planetary Boundary Layer(PBL) and its impact on surface air pollutants.The experiment used three remote sensing instruments,wind profile radar(WPR),microwave radiometer(MWR) and micro-pulse lidar(MPL),to detect the vertical profiles of winds,temperature,and aerosol backscattering coefficient and to measure the vertical profiles of surface pollutants(aerosol,CO,SO2,NOx),and also collected sonic anemometers data from a 255-m meteorological tower.Based on these measurements,the evolution of the PBL was estimated.The averaged PBL height was about 1000-1300 m during noon/afternoon-time, and 200-300 m during night-time.The PBL height and the aerosol concentrations were anti-correlated during clear and haze conditions.The averaged maximum PBL heights were 1.08 and 1.70 km while the averaged aerosol concentrations were 52 and 17μg/m3 under haze and clear sky conditions,respectively. The influence of aerosols and clouds on solar radiation was observed based on sonic anemometers data collected from the 255-m meteorological tower.The heat flux was found significantly decreased by haze (heavy pollution) or cloud,which tended to depress the development of PBL,while the repressed structure of PBL further weakened the diffusion of pollutants,leading to heavy pollution.This possible positive feedback cycle(more aerosols→lower PBL height→more aerosols) would induce an acceleration process for heavy ground pollution in megacities. 相似文献
126.
海洋柔性结构涡激振动的流固耦合机理和响应 总被引:1,自引:0,他引:1
对近几十年来国内外在涡激振动的基础研究包括机理认识和动响应分析等方面的进展进行了论述,尤其针对海洋油气平台中的立管、隔水管等细长柔性结构的涡激振动.描述了涡激振动这种典型的非线性流固耦合现象所具有的特征,包括自激、自限制、展向相关、尾迹水动力与结构动力的流固耦合等及其主要影响参数.介绍了目前常用的结构响应预测方法和相关实验.通过讨论当前理论研究和实际工程中的热点问题,诸如多模态宽带振动、浮体运动与水下立管的耦合、响应抑制措施、双向振动、高雷诺数下的大尺度物理实验等,对今后该领域的研究方向进行了力所能及的展望. 相似文献
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For an over-damped linear system subjected to both parametric excitation of colored noise and external excitation of periodically modulated noise, and in the case that the cross-correlation intensity between noises is a time-periodic function,we study the stochastic resonance(SR) in this paper. Using the Shapiro–Loginov formula, we acquire the exact expressions of the first-order and the second-order moments. By the stochastic averaging method, we obtain the analytical expression of the output signal-to-noise ratio(SNR). Meanwhile, we discuss the evolutions of the SNR with the signal frequency, noise intensity, correlation rate of noise, time period, and modulation frequency. We find a new bona fide SR. The evolution of the SNR with the signal frequency presents periodic oscillation, which is not observed in a conventional linear system. We obtain the conventional SR of the SNR with the noise intensity and the correlation rate of noise. We also obtain the SR in a wide sense, in which the evolution of the SNR with time period modulation frequency presents periodic oscillation. We find that the time-periodic modulation of the cross-correlation intensity between noises diversifies the stochastic resonance phenomena and makes this system possess richer dynamic behaviors. 相似文献
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