全文获取类型
收费全文 | 11724篇 |
免费 | 398篇 |
国内免费 | 41篇 |
专业分类
化学 | 7211篇 |
晶体学 | 128篇 |
力学 | 380篇 |
综合类 | 4篇 |
数学 | 1953篇 |
物理学 | 2487篇 |
出版年
2023年 | 84篇 |
2022年 | 245篇 |
2021年 | 320篇 |
2020年 | 268篇 |
2019年 | 294篇 |
2018年 | 340篇 |
2017年 | 297篇 |
2016年 | 518篇 |
2015年 | 368篇 |
2014年 | 461篇 |
2013年 | 926篇 |
2012年 | 765篇 |
2011年 | 835篇 |
2010年 | 671篇 |
2009年 | 596篇 |
2008年 | 736篇 |
2007年 | 716篇 |
2006年 | 523篇 |
2005年 | 439篇 |
2004年 | 387篇 |
2003年 | 374篇 |
2002年 | 284篇 |
2001年 | 229篇 |
2000年 | 178篇 |
1999年 | 114篇 |
1998年 | 114篇 |
1997年 | 89篇 |
1996年 | 95篇 |
1995年 | 70篇 |
1994年 | 60篇 |
1993年 | 58篇 |
1992年 | 53篇 |
1991年 | 50篇 |
1990年 | 45篇 |
1989年 | 34篇 |
1988年 | 41篇 |
1987年 | 25篇 |
1986年 | 32篇 |
1985年 | 52篇 |
1984年 | 47篇 |
1983年 | 28篇 |
1982年 | 30篇 |
1981年 | 25篇 |
1980年 | 37篇 |
1979年 | 20篇 |
1978年 | 33篇 |
1976年 | 21篇 |
1975年 | 20篇 |
1974年 | 19篇 |
1973年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
251.
The magnetic filtration theory was evaluated to intensify the filtration of industrial fluids by magnetic filters. Effects of filtration velocity and external magnetic field intensity on filter performance were investigated and the dependence of the logarithmic efficiency coefficient on filtration velocity was questioned. It was concluded that change in the magnetic susceptibility of the dispersion particles, caused by external magnetic field, and change in the flow rate properties of the liquid alongside the filter pores are the most essential factors to be considered in the design, development, and modeling of magnetic filtration systems in various industrial areas. 相似文献
252.
253.
254.
Flash DSC crystallization study for blown film grade bimodal HDPE resins. I. Isothermal kinetics and its application of the blown film modeling
下载免费PDF全文
![点击此处可从《Journal of Polymer Science.Polymer Physics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Cecilia D. Treviño‐Quintanilla Ramanan Krishnamoorti Jaime Bonilla‐Ríos 《Journal of Polymer Science.Polymer Physics》2016,54(23):2425-2431
Isothermal ultra‐cooling crystallization tests were conducted on three blown film grade bimodal HDPE resins using an ultrafast scanning calorimeter, the Flash DSC. Isothermal tests were performed to study the regime transition, the thermal nucleation and the spherulitical growth using the Hoffman‐Lauritzen theory in a range between 90 °C and 116 °C. Temperature profile estimations using such data were in good agreement with actual blown film process data. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 2425–2431 相似文献
255.
256.
Benvenuti Jaqueline Capeletti Larissa Brentano Gutterres Mariliz dos Santos João Henrique Zimnoch 《Journal of Sol-Gel Science and Technology》2018,85(2):446-457
Journal of Sol-Gel Science and Technology - This study reports the development of a functional adsorbent synthesized by the molecular imprinting method in a sol–gel matrix. The adsorption... 相似文献
257.
Savas Lemiye Atabek Arslan Cagrialp Hacioglu Fırat Dogan Mehmet 《Journal of Thermal Analysis and Calorimetry》2018,134(3):1657-1666
Journal of Thermal Analysis and Calorimetry - In the current study, huntite and hydromagnesite (HH) was used as flame-retardant additive in linear low-density polyethylene (LLDPE). The effect of HH... 相似文献
258.
259.
The fast transient fluorescence (FTRF) technique was used to study critical exponents at the glass transition in free-radical crosslinking copolymerization (FCC) for two different monomeric systems, methyl methacrylate (MMA) and styrene (S). Pyrene (Py ) was used as a fluorescence probe. The fluorescence lifetimes of Py from its decay traces were measured and used to monitor the gelation process. Changes in the viscosity of the pregel solutions due to glass formation dramatically enhance the fluorescent yield of aromatic molecules. This effect is used to study the glass transition upon gelation of MMA and S monomeric systems as a function of time, at various temperatures and crosslinker concentrations. The results are interpreted in the view of percolation theory. The gel fraction and weight average degree of polymerization exponents β and γ are found to be 0.37 ± 0.02 and 1.66 ± 0.07 in agreement with percolation results. 相似文献
260.
Measurements of the complex permittivity, ε*?=?ε′ – iε″, within the frequency range 200 Hz to 10 MHz for 15 laterally fluoro-substituted terphenyls have been conducted. In most cases the substances exhibited the nematic phase over a broad temperature range. All substances were characterised by negative dielectric anisotropy, and are potentially useful for vertical alignment mode systems. The static permittivity tensor components have been analysed in relation to the dipole structure of the molecules. Dielectric relaxation processes observed in the liquid crystalline (LC) and solid rotator (R) phases (obtained by slow cooling of the samples) are characterised by calculation of the relaxation times and activation barriers. The rotation motions around the short axes are typical for LC phases, whereas rotations about the long axes, accompanied in some cases by internal motions, are present in the R phase. 相似文献