全文获取类型
收费全文 | 7989篇 |
免费 | 346篇 |
国内免费 | 117篇 |
专业分类
化学 | 6054篇 |
晶体学 | 48篇 |
力学 | 409篇 |
数学 | 794篇 |
物理学 | 1147篇 |
出版年
2024年 | 19篇 |
2023年 | 65篇 |
2022年 | 314篇 |
2021年 | 396篇 |
2020年 | 397篇 |
2019年 | 391篇 |
2018年 | 400篇 |
2017年 | 375篇 |
2016年 | 516篇 |
2015年 | 363篇 |
2014年 | 479篇 |
2013年 | 882篇 |
2012年 | 671篇 |
2011年 | 595篇 |
2010年 | 397篇 |
2009年 | 370篇 |
2008年 | 361篇 |
2007年 | 317篇 |
2006年 | 212篇 |
2005年 | 188篇 |
2004年 | 125篇 |
2003年 | 127篇 |
2002年 | 96篇 |
2001年 | 34篇 |
2000年 | 18篇 |
1999年 | 27篇 |
1998年 | 18篇 |
1997年 | 21篇 |
1996年 | 23篇 |
1995年 | 15篇 |
1994年 | 17篇 |
1993年 | 13篇 |
1992年 | 14篇 |
1991年 | 13篇 |
1990年 | 13篇 |
1989年 | 9篇 |
1988年 | 9篇 |
1987年 | 15篇 |
1986年 | 5篇 |
1985年 | 13篇 |
1984年 | 14篇 |
1982年 | 14篇 |
1981年 | 10篇 |
1980年 | 15篇 |
1979年 | 8篇 |
1978年 | 9篇 |
1977年 | 7篇 |
1976年 | 6篇 |
1971年 | 5篇 |
1969年 | 5篇 |
排序方式: 共有8452条查询结果,搜索用时 0 毫秒
91.
Monajati Saharkhiz Mohammad Hossein Ghorbani Bahram 《Journal of Thermal Analysis and Calorimetry》2021,145(3):1385-1411
Journal of Thermal Analysis and Calorimetry - Due to limited energy supply sources and environmental issues, the use of renewable energy to replace fossil fuels and reduce pollution has increased.... 相似文献
92.
Zheng Yuanzhou Zhang Xinzhu Soleimani Mobareke Mohammad Taghi Hekmatifar Maboud Karimipour Arash Sabetvand Roozbeh 《Journal of Thermal Analysis and Calorimetry》2021,144(6):2515-2523
Journal of Thermal Analysis and Calorimetry - It is interesting to investigate the number of nanoparticle (NP) and temperature effects on H2O/CuO nanofluid thermal conductivity and the atomic... 相似文献
93.
Vahedi Mohammad Mollaei Barzi Yaser Firouzi Masoumeh 《Journal of Thermal Analysis and Calorimetry》2021,146(3):1297-1321
Journal of Thermal Analysis and Calorimetry - The aim of this paper is to achieve a smaller and cheaper heat exchanger with similar performance. To fulfill this demand, ANSYS-Fluent software and... 相似文献
94.
Mohammad Baghery Mahmoudian Ali Reza Nejad Ahmad Iran 《Russian Journal of Electrochemistry》2021,57(6):567-579
Russian Journal of Electrochemistry - Zinc selenide has applications in the fabrication of low-cost solar cells and optoelectronic devices. Due to its optical properties and large direct bandgap,... 相似文献
95.
Dinesh R. Hussain S. Imran Roseline A. Ameelia Kalaiselvam S. 《Journal of Thermal Analysis and Calorimetry》2021,145(6):2935-2949
Journal of Thermal Analysis and Calorimetry - In this paper, the variation of thermophysical properties such as the thermal conductivity, thermal energy storage capacity, viscosity, and phase... 相似文献
96.
Edalatifar Mohammad Tavakoli Mohammad Bagher Ghalambaz Mohammad Setoudeh Farbod 《Journal of Thermal Analysis and Calorimetry》2021,146(3):1435-1452
Journal of Thermal Analysis and Calorimetry - In the present study, an advanced type of artificial intelligence, a deep neural network, is employed to learn the physic of conduction heat transfer... 相似文献
97.
Efficacy of incorporating PCMs into the commercial wall on the energy-saving annual thermal analysis
Nguyen Quyen Naghieh Alireza Kalbasi Rasool Akbari Mohammad Karimipour Arash Tlili Iskander 《Journal of Thermal Analysis and Calorimetry》2021,143(3):2179-2187
Journal of Thermal Analysis and Calorimetry - In this study, the efficacy of incorporating phase change material (PCM) into the building walls on the annual heat transfer reduction is examined.... 相似文献
98.
Optical Review - Both Fabry–Pérot interferometry and the DC electrochemical method have been simultaneously used for the first time to measure in situ the anodic current density (J) of... 相似文献
99.
Nowadays, pharmaceutical antibiotics are known as a serious class of pollutants. Therefore, it is important to develop effective methods for removing these pollutants from aqueous media. Different methods were applied for this purpose, and among these methods, chemical reduction by a cheap and eco‐friendly nanocatalyst is the most efficient and simplest method. In this research, based on graphene oxide supported by zero‐valent iron in mono‐, bi‐, and tri‐metallic systems, various nanocomposites were synthesized and used to degrade tetracycline as a model antibiotic from aqueous media. An investigation was carried out on the synergic effect among graphene oxide and the nano zero‐valent iron‐based tri‐metallic system as well as removal efficiencies. It was found that higher degradation efficiency is yielded by graphene oxide supported by Fe/Cu/Ag tri‐metallic system. The maximum synergic effect occurs at an acidic medium. The Brunauer–Emmett–Teller, Fourier transform spectroscopy, scanning electron microscopy‐energy dispersive X‐ray analysis, transmission electron microscopy, and X‐ray diffraction analysis were used to characterize the synthesized nanocomposites, which has successfully proved the loading of nanoscale Fe/Cu/Ag tri‐metallic on a graphene oxide support. The central composite design was used to model and optimize all involved variables affecting antibiotic removal efficiency. The consequences illustrated the optimum condition regarding the removal of 50 ppm of tetracycline, for the nanocomposites dose of 3.0 mg ml?1, the contact time of 30 min, and pH of 2, was achieved using the simplex non‐linear optimization method. Moreover, antibiotic adsorption kinetic models were also investigated. Finally, the tetracycline removal from aqueous media at different concentrations, 25, 50, and 75 ppm, was successful by applying the proposed nanocomposite, and the results showed tetracycline removal efficiencies of above 70%. 相似文献
100.
Maryam S. Sadeghi Mohammad Reza Moghbeli William A. Goddard III 《Journal of polymer science. Part A, Polymer chemistry》2021,59(7):614-626
We followed the self-assembly of high-molecular weight MePEG- b -PCL (poly(methyl ethylene glycol)-block-poly(ε-caprolactone)) diblock and MePEG- b -PBO- b -PCL (poly(methyl ethylene glycol)-block-poly(1,2-butylene oxide)-block-poly(ε-caprolactone)) into micelles using molecular dynamics simulation with a coarse grain (CG) force field based on quantum mechanics (CGq FF). The triblock polymer included a short poly(1,2-butylene oxide) (PBO) at the hydrophilic-hydrophobic interface of these systems. Keeping the hydrophilic length fixed (MePEG45), we considered 250 chains in which the hydrophobic length changed from PCL44 or PBO6- b -PCL43 to PCL62 or PBO9- b -PCL61. The polymers were solvated in explicit water for 2 μs of simulations at 310.15 K. We found that the longer diblock system undergoes a morphological transition from an intermediate rod-like micelle to a prolate-sphere, while the micelle formed from the longer triblock system is a stable rod-like micelle. The two shorter diblock and triblock systems show similar self-assembly processes, both resulting in slightly prolate-spheres. The dynamics of the self-assembly is quantified in terms of chain radius of gyration, shape anisotropy, and hydration of the micelle cores. The final micelle structures are analyzed in terms of the local density components. We conclude that the CG model accurately describes the molecular mechanisms of self-assembly and the equilibrium micellar structures of hydrophilic and hydrophobic chains, including the quantity of solvent trapped inside the micellar core. 相似文献