全文获取类型
收费全文 | 464993篇 |
免费 | 6843篇 |
国内免费 | 1225篇 |
专业分类
化学 | 248834篇 |
晶体学 | 5349篇 |
力学 | 19475篇 |
综合类 | 13篇 |
数学 | 56764篇 |
物理学 | 142626篇 |
出版年
2021年 | 3838篇 |
2020年 | 4655篇 |
2019年 | 4857篇 |
2018年 | 6293篇 |
2017年 | 6178篇 |
2016年 | 9835篇 |
2015年 | 6423篇 |
2014年 | 9486篇 |
2013年 | 22247篇 |
2012年 | 17239篇 |
2011年 | 21150篇 |
2010年 | 14489篇 |
2009年 | 14168篇 |
2008年 | 19404篇 |
2007年 | 19274篇 |
2006年 | 17834篇 |
2005年 | 15899篇 |
2004年 | 14521篇 |
2003年 | 12551篇 |
2002年 | 11566篇 |
2001年 | 13604篇 |
2000年 | 10022篇 |
1999年 | 7712篇 |
1998年 | 6355篇 |
1997年 | 6223篇 |
1996年 | 6100篇 |
1995年 | 5766篇 |
1994年 | 5743篇 |
1993年 | 5621篇 |
1992年 | 6174篇 |
1991年 | 6124篇 |
1990年 | 5907篇 |
1989年 | 5663篇 |
1988年 | 5704篇 |
1987年 | 5599篇 |
1986年 | 5270篇 |
1985年 | 6944篇 |
1984年 | 7092篇 |
1983年 | 5681篇 |
1982年 | 5768篇 |
1981年 | 5763篇 |
1980年 | 5291篇 |
1979年 | 5706篇 |
1978年 | 5877篇 |
1977年 | 5761篇 |
1976年 | 5650篇 |
1975年 | 5232篇 |
1974年 | 5168篇 |
1973年 | 5178篇 |
1972年 | 3587篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Butenko A. V. Galimov A. R. Meshkov I. N. Syresin E. M. Tolstikhina I. Yu. Tuzikov A. V. Philippov A. V. Khodzhibagiyan H. G. Shevel’ko V. P. 《JETP Letters》2021,113(12):752-756
JETP Letters - The results of the first run (December 2020) for the commissioning of the new superconducting synchrotron Booster at the Joint Institute for Nuclear Research are presented. Vacuum... 相似文献
42.
Zuev L. B. Barannikova S. A. Kolosov S. V. Nikonova A. M. 《Physics of the Solid State》2021,63(1):47-53
Physics of the Solid State - The behavior of localized plastic flow autowaves in a Fe–Ni–Cr alloy at temperatures 143 K ≤ T ≤ 420 K is considered. The temperature variation... 相似文献
43.
Crystallography Reports - Electron backscattered diffraction (EBSD) has been used to analyze structures of natural minerals and artificial compounds for almost three decades. In recent years, it is... 相似文献
44.
International Applied Mechanics - The method for determination of the longitude and latitude of a moving object is presented. This method is based on measuring the vehicle’s angular rate... 相似文献
45.
Kuz’mina L. G. Navasardyan M. A. Kalle P. Bezzubov S. I. 《Crystallography Reports》2021,66(3):420-423
Crystallography Reports - The crystal and molecular structures of Cl–C6H4–O–C16H33 (I) have been studied, and its differential scanning calorimetry (DSC) study is performed.... 相似文献
46.
Technical Physics - Experimental and theoretical data for strains arising in a single-wire copper conductor experiencing a current load are reported. The conductor has been examined under a... 相似文献
47.
Radiophysics and Quantum Electronics - The Wigner and Kirkwood functions are widely used for signal processing. We review their properties and representations. The Wigner function calculation... 相似文献
48.
Safaei Bezgabadi A. Zarandi M. Borhani Bolorizadeh M. A. 《Optical and Quantum Electronics》2021,53(3):1-20
Optical and Quantum Electronics - Classification of hyperspectral image (HSI) is widely used for the study of remotely sensed images. Convolutional Neural Networks (CNNs) are one of the most... 相似文献
49.
Alicia Cintora Florian Käfer Chenyun Yuan Christopher K. Ober 《Journal of polymer science. Part A, Polymer chemistry》2022,60(4):666-673
Activators regenerated by electron transfer (ARGET) atom transfer radical polymerization (ATRP)-based aqueous miniemulsion polymerization where the polymerization takes place in the stabilized monomer droplets is described. In this work, we compared styrene, n-butyl methacrylate (nBMA) and tert-butyl methacrylate (tBMA) and investigated the influence of their hydrophobicity on dispersity, molecular weight and particle stability based their partition coefficients (logP) (2.67, 2.23, and 1.86, respectively). Tetrabutylammonium bromide (TBAB) was used as a phase transfer agent for the controlled delivery of Cu2+-Br/tris(2-pyridylmethyl)amine (TPMA), a hydrophilic catalyst, into monomer droplets of varying hydrophobicity. The resulting dispersity and particle stability of each polymer is a function of its logP value, with the most hydrophobic monomer (styrene) displaying the narrowest dispersity and most control (Đ < 1.3), and the most hydrophilic polymer poly(tert-butyl methacrylate) (PtBMA) having reduced emulsion stability, determined by the observation of aggregate formation. Selected polymerization parameters, including effects of total ascorbic acid feed concentration and the monomer concentration and their effects on dispersity are reported. The controlled polymerizations of hydrophilic monomers using ARGET-ATRP in miniemulsion conditions and understanding the effect of monomer hydrophilicity on the emulsion stability will broaden the use of ARGET-ATRP in emulsion polymerization for the synthesis of polymer-grafted nanoparticles with hydrophilic corona. 相似文献
50.
Jared P. Klein Zachary M. Gdowski Richard A. Register 《Journal of polymer science. Part A, Polymer chemistry》2022,60(2):266-275
Though polynorbornene synthesized by ring-opening metathesis polymerization has an intrinsically all-cis configuration of the cyclopentylene backbone rings, a fraction of these rings can be epimerized to the trans configuration during hydrogenation over suitable catalysts. By varying the method of hydrogenation, semicrystalline hydrogenated polynorbornenes (hPNs) with trans levels between 0 and 36% were obtained. With increasing trans content, the glass transition temperature, melting point, and enthalpy of melting decrease modestly. By contrast, the temperature at which the hPN crystal transitions into a rotationally disordered polymorph varies strongly with trans content, ranging from 126 °C (all-cis) to 71 °C at 27% trans; at trans contents of 34% and above, no rotationally-ordered phase is observed at any temperature. The room-temperature Young's modulus shows no dependence on trans content, while the yield stress drops by 20% at 1% trans content and slowly decreases further with additional epimerization. The temperature dependence of the Young's modulus differs for trans-containing versus all-cis polymers, while the temperature dependence of the yield stress is set by the polymorph type (rotationally ordered vs. disordered). 相似文献