全文获取类型
收费全文 | 1428篇 |
免费 | 38篇 |
国内免费 | 2篇 |
专业分类
化学 | 854篇 |
晶体学 | 64篇 |
力学 | 46篇 |
数学 | 191篇 |
物理学 | 313篇 |
出版年
2022年 | 15篇 |
2021年 | 10篇 |
2020年 | 13篇 |
2019年 | 12篇 |
2018年 | 19篇 |
2017年 | 20篇 |
2016年 | 27篇 |
2015年 | 26篇 |
2014年 | 35篇 |
2013年 | 114篇 |
2012年 | 69篇 |
2011年 | 83篇 |
2010年 | 42篇 |
2009年 | 44篇 |
2008年 | 75篇 |
2007年 | 67篇 |
2006年 | 73篇 |
2005年 | 59篇 |
2004年 | 47篇 |
2003年 | 47篇 |
2002年 | 34篇 |
2001年 | 25篇 |
2000年 | 25篇 |
1999年 | 10篇 |
1997年 | 19篇 |
1996年 | 13篇 |
1995年 | 13篇 |
1994年 | 14篇 |
1993年 | 17篇 |
1992年 | 15篇 |
1990年 | 10篇 |
1989年 | 13篇 |
1988年 | 16篇 |
1987年 | 18篇 |
1986年 | 18篇 |
1985年 | 15篇 |
1984年 | 26篇 |
1983年 | 10篇 |
1982年 | 30篇 |
1981年 | 11篇 |
1980年 | 12篇 |
1979年 | 14篇 |
1978年 | 13篇 |
1977年 | 20篇 |
1976年 | 16篇 |
1975年 | 20篇 |
1974年 | 13篇 |
1973年 | 15篇 |
1971年 | 11篇 |
1959年 | 11篇 |
排序方式: 共有1468条查询结果,搜索用时 15 毫秒
91.
Ramajayam Govindan Mohamed El-Sherbiny Khalid Mohamed Morsy Ibraheem Srinivasan Narasimhan Mohamed EL-Dosoky Mohamed Salama Fazil Ahmad Selvaraj Jayaraman Vishnu Priya Veeraraghavan Srinivasan Vengadassalapathy Surapaneni Krishna Mohan Vidhya Rekha Umapathy Gayathri Rengasamy Shazia Fathima Jaffer Hussain Maheshkumar Poomarimuthu Senthilkumar Kalimuthu 《Molecules (Basel, Switzerland)》2022,27(3)
92.
Abstract: Reaction of a number of alkyl halides with tetrathiomolybdate in water as the solvent affords the corresponding disulfides in good yields. 相似文献
93.
Singh Ajit Srinivasan Palaniappan Putcha Uday Kumar Perikati Madhusudhanachary 《Journal of polymer science. Part A, Polymer chemistry》2012,50(5):884-889
Porphyrins are very important chromophores as sensitizer in solar cell. Hole and electron transport layers are being used as an important layer to move the electrons and holes away from the sensitizer molecule to electrodes. In this work, a simple process has been developed for the synthesis of one layer combination of sensitizer and hole transport, that is, polyaniline‐porphyrin (PANI‐TPPS4) system as a bulk heterojunction. Macrospheres of fluorescent PANI‐TPPS4 materials were synthesized by one‐pot as well as two step processes directly from porphyrin for the first time. The advantage of this process is no need to isolate sulfonated porphyrin (TPPS4), which is a difficult process. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
94.
Selvam Noyel Victoria Srinivasan Ramanathan 《Journal of Solid State Electrochemistry》2011,15(4):837-844
The effect of l-glutamic acid as complexing agent in the presence of hydrogen peroxide as oxidizer in copper chemical mechanical polishing
(CMP) slurry is investigated. In the CMP process, the work surface is moved against a pad, with slurry flowing between the
surface and the pad. The polish rate was found to be stable over a wide range of hydrogen peroxide concentration. High concentration
of either l-glutamic acid or hydrogen peroxide leads to a reduction in polish rate, but a high concentration of both chemicals does not
reduce the polish rate. In the absence of hydrogen peroxide, the Cu polish rate was 0 for all the l-glutamic acid concentrations investigated. However, potentiodynamic polarization curves do not show any sign of passivation
when l-glutamic acid was present in the solution. In situ open circuit potential measurements show that copper redox reactions as
well as hydrogen peroxide redox reactions contribute in determining the electrochemical behavior. We propose that l-glutamic acid inhibits the copper dissolution by adsorption onto the metallic copper, but enhances copper dissolution by
complexing copper ions. The results show that it is possible to conduct controllable copper CMP in mildly acidic slurries
with hydrogen peroxide as oxidizer and l-glutamic acid as complexing agent. 相似文献
95.
96.
This article presents the study of singularly perturbed parabolic reaction–diffusion problems with boundary layers. To solve these problems, we use a modified backward Euler finite difference scheme on layer adapted nonuniform meshes at each time level. The nonuniform meshes are obtained by equidistribution of a positive monitor function, which involves the second-order spatial derivative of the singular component of the solution. The equidistributing monitor function at each time level allows us to use this technique to non-linear parabolic problems. The truncation error and the stability analysis are obtained. Parameter–uniform error estimates are derived for the numerical solution. To support the theoretical results, numerical experiments are carried out. 相似文献
97.
98.
Gautam Gundiah M Eswaramoorthy S Neeraj Srinivasan Natarajan C N R Rao 《Journal of Chemical Sciences》2001,113(3):227-234
Mesoporous aluminosilicate spheres of 0.3–0.4 Μm diameter, with different Si/Al ratios, have been prepared by surfactant templating.
Surface area of these materials is in the 510–970 m2 g-1 range and pore diameter in the 15–20 ? range. 相似文献
99.
100.
[reaction: see text] Synthesis and structure of a novel [6.6]metacyclophane with enediyne bridges is reported. 相似文献