全文获取类型
收费全文 | 175139篇 |
免费 | 3098篇 |
国内免费 | 1578篇 |
专业分类
化学 | 91922篇 |
晶体学 | 2497篇 |
力学 | 7504篇 |
综合类 | 70篇 |
数学 | 20182篇 |
物理学 | 57640篇 |
出版年
2021年 | 1454篇 |
2020年 | 1776篇 |
2019年 | 1913篇 |
2018年 | 2270篇 |
2017年 | 2319篇 |
2016年 | 3511篇 |
2015年 | 2257篇 |
2014年 | 3494篇 |
2013年 | 8133篇 |
2012年 | 6332篇 |
2011年 | 7423篇 |
2010年 | 5384篇 |
2009年 | 5368篇 |
2008年 | 6950篇 |
2007年 | 6805篇 |
2006年 | 6390篇 |
2005年 | 5788篇 |
2004年 | 5277篇 |
2003年 | 4774篇 |
2002年 | 4633篇 |
2001年 | 5377篇 |
2000年 | 4004篇 |
1999年 | 3074篇 |
1998年 | 2367篇 |
1997年 | 2315篇 |
1996年 | 2135篇 |
1995年 | 2114篇 |
1994年 | 2101篇 |
1993年 | 1990篇 |
1992年 | 2263篇 |
1991年 | 2199篇 |
1990年 | 2153篇 |
1989年 | 2074篇 |
1988年 | 2076篇 |
1987年 | 2073篇 |
1986年 | 1974篇 |
1985年 | 2594篇 |
1984年 | 2639篇 |
1983年 | 2329篇 |
1982年 | 2449篇 |
1981年 | 2253篇 |
1980年 | 2236篇 |
1979年 | 2398篇 |
1978年 | 2433篇 |
1977年 | 2376篇 |
1976年 | 2423篇 |
1975年 | 2345篇 |
1974年 | 2312篇 |
1973年 | 2485篇 |
1972年 | 1602篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Kinetics and Catalysis - The results of studies in the field of synthesis and characterization of layered double hydroxides (LDHs) obtained using solid-phase reactions are summarized. The effect of... 相似文献
2.
Petrov P. A. Filippova E. A. Kompankov N. B. Sukhikh T. S. Sokolov M. N. 《Journal of Structural Chemistry》2022,63(3):470-475
Journal of Structural Chemistry - A new polymorph of the [ReCl3(MeCN)(PPh3)2] complex is synthesized and characterized by single crystal X-ray diffraction (XRD). Its recrystallization from the... 相似文献
3.
Tsyganova S. I. Fetisova O. Yu. Mazurova E. N. Taran O. P. Kuznetsov B. N. 《Russian Journal of Applied Chemistry》2022,95(3):408-416
Russian Journal of Applied Chemistry - A method for the disposal of hydrolysis lignin waste based on its modification with ZnCl2 and FeCl3 and subsequent carbonization at 800°C was proposed.... 相似文献
4.
Roopa K. P. Keshavamurthy K. Mahesh B. Veena K. P. Shankara B. S. Basavaiah K. 《Journal of Applied Spectroscopy》2022,89(4):809-818
Journal of Applied Spectroscopy - Three simple, sensitive, precise, and rapid spectrophotometric methods are developed and optimized for the assay of vardenafil in pharmaceutical formulations. The... 相似文献
5.
Varfolomeev S. D. Panin A. A. Semenova N. A. Ublinskiy M. V. Akhadov T. A. Bykov V. I. Tsybenova S. B. 《Russian Chemical Bulletin》2022,71(3):591-594
A kinetic study of the effect of thermoheliox (inhalation of a helium and oxygen mixture, 70 °C) on the functional hemodynamics of the human brain by functional magnetic resonance imaging was carried out. The dynamic responses of the BOLD signal were found to be biphasic. An empirical equation describing the first phase of the hemodynamic response to visual stimulus was proposed. It was shown that preliminary inhalation of thermoheliox stimulates the hemodynamic responses by slowing down the vasoconstriction.
相似文献6.
Schmalian Misha Suris Yuri B. Tumarkin Yuriy 《Mathematical Physics, Analysis and Geometry》2021,24(4):1-17
Mathematical Physics, Analysis and Geometry - In this paper, we develop the dressing method to study the modified Camassa-Holm equation with the help of reciprocal transformation and the associated... 相似文献
7.
Karandashev S. A. Lukhmyrina T. S. Matveev B. A. Remennyi M. A. Usikova A. A. 《Optics and Spectroscopy》2021,129(11):1231-1235
Optics and Spectroscopy - The current–voltage characteristics and photocurrent of “monolithic” diode optical pairs optically coupled by a substrate made of InAs common for them... 相似文献
8.
JETP Letters - Extraordinary multiparticle effects in quantizing magnetic fields that are manifested in strongly interacting two-dimensional electron systems in MgZnO/ZnO heterostructures have been... 相似文献
9.
Algebra and Logic - Unary functions definable in o-stable ordered groups of nonvaluational type are studied. Such functions are proved to be piecewise monotone and continuous. 相似文献
10.
A numerical model was developed and validated to investigate the fluid–structure interactions between fully developed pipe flow and core–shell-structured microcapsule in a microchannel. Different flow rates and microcapsule shell thicknesses were considered. A sixth-order rotational symmetric distribution of von Mises stress over the microcapsule shell can be observed on the microcapsule with a thinner shell configuration, especially at higher flow rate conditions. It is also observed that when being carried along in a fully developed pipe flow, the microcapsule with a thinner shell tends to accumulate stress at a higher rate compared to that with a thicker shell. In general, for the same microcapsule configuration, higher flow velocity would induce a higher stress level over the microcapsule shell. The deformation gradient was used to capture the microcapsule's deformation in the present study. The effect of Young's modulus on the microcapsule shell on the microcapsule deformation was investigated as well. Our findings will shed light on the understanding of the stability of core–shell-structured microcapsule when subjected to flow-induced shear stress in a microfluidic system, enabling a more exquisite control over the breakup dynamics of drug-loaded microcapsule for biomedical applications. 相似文献