全文获取类型
收费全文 | 47589篇 |
免费 | 1635篇 |
国内免费 | 23篇 |
专业分类
化学 | 29043篇 |
晶体学 | 238篇 |
力学 | 810篇 |
数学 | 9038篇 |
物理学 | 10118篇 |
出版年
2023年 | 349篇 |
2022年 | 293篇 |
2021年 | 502篇 |
2020年 | 705篇 |
2019年 | 651篇 |
2018年 | 987篇 |
2017年 | 903篇 |
2016年 | 1761篇 |
2015年 | 1456篇 |
2014年 | 1416篇 |
2013年 | 3155篇 |
2012年 | 3007篇 |
2011年 | 2871篇 |
2010年 | 1865篇 |
2009年 | 1561篇 |
2008年 | 2449篇 |
2007年 | 2214篇 |
2006年 | 2003篇 |
2005年 | 2022篇 |
2004年 | 1753篇 |
2003年 | 1458篇 |
2002年 | 1258篇 |
2001年 | 964篇 |
2000年 | 961篇 |
1999年 | 664篇 |
1998年 | 514篇 |
1997年 | 433篇 |
1996年 | 580篇 |
1995年 | 410篇 |
1994年 | 494篇 |
1993年 | 453篇 |
1992年 | 476篇 |
1991年 | 401篇 |
1990年 | 449篇 |
1989年 | 367篇 |
1988年 | 371篇 |
1987年 | 332篇 |
1986年 | 321篇 |
1985年 | 447篇 |
1984年 | 411篇 |
1983年 | 328篇 |
1982年 | 327篇 |
1981年 | 343篇 |
1980年 | 279篇 |
1979年 | 275篇 |
1978年 | 271篇 |
1977年 | 262篇 |
1976年 | 278篇 |
1974年 | 250篇 |
1973年 | 264篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Applications of Mathematics - Proper traffic simulation of electric vehicles, which draw energy from overhead wires, requires adequate modeling of traction infrastructure. Such vehicles include... 相似文献
2.
Set-Valued and Variational Analysis - In a Hilbert framework ℌ, we study the convergence properties of a Newton-like inertial dynamical system governed by a general maximally monotone... 相似文献
3.
4.
Set-Valued and Variational Analysis - The production correspondence associated with a technology maps every input vector into the set of output vectors that may be obtained by means of those... 相似文献
5.
This review summarizes recent progress in understanding the oxygen reduction and evolution reactions at the lanthanum strontium manganite electrode of a high-temperature solid oxide cell. Information provided here is put into the perspective of the defect chemistry of lanthanum strontium manganite and its impact on the electrode reaction mechanisms itself. After summarizing recent views on the oxygen reduction reaction mechanism, the focus turns to the oxygen evolution reaction, which is significantly less treated in the literature. A combination of the information in the literature on both reactions was the basis for modified reaction mechanism of the oxygen evolution reaction to be proposed under consideration of recent experimental observations and theoretical findings. 相似文献
6.
Peralta Cecilia Mariana Acosta Gimena Henestrosa Cecilia Gil Raúl Andrés Fernández Liliana Patricia 《Journal of Analytical Chemistry》2022,77(3):308-317
Journal of Analytical Chemistry - The present development involved a flow injection strategy using a mini-column of multiwalled carbon nanotubes and fluorescent detection (λex of 283 nm,... 相似文献
7.
Dr. Yolimar Gil Dr. Alejandro Castro-Alvarez Dr. Pablo Fuentealba Prof. Evgenia Spodine Dr. Daniel Aravena 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(48):e202200336
Enhancement of axial magnetic anisotropy is the central objective to push forward the performance of Single-Molecule Magnet (SMM) complexes. In the case of mononuclear lanthanide complexes, the chemical environment around the paramagnetic ion must be tuned to place strongly interacting ligands along either the axial positions or the equatorial plane, depending on the oblate or prolate preference of the selected lanthanide. One classical strategy to achieve a precise chemical environment for a metal centre is using highly structured, chelating ligands. A natural approach for axial-equatorial control is the employment of macrocycles acting in a belt conformation, providing the equatorial coordination environment, and leaving room for axial ligands. In this review, we present a survey of SMMs based on the macrocycle belt motif. Literature systems are divided in three families (crown ether, Schiff-base and metallacrown) and their general properties in terms of structural stability and SMM performance are briefly discussed. 相似文献
8.
Dominik Vítek Prof. Aleš Růžička Lise Vermeersch Dr. Libor Dostál Dr. Jan Turek Prof. Roman Jambor 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(70):e202202639
Reactivity studies of the GeII→B complex L(Cl)Ge⋅BH3 ( 1 ; L=2-Et2NCH2-4,6-tBu2-C6H2) were performed to determine the effect on the GeII→B donation. N-coordinated compounds L(OtBu)Ge⋅BH3 ( 2 ) and [LGe⋅BH3]2 ( 3 ) were prepared. The possible tuning of the GeII→B interaction was proved experimentally, yielding compounds 1-PPh2-8-(LGe)-C10H6 ( 4 ) and L(Cl)Ge⋅GaCl3 ( 5 ) without a GeII→B interaction. In 5 , an unprecedented GeII→Ga coordination was revealed. The experimental results were complemented by a theoretical study focusing on the bonding in 1 − 5 . The different strength of the GeII→E (E=B, Ga) donation was evaluated by using energy decomposition analysis. The basicity of different L(X)Ge groups through proton affinity is also assessed. 相似文献
9.
Archiv der Mathematik - In this paper, we establish a sharp integral inequality for n-dimensional closed spacelike submanifolds with constant scalar curvature immersed with parallel normalized mean... 相似文献
10.
Bazarra Noelia Castejón Alberto Fernández José R. Quintanilla Ramón 《Meccanica》2021,56(12):3025-3037
Meccanica - In this work we study, from the numerical point of view, a one-dimensional thermoelastic problem where the thermal law is of type III. Quasi-static microvoids are also assumed within... 相似文献