全文获取类型
收费全文 | 49141篇 |
免费 | 1636篇 |
国内免费 | 15篇 |
专业分类
化学 | 30282篇 |
晶体学 | 245篇 |
力学 | 796篇 |
综合类 | 1篇 |
数学 | 9326篇 |
物理学 | 10142篇 |
出版年
2023年 | 346篇 |
2022年 | 293篇 |
2021年 | 483篇 |
2020年 | 704篇 |
2019年 | 640篇 |
2018年 | 976篇 |
2017年 | 883篇 |
2016年 | 1764篇 |
2015年 | 1452篇 |
2014年 | 1415篇 |
2013年 | 3124篇 |
2012年 | 2979篇 |
2011年 | 2812篇 |
2010年 | 1868篇 |
2009年 | 1580篇 |
2008年 | 2463篇 |
2007年 | 2241篇 |
2006年 | 2013篇 |
2005年 | 2040篇 |
2004年 | 1794篇 |
2003年 | 1474篇 |
2002年 | 1297篇 |
2001年 | 992篇 |
2000年 | 995篇 |
1999年 | 702篇 |
1998年 | 557篇 |
1997年 | 464篇 |
1996年 | 602篇 |
1995年 | 454篇 |
1994年 | 519篇 |
1993年 | 478篇 |
1992年 | 504篇 |
1991年 | 435篇 |
1990年 | 475篇 |
1989年 | 406篇 |
1988年 | 405篇 |
1987年 | 361篇 |
1986年 | 350篇 |
1985年 | 492篇 |
1984年 | 448篇 |
1983年 | 367篇 |
1982年 | 360篇 |
1981年 | 364篇 |
1980年 | 319篇 |
1979年 | 305篇 |
1978年 | 298篇 |
1977年 | 297篇 |
1976年 | 303篇 |
1974年 | 265篇 |
1973年 | 279篇 |
排序方式: 共有10000条查询结果,搜索用时 23 毫秒
1.
2.
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
3.
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
4.
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
5.
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
6.
7.
Clemens G. Raab Georg Regensburger Jamal Hossein Poor 《Journal of Pure and Applied Algebra》2021,225(5):106564
A formal computation proving a new operator identity from known ones is, in principle, restricted by domains and codomains of linear operators involved, since not any two operators can be added or composed. Algebraically, identities can be modelled by noncommutative polynomials and such a formal computation proves that the polynomial corresponding to the new identity lies in the ideal generated by the polynomials corresponding to the known identities. In order to prove an operator identity, however, just proving membership of the polynomial in the ideal is not enough, since the ring of noncommutative polynomials ignores domains and codomains. We show that it suffices to additionally verify compatibility of this polynomial and of the generators of the ideal with the labelled quiver that encodes which polynomials can be realized as linear operators. Then, for every consistent representation of such a quiver in a linear category, there exists a computation in the category that proves the corresponding instance of the identity. Moreover, by assigning the same label to several edges of the quiver, the algebraic framework developed allows to model different versions of an operator by the same indeterminate in the noncommutative polynomials. 相似文献
8.
Tomáš Hložek Martin Štícha Miroslava Bursová Ivan Jelínek Petr Tůma Radomír Čabala 《Electrophoresis》2020,41(18-19):1564-1567
Riociguat is novel antihypertensive drug for treatment of pulmonary hypertension. As such, it is still being tested in many clinical and pharmacokinetic trials. Existing methods that determine serum riociguat and desmethylriociguat (DMR) are based solely on liquid chromatography with mass spectrometry. Therefore, we present a novel capillary electrophoresis with mass spectrometry method (CE-MS) for their determination in human serum as alternative method for ongoing trials. Complete resolution of both analytes was achieved by means of pH optimization of ammonium formate background electrolytes that are fully compatible with ESI/MS detection. Simple liquid-liquid extraction was used as sample pretreatment. The calibration dependence of the method was linear (in the range of 10–1000 ng/mL), with adequate accuracy (90.1–114.9%) and precision (13.4%). LOD and LOQ were arbitrarily set at 10 ng/mL for both analytes. Clinical applicability was validated using serum samples from patients treated with riociguat in pharmacokinetic study and the results corresponded with reference HPLC-MS/MS values. Capillary electrophoresis proved to be sensitive and selective tool for the analysis of riociguat and DMR. 相似文献
9.
Attila Kovács 《International journal of quantum chemistry》2020,120(1):e26051
Lanthanide dinitrogen complexes, Ln(N2) x (x = 1-8), were investigated by Density Functional Theory computations using the B3LYP exchange-correlation functional in conjunction with quasirelativistic pseudopotentials for Ln. After a recent study on the lanthanum complexes (A. Kovács, Structural Chemistry 2018 , 29, 1825), the present study aimed to probe the changes upon variously filled 4f subshells of Ln on the structures, stabilities, and bonding properties in related complexes of Nd, Ho, and Lu. The bonding properties were assessed on the basis of natural atomic charges, Ln valence orbital populations, and analysis of bonding molecular orbitals. 相似文献
10.