全文获取类型
收费全文 | 10531篇 |
免费 | 831篇 |
国内免费 | 1273篇 |
专业分类
化学 | 3580篇 |
晶体学 | 57篇 |
力学 | 329篇 |
综合类 | 168篇 |
数学 | 6615篇 |
物理学 | 1886篇 |
出版年
2024年 | 10篇 |
2023年 | 113篇 |
2022年 | 185篇 |
2021年 | 264篇 |
2020年 | 269篇 |
2019年 | 324篇 |
2018年 | 300篇 |
2017年 | 321篇 |
2016年 | 250篇 |
2015年 | 240篇 |
2014年 | 381篇 |
2013年 | 1103篇 |
2012年 | 377篇 |
2011年 | 500篇 |
2010年 | 415篇 |
2009年 | 560篇 |
2008年 | 632篇 |
2007年 | 811篇 |
2006年 | 637篇 |
2005年 | 595篇 |
2004年 | 520篇 |
2003年 | 523篇 |
2002年 | 475篇 |
2001年 | 394篇 |
2000年 | 372篇 |
1999年 | 344篇 |
1998年 | 322篇 |
1997年 | 284篇 |
1996年 | 209篇 |
1995年 | 118篇 |
1994年 | 141篇 |
1993年 | 86篇 |
1992年 | 90篇 |
1991年 | 61篇 |
1990年 | 49篇 |
1989年 | 47篇 |
1988年 | 47篇 |
1987年 | 48篇 |
1986年 | 25篇 |
1985年 | 45篇 |
1984年 | 24篇 |
1983年 | 15篇 |
1982年 | 20篇 |
1981年 | 21篇 |
1980年 | 11篇 |
1979年 | 9篇 |
1978年 | 12篇 |
1977年 | 13篇 |
1976年 | 7篇 |
1936年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Rose Morris-Wright 《Journal of Pure and Applied Algebra》2021,225(1):106468
Parabolic subgroups are the building blocks of Artin groups. This paper extends previous results of Cumplido, Gebhardt, Gonzales-Meneses and Wiest, known only for parabolic subgroups of finite type Artin groups, to parabolic subgroups of FC-type Artin groups. We show that the class of finite type parabolic subgroups is closed under intersection. We also study an analog of the curve complex for mapping class group constructed by Cumplido et al. using parabolic subgroups. We extend the construction of this complex, called the complex of parabolic subgroups, to FC-type Artin groups. We show that this simplicial complex is, in most cases, infinite diameter and conjecture that it is δ-hyperbolic. 相似文献
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.
《Discrete Mathematics》2022,345(10):112984
Let G be a generalized dicyclic group with identity 1. An inverse closed subset S of is called minimal if and there exists some such that . In this paper, we characterize distance-regular Cayley graphs of G under the condition that S is minimal. 相似文献
4.
5.
Reza Kordnezhadian Bing-Yu Li Armir Zogu Dr. Joachim Demaerel Prof. Dr. Wim M. De Borggraeve Dr. Ermal Ismalaj 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(60):e202201491
Pentafluorosulfanyl (SF5)-containing compounds and corresponding analogs are a highly valuable class of fluorine-containing building blocks owing to their unique properties. The reason for that is the set of peculiar and tremendously beneficial characteristics they can impart on molecules once introduced onto them. Despite this, their application in distinct scientific fields remains modest, given the extremely harsh reaction conditions needed to access such compounds. The recent synthetic approaches via S−F, and C−SF5 bond formation as well as the use of SF5-containing building blocks embody a “stairway-to-heaven” loophole in the synthesis of otherwise-inaccessible chemical scaffolds only a few years ago. Herein, we report and evaluate the properties of the SF5 group and analogs, by summarizing synthetic methodologies available to access them as well as following applications in material science and medicinal chemistry since 2015. 相似文献
6.
7.
ABSTRACTThe Coupled-Cluster (CC) theory is one of the most successful high precision methods used to solve the stationary Schrödinger equation. In this article, we address the mathematical foundation of this theory with focus on the advances made in the past decade. Rather than solely relying on spectral gap assumptions (non-degeneracy of the ground state), we highlight the importance of coercivity assumptions – Gårding type inequalities – for the local uniqueness of the CC solution. Based on local strong monotonicity, different sufficient conditions for a local unique solution are suggested. One of the criteria assumes the relative smallness of the total cluster amplitudes (after possibly removing the single amplitudes) compared to the Gårding constants. In the extended CC theory the Lagrange multipliers are wave function parameters and, by means of the bivariational principle, we here derive a connection between the exact cluster amplitudes and the Lagrange multipliers. This relation might prove useful when determining the quality of a CC solution. Furthermore, the use of an Aubin–Nitsche duality type method in different CC approaches is discussed and contrasted with the bivariational principle. 相似文献
8.
9.
10.