全文获取类型
收费全文 | 67709篇 |
免费 | 1868篇 |
国内免费 | 363篇 |
专业分类
化学 | 39787篇 |
晶体学 | 326篇 |
力学 | 1709篇 |
综合类 | 6篇 |
数学 | 11926篇 |
物理学 | 16186篇 |
出版年
2022年 | 389篇 |
2021年 | 599篇 |
2020年 | 830篇 |
2019年 | 686篇 |
2018年 | 787篇 |
2017年 | 801篇 |
2016年 | 1663篇 |
2015年 | 1404篇 |
2014年 | 1556篇 |
2013年 | 3294篇 |
2012年 | 3151篇 |
2011年 | 3598篇 |
2010年 | 2205篇 |
2009年 | 1861篇 |
2008年 | 3253篇 |
2007年 | 3135篇 |
2006年 | 3132篇 |
2005年 | 2817篇 |
2004年 | 2571篇 |
2003年 | 2112篇 |
2002年 | 1966篇 |
2001年 | 1304篇 |
2000年 | 1103篇 |
1999年 | 877篇 |
1998年 | 804篇 |
1997年 | 843篇 |
1996年 | 912篇 |
1995年 | 819篇 |
1994年 | 881篇 |
1993年 | 848篇 |
1992年 | 877篇 |
1991年 | 703篇 |
1990年 | 675篇 |
1989年 | 634篇 |
1988年 | 595篇 |
1987年 | 557篇 |
1986年 | 561篇 |
1985年 | 861篇 |
1984年 | 844篇 |
1983年 | 717篇 |
1982年 | 778篇 |
1981年 | 738篇 |
1980年 | 756篇 |
1979年 | 672篇 |
1978年 | 697篇 |
1977年 | 673篇 |
1976年 | 590篇 |
1975年 | 541篇 |
1974年 | 542篇 |
1973年 | 466篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
The field of medicinal inorganic chemistry is rapidly advancing. In particular organometallic complexes have much potential as therapeutic and diagnostic agents. The carbon‐bound and other ligands allow the thermodynamic and kinetic reactivity of the metal ion to be controlled and also provide a scaffold for functionalization. The establishment of structure–activity relationships and elucidation of the speciation of complexes under conditions relevant to drug testing and formulation are crucial for the further development of promising medicinal applications of organometallic complexes. Specific examples involving the design of ruthenium and osmium arene complexes as anticancer agents are discussed. 相似文献
142.
143.
144.
Andrew C. Brooks Peter Day John D. Wallis 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(5):o245-o247
The crystal structure of the title compound [systematic name: 2‐(1,3‐dithiolo[4,5‐b][1,4]dithiin‐2‐ylidene)‐6,6‐bis(methoxyethoxymethoxymethyl)‐1,3‐dithiolo[4,5‐b][1,4]dithiepine], C21H30O6S8, a spiro‐substituted BEDT–TTF analogue [BEDT–TTF is bis(ethylenedithio)tetrathiafulvalene], has a strongly bent heterocyclic framework. The seven‐membered ring adopts a pseudo‐chair conformation with notably widened ring bond angles, especially at the methylene C atoms [119.49 (11) and 117.60 (11)°]. The axial side chain adopts an extended conformation, but the equatorial side chain curls back on itself and the O atom nearest the ring system is involved in three short contacts to H atoms (2.45–2.53 Å). The molecules pack in centrosymmetrically related pairs, which are isolated from each other by columns of the polyether side chains. This study emphasizes the ease of distortion of the neutral bis(propylenedithio)tetrathiafulvalene ring structure, and how the need to accommodate side chains can easily override the tendency of these donor systems to form stacks in the crystalline state. 相似文献
145.
146.
An explicit derivation of dispersion relations and spectra for periodic Schrödinger operators on carbon nano-structures (including graphene and all types of single-wall nano-tubes) is provided. 相似文献
147.
Jessica Strömbro Peter Gudmundson 《International Journal of Solids and Structures》2008,45(22-23):5765-5787
In this paper a simplified network model for mechano-sorptive creep is presented, which is a further development of an earlier paper [Strömbro, J., Gudmundson, P., 2008. Mechano-sorptive creep under compressive loading – a micromechanical model. International Journal of Solids and Structures 45 (9), 2420–2450.]. It is assumed that the anisotropic hygroexpansion of the fibres leads to large stresses at the fibre bonds when the moisture content changes. The resulting stress state will accelerate creep if the fibre material obeys a constitutive law that is non-linear. Fibre kinks are included in order to capture experimental observations of larger mechano-sorptive effects in compression than in tension. Moisture dependent material parameters and anisotropy in the fibre distribution have been introduced. Theoretical predictions based on the model are compared to experimental results for an anisotropic paper both under tensile and compressive loading at varying moisture content and it is found that the important features in the experiments are captured by the model. Different kinds of drying conditions have also been examined. 相似文献
148.
Periodica Mathematica Hungarica - 相似文献
149.
András Sütő 《Journal of statistical physics》2003,112(1-2):375-396
We study condensation of trapped bosons in the limit when the number of particles tends to infinity. For the noninteracting gas we prove that there is no phase transition in any dimension, but in any dimension, at any temperature the system is 100% condensated into the one-particle ground state. In the case of an interacting gas we show that for a family of suitably scaled pair interactions, the Gross–Pitaevskii scaling included, a less-than-100% condensation into a single-particle eigenstate, which may depend on the interaction strength, persists at all temperatures. 相似文献
150.