全文获取类型
收费全文 | 15240篇 |
免费 | 554篇 |
国内免费 | 19篇 |
专业分类
化学 | 9154篇 |
晶体学 | 137篇 |
力学 | 310篇 |
综合类 | 2篇 |
数学 | 2912篇 |
物理学 | 3298篇 |
出版年
2023年 | 119篇 |
2022年 | 121篇 |
2021年 | 207篇 |
2020年 | 250篇 |
2019年 | 245篇 |
2018年 | 318篇 |
2017年 | 322篇 |
2016年 | 595篇 |
2015年 | 524篇 |
2014年 | 569篇 |
2013年 | 1031篇 |
2012年 | 932篇 |
2011年 | 1065篇 |
2010年 | 653篇 |
2009年 | 566篇 |
2008年 | 729篇 |
2007年 | 711篇 |
2006年 | 553篇 |
2005年 | 424篇 |
2004年 | 393篇 |
2003年 | 392篇 |
2002年 | 344篇 |
2001年 | 210篇 |
2000年 | 201篇 |
1999年 | 169篇 |
1998年 | 148篇 |
1997年 | 154篇 |
1996年 | 162篇 |
1995年 | 131篇 |
1994年 | 129篇 |
1993年 | 120篇 |
1992年 | 135篇 |
1991年 | 103篇 |
1990年 | 115篇 |
1989年 | 98篇 |
1988年 | 110篇 |
1987年 | 99篇 |
1985年 | 128篇 |
1984年 | 140篇 |
1983年 | 107篇 |
1982年 | 114篇 |
1981年 | 116篇 |
1980年 | 114篇 |
1979年 | 118篇 |
1978年 | 113篇 |
1977年 | 101篇 |
1976年 | 130篇 |
1975年 | 106篇 |
1974年 | 117篇 |
1973年 | 90篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
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
2.
Verdecho María-José Alarcón-Valero Faustino Pérez-Perales David Alfaro-Saiz Juan-José Rodríguez-Rodríguez Raúl 《Central European Journal of Operations Research》2021,29(4):1231-1251
Central European Journal of Operations Research - Sustainability practice within supply chains remains in an early development phase. Enterprises still need tools that support the integration of... 相似文献
3.
Zakrajšek Srečko Rajkovič Vladislav Bernik Mojca Jereb Eva Rajkovič Uroš 《Central European Journal of Operations Research》2021,29(3):841-857
Central European Journal of Operations Research - Digital competences are among the most important competences in modern society, with the education system playing a key role in the acquisition of... 相似文献
4.
5.
6.
7.
8.
Sergio Ayala‐Mar Javier Donoso‐Quezada Roberto C. Gallo‐Villanueva Victor H. Perez‐Gonzalez Jos Gonzlez‐Valdez 《Electrophoresis》2019,40(23-24):3036-3049
Exosomes are nanovesicles secreted by most cellular types that carry important biochemical compounds throughout the body with different purposes, playing a preponderant role in cellular communication. Because of their structure, physicochemical properties and stability, recent studies are focusing in their use as nanocarriers for different therapeutic compounds for the treatment of different diseases ranging from cancer to Parkinson's disease. However, current bioseparation protocols and methodologies are selected based on the final exosome application or intended use and present both advantages and disadvantages when compared among them. In this context, this review aims to present the most important technologies available for exosome isolation while discussing their advantages and disadvantages and the possibilities of being combined with other strategies. This is critical since the development of novel exosome‐based therapeutic strategies will be constrained to the effectiveness and yield of the selected downstream purification methodologies for which a thorough understanding of the available technological resources is needed. 相似文献
9.
Periodica Mathematica Hungarica - We present a tight parametrical Hermite–Hadamard type inequality with probability measure, which yields a considerably closer upper bound for the mean value... 相似文献
10.
Nováková Kateřina Hrdlička Vojtěch Navrátil Tomáš Vyskočil Vlastimil Barek Jiří 《Monatshefte für Chemie / Chemical Monthly》2015,146(5):761-769
Monatshefte für Chemie - Chemical Monthly - The voltammetric behavior of 5-nitroindazole was investigated at polished (p-AgSAE) and at mercury meniscus-modified (m-AgSAE) silver solid amalgam... 相似文献