全文获取类型
收费全文 | 5830篇 |
免费 | 685篇 |
国内免费 | 746篇 |
专业分类
化学 | 4442篇 |
晶体学 | 76篇 |
力学 | 262篇 |
综合类 | 77篇 |
数学 | 916篇 |
物理学 | 1488篇 |
出版年
2024年 | 10篇 |
2023年 | 110篇 |
2022年 | 172篇 |
2021年 | 203篇 |
2020年 | 250篇 |
2019年 | 264篇 |
2018年 | 218篇 |
2017年 | 223篇 |
2016年 | 272篇 |
2015年 | 307篇 |
2014年 | 356篇 |
2013年 | 519篇 |
2012年 | 519篇 |
2011年 | 513篇 |
2010年 | 398篇 |
2009年 | 368篇 |
2008年 | 441篇 |
2007年 | 364篇 |
2006年 | 331篇 |
2005年 | 233篇 |
2004年 | 183篇 |
2003年 | 123篇 |
2002年 | 137篇 |
2001年 | 78篇 |
2000年 | 75篇 |
1999年 | 79篇 |
1998年 | 51篇 |
1997年 | 48篇 |
1996年 | 38篇 |
1995年 | 20篇 |
1994年 | 30篇 |
1993年 | 27篇 |
1992年 | 14篇 |
1991年 | 13篇 |
1990年 | 18篇 |
1989年 | 17篇 |
1988年 | 20篇 |
1987年 | 15篇 |
1986年 | 8篇 |
1985年 | 18篇 |
1984年 | 19篇 |
1983年 | 13篇 |
1982年 | 12篇 |
1981年 | 10篇 |
1980年 | 16篇 |
1979年 | 11篇 |
1978年 | 20篇 |
1977年 | 13篇 |
1976年 | 13篇 |
1975年 | 10篇 |
排序方式: 共有7261条查询结果,搜索用时 750 毫秒
161.
Dan Donescu Liana Fusulan Stela Lungoci Sever Serban Cristian Peteu 《Journal of Dispersion Science and Technology》2013,34(5):647-653
ABSTRACT The modification of decomposition rate of the potassium persulfate initiator during the synthesis of “two-stage latexes” polystyrene-ethyl acrylate (EtA) of butyl acrylale (BuA) and of 2-ethylhexyl acrylate (EHA) is studied. This rate is minimum for BuA and maximum for EHA, in good agreement with the value of solubility parameters. The appearance of poryacrvlaf.es determines the existence of water bonded to the polar polymer. The amount of water bonded increases in the sequence PEtA?PBuA?PEHA, function of the modification of the diameters of the particles resulted from the latexes obtained. 相似文献
162.
Wan-Yue Diao Dan Xie Yan-Fei Li Ru Jiang Fang-Yu Tao Prof. Hai-Zhu Sun Prof. Xing-Long Wu Dr. Xiao-Ying Zhang Prof. Jing-Ping Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(31):8168-8177
Lithium metal anodes (LMAs) with high energy density have recently captured increasing attention for development of next-generation batteries. However, practical viability of LMAs is hindered by the uncontrolled Li dendrite growth and infinite dimension change. Even though constructing 3D conductive skeleton has been regarded as a reliable strategy to prepare stable and low volume stress LMAs, engineering the renewable and lithiophilic conductive scaffold is still a challenge. Herein, a robust conductive scaffold derived from renewable cellulose paper, which is coated with reduced graphene oxide and decorated with lithiophilic Au nanoparticles, is engineered for LMAs. The graphene cellulose fibres with high surface area can reduce the local current density, while the well-dispersed Au nanoparticles can serve as lithiophilic nanoseeds to lower the nucleation overpotential of Li plating. The coupled relationship can guarantee uniform Li nucleation and unique spherical Li growth into 3D carbon matrix. Moreover, the natural cellulose paper possesses outstanding mechanical strength to tolerate the volume stress. In virtue of the modulated deposition behaviour and near-zero volume change, the hybrid LMAs can achieve reversible Li plating/stripping even at an ultrahigh current density of 10 mA cm−2 as evidenced by high Coulombic efficiency (97.2 % after 60 cycles) and ultralong lifespan (1000 cycles) together with ultralow overpotential (25 mV). Therefore, this strategy sheds light on a scalable approach to multiscale design versatile Li host, promising highly stable Li metal batteries to be feasible and practical. 相似文献
163.
Die Chen Dr. Shu Yang Huayi Han Lingbo Song Dr. Dan Huang Xiao Lin Dr. Xiaoping Xu Dr. Qianfan Yang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(45):11627-11632
DNA computation is considered a fascinating alternative to silicon-based computers; it has evoked substantial attention and made rapid advances. Besides realizing versatile functions, implementing spatiotemporal control of logic operations, especially at the cellular level, is also of great significance to the development of DNA computation. However, developing simple and efficient methods to restrict DNA logic gates performing in live cells is still a challenge. In this work, a series of DNA logic gates was designed by taking full advantage of the diversity and programmability of the G-quadruplex (G4) structure. More importantly, by further using the high affinity and specific endocytosis of cells to aptamer G4, an INHIBIT logic gate has been realized whose operational site is precisely restricted to specific live cells. The design strategy might have great potential in the field of molecular computation and smart bio-applications. 相似文献
164.
Manqi Ruan Hang Zhao Gang Li Chengdong Fu Zhigang Wang Xinchou Lou Dan Yu Vincent Boudry Henri Videau Vladislav Balagura Jean-Claude Brient Peizhu Lai Chia-Ming Kuo Bo Liu Fenfen An Chunhui Chen Soeren Prell Bo Li Imad Laketineh 《The European Physical Journal C - Particles and Fields》2018,78(5):426
After the Higgs discovery, precise measurements of the Higgs properties and the electroweak observables become vital for the experimental particle physics. A powerful Higgs/Z factory, the Circular Electron Positron Collider (CEPC) is proposed. The Particle Flow oriented detector design is proposed to the CEPC and a Particle Flow algorithm, Arbor is optimized accordingly. We summarize the physics object reconstruction performance of the Particle Flow oriented detector design with Arbor algorithm and conclude that this combination fulfills the physics requirement of CEPC. 相似文献
165.
166.
用浸渍法制备了改性阳离子交换树脂,通过红外光谱、热重分析和扫描电镜等对其进行了分析,探讨了不同改性树脂对以苯酚和甲醛为原料催化合成双酚F收率的影响。当等摩尔比Al Cl3和Ti Cl4加入总量为树脂质量的8%,反应温度为80℃,改性时间为10h,Al Cl3-Ti Cl4改性阳离子交换树脂催化合成双酚F,其收率高达90.02%,比未改性或Al Cl3单独改性树脂的催化效果都好,其重复利用率也优于后两者。结果说明,Al Cl3-Ti Cl4改性阳离子交换树脂催化性能好,是一种环境友好高效合成双酚F的催化剂。 相似文献
167.
The aim of this paper is to establish some stability results involving generalized divided differences. 相似文献
168.
169.
The study of the planar collisions of a rigid two-link chain with an external surface is presented. There are two points of contact during the impact process with friction, one for each link. For the normal impact, a nonlinear collision force is employed for the elasto-plastic deformation, and the Coulomb’s law models the frictional effects. The impact of the chain is studied numerically, and the results are compared with experiment data obtained from a high-speed camera. Special attention is given to simultaneous impact, slippage, and rebounds at the contact points. 相似文献
170.
Jincheng Li Huan Liu Chaoying Wang Lidong Wu Dan Liu 《Analytical and bioanalytical chemistry》2016,408(24):6537-6544