全文获取类型
收费全文 | 1815篇 |
免费 | 157篇 |
国内免费 | 106篇 |
专业分类
化学 | 1169篇 |
晶体学 | 24篇 |
力学 | 82篇 |
综合类 | 8篇 |
数学 | 386篇 |
物理学 | 409篇 |
出版年
2023年 | 29篇 |
2022年 | 69篇 |
2021年 | 63篇 |
2020年 | 61篇 |
2019年 | 70篇 |
2018年 | 64篇 |
2017年 | 61篇 |
2016年 | 99篇 |
2015年 | 81篇 |
2014年 | 95篇 |
2013年 | 127篇 |
2012年 | 119篇 |
2011年 | 141篇 |
2010年 | 89篇 |
2009年 | 71篇 |
2008年 | 86篇 |
2007年 | 74篇 |
2006年 | 79篇 |
2005年 | 69篇 |
2004年 | 49篇 |
2003年 | 32篇 |
2002年 | 33篇 |
2001年 | 20篇 |
2000年 | 27篇 |
1999年 | 23篇 |
1998年 | 16篇 |
1997年 | 22篇 |
1996年 | 26篇 |
1995年 | 28篇 |
1994年 | 18篇 |
1993年 | 16篇 |
1992年 | 21篇 |
1991年 | 20篇 |
1990年 | 11篇 |
1989年 | 5篇 |
1987年 | 9篇 |
1986年 | 10篇 |
1985年 | 15篇 |
1984年 | 14篇 |
1983年 | 11篇 |
1982年 | 9篇 |
1981年 | 12篇 |
1980年 | 8篇 |
1979年 | 4篇 |
1978年 | 10篇 |
1977年 | 12篇 |
1976年 | 10篇 |
1975年 | 8篇 |
1974年 | 8篇 |
1973年 | 10篇 |
排序方式: 共有2078条查询结果,搜索用时 15 毫秒
921.
Andrei Hutanu David Boelsterli Claudio Schmidli Cristina Montealegre Mike H. N. Dang Thai Balazs Bobaly Marius Koch Maria A. Schwarz 《Electrophoresis》2022,43(9-10):1107-1117
With recent FDA approval of two recombinant adeno-associated virus (rAAV)-based gene therapies, these vectors have proven that they are suitable to address monogenic diseases. However, rAAVs are relatively new modalities, and their production and therapy costs significantly exceed those of conventional biologics. Thus, significant efforts are made to improve the processes, methods, and techniques used in manufacturing and quality control (QC). Here, we evaluate transmission electron microscopy (TEM), analytical ultracentrifugation (AUC), and two modes of capillary electrophoresis (CE) for their ability to analyze the DNA encapsidated by rAAVs. While TEM and AUC are well-established methods for rAAV, capillary gel electrophoresis (CGE) has been just recently proposed for viral genome sizing. The data presented reflect that samples are very complex, with various DNA species incorporated in the virus, including small fragments as well as DNA that is larger than the targeted transgene. CGE provides a good insight in the filling of rAAVs, but the workflow is tedious and the method is not applicable for the determination of DNA titer, since a procedure for the absolute quantification (e.g., calibration) is not yet established. For estimating the genome titer, we propose a simplified capillary zone electrophoresis approach with minimal sample preparation and short separation times (<5 min/run). Our data show the benefits of using the four techniques combined, since each of them alone is prone to delivering ambiguous results. For this reason, a clear view of the rAAV interior can only be provided by using several analytical methods simultaneously. 相似文献
922.
Polymer coating of graphene oxide via reversible addition–fragmentation chain transfer mediated emulsion polymerization
下载免费PDF全文
![点击此处可从《Journal of polymer science. Part A, Polymer chemistry》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Vien T. Huynh Duc Nguyen Christopher H. Such Brian S. Hawkett 《Journal of polymer science. Part A, Polymer chemistry》2015,53(12):1413-1421
This work describes a versatile method to encapsulate graphene oxide (GO) with polymers using reversible addition‐fragmentation chain transfer (RAFT) mediated emulsion polymerization. A living low molecular weight anionic macro‐RAFT statistical copolymer of sodium styrene sulfonate, acrylic acid, and butyl acrylate (BA) was synthesized using 2‐{[(butylsulfanyl)carbonothioyl] sulfanyl} propanoic acid as the chain transfer agent. GO was dispersed in water by pretreating the surface with poly(allylamine hydrochloride) (PAH), before being stabilized by the addition of the anionic macro‐RAFT copolymer. PAH was used to facilitate the adsorption of the macro‐RAFT copolymer to the GO surface via electrostatic attraction between opposite charges. The dispersed GO sheets were encapsulated with polymer by the free radical emulsion polymerization of methyl methacrylate and BA under starved fed conditions. The polymer shells encapsulating the GO sheets were formed by the chain extension of the adsorbed living macro‐RAFT copolymer. TEM, SEM, FTIR, and AFM were used to confirm the presence of the polymer layer on the surface of the GO. The thickness of the polymer coating can be adjusted by controlling the amount of monomer fed into the system. Partial polymer coatings of the GO could be achieved by varying the amount of PAH. The encapsulated GO was found to be easily dispersed in both aqueous and organic solvents over a range of polarities. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1413–1421 相似文献
923.
924.
925.
926.
Xiaoqian Ge Lining Sun Song Dang Jinliang Liu Yanxia Xu Zuwu Wei Liyi Shi Hongjie Zhang 《Mikrochimica acta》2015,182(9-10):1653-1660
927.
928.
929.
930.
Chuang-yin Dang 《计算数学(英文版)》2006,24(6):711-718
A mapping f:Z~n→R~n is said to possess the direction preserving property if fi(x)>0implies fi(y)≥0 for any integer points x and y with ‖x-y‖∞≤1.In this paper,a simplicial algorithm is developed for computing an integer zero point of a mappingwith the direction preserving property.We assume that there is an integer point x~0 withc≤x~0≤d satisfying that max_(1≤i≤n)(x_i-x_i~0)fi(x)>0 for any integer point x withf(x)≠0 on the boundary of H={x∈R~n|c-e≤x≤d e},where c and d are twofinite integer points with c≤d and e=(1,1,…1)~∈R~n.This assumption is impliedby one of two conditions for the existence of an integer zero point of a mapping with thepreserving property in van der Laan et al.(2004).Under this assumption, starting at x~0,the algorithm follows a finite simplicial path and terminates at an integer zero point ofthe mapping.This result has applications in general economic equilibrium models withindivisible commodities. 相似文献