全文获取类型
收费全文 | 1958篇 |
免费 | 39篇 |
国内免费 | 3篇 |
专业分类
化学 | 1289篇 |
晶体学 | 15篇 |
力学 | 30篇 |
数学 | 333篇 |
物理学 | 333篇 |
出版年
2022年 | 35篇 |
2021年 | 19篇 |
2020年 | 23篇 |
2019年 | 26篇 |
2018年 | 22篇 |
2017年 | 32篇 |
2016年 | 28篇 |
2015年 | 24篇 |
2014年 | 43篇 |
2013年 | 101篇 |
2012年 | 116篇 |
2011年 | 96篇 |
2010年 | 61篇 |
2009年 | 70篇 |
2008年 | 123篇 |
2007年 | 112篇 |
2006年 | 99篇 |
2005年 | 85篇 |
2004年 | 74篇 |
2003年 | 59篇 |
2002年 | 57篇 |
2001年 | 29篇 |
2000年 | 22篇 |
1999年 | 15篇 |
1997年 | 13篇 |
1996年 | 27篇 |
1995年 | 19篇 |
1994年 | 23篇 |
1993年 | 17篇 |
1992年 | 24篇 |
1991年 | 14篇 |
1990年 | 16篇 |
1989年 | 21篇 |
1988年 | 24篇 |
1987年 | 19篇 |
1986年 | 14篇 |
1985年 | 31篇 |
1984年 | 36篇 |
1983年 | 25篇 |
1982年 | 39篇 |
1981年 | 30篇 |
1980年 | 23篇 |
1979年 | 20篇 |
1978年 | 29篇 |
1977年 | 19篇 |
1976年 | 21篇 |
1974年 | 15篇 |
1973年 | 30篇 |
1972年 | 13篇 |
1971年 | 12篇 |
排序方式: 共有2000条查询结果,搜索用时 15 毫秒
81.
82.
83.
84.
Synthesis of methyl 2-(3′-methoxy-4′-methylphenyl)-propionate via the T1(NO3)3-induced oxidative rearrangement of 3′-methoxy-4′-methylpropiophenone. 相似文献
85.
86.
N‐bromo‐hydantoin grafted polystyrene beads: Synthesis and nano‐micro beads characteristics for achieving controlled release of active oxidative bromine and extended microbial inactivation efficiency 下载免费PDF全文
Mahran Daif Konda Reddy Kunduru Natalia Laout Stanislav Ratner Nurit Beyth Abraham J. Domb 《Journal of polymer science. Part A, Polymer chemistry》2016,54(5):596-610
N‐bromo‐hydantoin and N‐bromo‐5,5′‐dimethylhydantoin conjugated polystyrene beads were synthesized from chloromethyl polystyrene beads which differ in their particles size, crosslinking, nano‐micro porosity, and tunnels size on the surface, in order to study the effect of these parameters on oxidative halogen release and resultant activity, for water purification applications. The synthesized beads were characterized using elemental analysis, FT‐IR, solid state 13C‐NMR, and scanning electron microscope (SEM). The conjugation yield and kinetics in different solvents and bromine loading capacity were studied. The N‐bromoamine polystyrene beads were tested for water decontamination according to NSF 231 protocol. The release of active bromine was analyzed by spectrophotometer using a DPD‐1 kit and also studied the antimicrobial activity against Escherichia coli and MS2 phages. Bead's nano‐micro characteristics were found critical for oxidative halogen release control: rate stabilization and modulation, extension and also influences antimicrobial activity. The synthesized beads exhibited extended and stable release of bromine, 6 and 4 log reduction for E. coli and MS2, respectively for 250 L of passing contaminated water. Thus, N‐halamine hydantoins conjugated polystyrenes, chemically or kinetically release modified should have applications as disinfectants in water purification systems as well as medical field. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 596–610 相似文献
87.
Florent Jasinski Emeline Lobry Lénaïg Lefevre Abraham Chemtob Céline Croutxe‐Barghorn Xavier Allonas Adrien Criqui 《Journal of polymer science. Part A, Polymer chemistry》2014,52(13):1843-1853
The use of UV light to initiate emulsion polymerization processes is generally overlooked, whilst extensive literature exists on photocuring of monomer films. In this study, the unique potential of UV light to produce at ambient temperature polyacrylate latexes without initiator was exploited. Although radical initiators are utilized at low concentration, their cost, toxicity, and odor provide incentives for finding alternatives. Starting with concentrated (30 wt %) and low scattering acrylate miniemulsions (droplet diameter <100 nm), it was demonstrated that acrylate self‐initiation can promote an efficient and fast photopolymerization in micrometer‐scale reactor (spectrophotometric cell) and lab‐scale photoreactor. Herein, all kinetic, colloidal, and mechanistic aspects involved in the self‐initiation of acrylate miniemulsion were extensively examined to provide a complete picture. In particular, the effects of droplet size, initiating wavelength, optical path, and irradiance on the course of the polymerization were thoroughly discussed. A diradical self‐initiation pathway is the most likely mechanism. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1843–1853 相似文献
88.
Ester Abtew Abraham J. Domb Arijit Basu 《Journal of polymer science. Part A, Polymer chemistry》2017,55(16):2657-2662
We report on the synthesis of polypeptides with saccharide side chains starting from d ‐glucosaminic acid. The hydroxyl groups were first protected by benzylation, followed by N‐carboxyanhydride formation, which was polymerized by ring opening to form a high molecular weight polyamide. De‐protection of the benzyl groups yields a polypeptide with fully de‐protected saccharide side chains. The resulting new non‐ionic, water soluble, and optically active polymers possessing the properties of both peptides and saccharides have potential use as scaffolds for tissue engineering and drug carriers. The method described here may be extended to any saccharide α‐amino acid. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2657–2662 相似文献
89.
Yixuan Xie Chao Peng Yunyi Gao Xiaohong Liu Tianbo Liu Abraham Joy 《Journal of polymer science. Part A, Polymer chemistry》2017,55(23):3908-3917
Glycopolymers have been widely used to understand the interactions between carbohydrates and lectins, which facilitate the diagnosis and detection of disease and pathogens as well as the development of vaccines. While studies have been focused on the correlation of glycopolymer structure and their binding to lectins, graft‐type glycopolyesters are uncommon. Herein, we report the design and synthesis of mannose‐based graft polyesters by “grafting‐from” method and investigate their interactions with Concanavalin A (Con A). As confirmed by 1H NMR spectroscopy and sulfuric acid‐UV method, graft polyesters with different lengths of mannose graft were successfully synthesized. Our results from turbidimetry binding assay showed that graft polyesters with longer mannose graft exhibit higher initial binding rate (ki). Isothermal titration calorimetry measurements of these graft polyesters with Con A showed that polymers exhibit higher binding affinity (ka) with the number of side chain mannose. This study provides understanding of the interaction between Con A and mannose‐based graft polyesters, which can be employed for the development of glycopolymeric therapeutics. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3908–3917 相似文献
90.