全文获取类型
收费全文 | 175篇 |
免费 | 10篇 |
国内免费 | 3篇 |
专业分类
化学 | 105篇 |
晶体学 | 1篇 |
力学 | 17篇 |
数学 | 36篇 |
物理学 | 29篇 |
出版年
2023年 | 3篇 |
2022年 | 7篇 |
2021年 | 11篇 |
2020年 | 3篇 |
2019年 | 7篇 |
2018年 | 5篇 |
2017年 | 1篇 |
2016年 | 6篇 |
2015年 | 3篇 |
2014年 | 13篇 |
2013年 | 21篇 |
2012年 | 8篇 |
2011年 | 17篇 |
2010年 | 9篇 |
2009年 | 7篇 |
2008年 | 14篇 |
2007年 | 11篇 |
2006年 | 10篇 |
2005年 | 6篇 |
2004年 | 7篇 |
2003年 | 4篇 |
2002年 | 1篇 |
2000年 | 1篇 |
1998年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1990年 | 1篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1981年 | 1篇 |
排序方式: 共有188条查询结果,搜索用时 109 毫秒
61.
Mesut Gorur Faruk Yilmaz Adem Kilic Zeynep M. Sahin Ali Demirci 《Journal of polymer science. Part A, Polymer chemistry》2011,49(14):3193-3206
Novel hexa‐armed and pyrene (Pyr) end‐capped phosphazene dendrimer [N3P3‐(Pyr)6] and star polymer with poly(ε‐caprolactone) (PCL) arms [N3P3‐(PCL‐Pyr)6] were prepared via two series of reactions. In these series, core‐first approach was used starting from a hexa‐hydroxy functional phosphazene derivative (N3P3‐(OH)6). It was used as an initiator in the ring‐opening polymerization of ε‐caprolactone to prepare a hexa‐armed PCL star polymer (N3P3‐(PCL‐OH)6). Hydroxyl functionalities of N3P3‐(OH)6 and N3P3‐(PCL‐OH)6 were then successfully converted into bromide and azide, in turn. Further end‐group modifications of azide functional dendrimer precursor (N3P3‐(N3)6) and star polymer (N3P3‐(PCL‐N3)6) were achieved quantitatively via the Cu(I) catalyzed click reaction between azide functional groups and 1‐ethynyl pyrene in the final step. Moreover, the pyrene end‐capped phosphazene dendrimer and star polymer were used in noncovalent functionalization of multiwalled carbon nanotubes. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
62.
Asuman Celik Kucuk Faruk Yilmaz Hatice Can Hakan Durmaz Arif Kosemen Ali Ekrem Muftuoglu 《Journal of polymer science. Part A, Polymer chemistry》2011,49(19):4180-4192
Synthesis of a novel macroinimer comprising poly(ε‐caprolactone) (PCL) and thiophene (Th) and its use in electrochromic device (ECD) application have been reported. First, a novel Th monomer ( 5 ) with miktofuntional initiator groups (primary hydroxyl and tertiary bromide at the third position of the thiophene ring) was synthesized in a four‐step reaction sequence. Density functional theory‐predicted bond lengths, angles, and vibrations of 5 were in good agreement with available experimental vibrational spectra. Subsequently, ring‐opening polymerization of ε‐caprolactone (ε‐CL) was carried out in bulk using 5 as the initiator and tin(II) 2‐ethylhexanoate (Sn(Oct)2) as the catalyst at 115 °C, which led to α‐thiophene end‐capped PCL macroinimer (PCL‐Th). Furthermore, PCL‐Th macroinimer was used in electrochemical copolymerization with pyrrole (Py) and Th. PCL‐Th/PTh copolymer film synthesized on indium tin oxide‐coated glass slide showed electrochromic behavior. Optical analyses of the PCL‐Th/PTh copolymer film indicated that the copolymer film was suitable to be used as an anodically coloring material for ECD applications. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
63.
Abstract. An accurate analytical interpretation method to determine the Leverett function (fw)and its derivative (fw) from immiscible displacement data in core plugs is presented. Linear equations are developed to describe the displacement processes occurring before and after breakthrough. A quadratic function is introduced to represent the saturation distribution along the cores. The relationships derived in this study can be used for analysis of core tests involving constant injection rates and constant pressure differences. The applicability, practicality, and accuracy of the new analytical method are verified by means of the experimental data obtained in the present study and by those reported in the literature. 相似文献
64.
Aytaç Gültekin Gamze Karanfil Faruk Özel Mahmut Kuş Ridvan Say Savaş Sönmezoğlu 《Journal of Physics and Chemistry of Solids》2014
In the present study, pure and gold nanoparticle (Au NP)-doped titanium dioxide (TiO2) and cadmium oxide (CdO) thin film were prepared by the sol–gel method, and the effect of Au NP doping on the optical, structural and morphological properties of these thin films was investigated. The prepared thin films were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM) and ultraviolet–visible–near infrared (UV–Vis–NIR) spectra. While the optical band increases from 3.62 to 3.73 for TiO2 thin films, it decreases from 2.20 to 1.55 for CdO thin films with increasing Au doping concentration. Analysis of XRD indicates that the intensities of peaks of the crystalline phase have increased with the increasing Au NP concentrations in all thin films. SEM images demonstrate that the surface morphologies of the samples were affected by the incorporation of Au NPs. Consequently, the most significant results of the present study are that the Au NPs can be used to modify the optical, structural and morphological properties of TiO2 and CdO thin films. 相似文献
65.
66.
Zehra Olcer Mehmet Murat Ozmen Zeynep M. Sahin Faruk Yilmaz Aziz Tanriseven 《Applied biochemistry and biotechnology》2013,171(8):2142-2152
A novel method was developed for the immobilization of Saccharomyces cerevisiae invertase within supermacroporous polyacrylamide cryogel and was used to produce invert sugar. First, the cross-linking of invertase with soluble polyglutaraldehyde (PGA) was carried out prior to immobilization in order to increase the bulkiness of invertase and thus preventing the leakage of the cross-linked enzyme after immobilization by entrapment. And then, in situ immobilization of PGA cross-linked invertase within cryogel synthesis was achieved by free radical polymerization in semi-frozen state. The method resulted in 100 % immobilization and 74 % activity yields. The immobilized invertase retained all the initial activity for 30 days and 30 batch reactions. Immobilization had no effect on optimum temperature and it was 60 °C for both free and immobilized enzyme. However, optimum pH was affected upon immobilization. Optimum pH values for free and immobilized enzyme were 4.5 and 5.0, respectively. The immobilized enzyme was more stable than the free enzyme at high pH and temperatures. The kinetic parameters for free and immobilized invertase were also determined. The newly developed method is simple yet effective and could be used for the immobilization of some other enzymes and microorganisms. 相似文献
67.
K. Taymaz V. Yigit H. Özbal A. Ceritoglu N. Müftügil 《International journal of environmental analytical chemistry》2013,93(4):253-265
Abstract Mercury, cadmium and lead levels in water, sediment and fish samples from Izmit Bay, Turkey have been determined. Sampling and analysis methods are described. Variations of heavy metal concentrations from different sampling stations are discussed. Results indicate that the levels of mercury and cadmium were highest in the vicinity of a chlor-alkali plant while the highest concentration of lead was near a metallic pipe factory. The amounts of heavy metals found in the shoreline sediment samples were similar to those found in fish species from the bay. 相似文献
68.
Nano-hydroxyapatite (nHA)-matrix coatings containing graphene nanosheets (GNS)-nHA were coated on Ti6Al7Nb alloys by plasma electrolytic oxidation (PEO) treatment for the improvement of their surface properties. Crystallographic properties, functional groups, and elemental analysis of coatings were characterized by XRD, ATR–FTIR, and EDS analysis. Surface morphological changes of the coated surfaces were investigated by AFM and SEM. The electrochemical corrosion behavior of the coatings was examined by using the potentiodynamic scanning (PDS) tests under in-vitro conditions in simulated body fluid (SBF). The results showed that the GNS was successfully deposited in ceramic matrix coatings on Ti6Al7Nb alloys. Also, the microstructural observations revealed that the coatings have a porous and rough structure. The XRD and ATR–FTIR quantitative analysis have proved the appearance of HA and GNS in the coating layers. An increase in the coating thickness, surface hardness, and anatase/rutile transformation rate was determined, while the GNS ratio in the coating layers was increased. The microhardness of the nHA coating reinforced with 1.5 wt% GNS was measured at 862 HV, which was significantly higher than that of GNS-free (only nHA) coating (584 HV). The best in-vitro resistance to corrosion in SBF was observed in the nHA/1.5GNS wt% coating. 相似文献
69.
We define an analogue of the Baernstein star function for a meromorphic function f in several complex variables. This function is subharmonic on the upper half-plane and encodes some of the main functionals attached to f. We then characterize meromorphic functions admitting a harmonic star function. 相似文献
70.
We define and investigateCD
Σ,Γ(K, E)-type spaces, which generalizeCD
0-type Banach lattices introduced in [1]. We state that the space CD
Σ,Γ(K, E) can be represented as the space of E-valued continuous functions on the generalized Alexandroff Duplicate of K. As a corollary we obtain the main result of [6, 8]. 相似文献