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991.
992.
993.
Rigid diol bearing 6‐6‐6 fused ring system derived from naturally occurring myo‐inositol and its polyaddition with diisocyanates
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Arata Yoshida Atsushi Sudo 《Journal of polymer science. Part A, Polymer chemistry》2017,55(22):3798-3803
Naturally occurring myo‐inositol was developed into a highly rigid diol by converting its 3,4‐ and 1,6‐vicinal diols in trans configuration into the corresponding butane‐2,3‐diacetals. The resulting diol bearing 6‐6‐6 fused ring system, in which conformational change is strictly suppressed, was combined with diisocyanates to perform polyadditions. The resulting polyurethanes were analyzed by differential scanning calorimetry, and it was found that their glass transition temperatures were much higher than those of the previously reported myo‐inositol‐derived polyurethanes, which were synthesized from a myo‐inositol‐derived diol bearing 5‐6‐5 fused ring system. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3798–3803 相似文献
994.
995.
Ozao R. Yoshida H. Ichimura Y. Inada T. Ochiai M. 《Journal of Thermal Analysis and Calorimetry》2001,64(3):915-922
The thermal change of anodic alumina (AA), particularly the exothermic peak followed by the endothermic peak at ca 950°C was
studied in detail by mainly using simultaneous TG-DTA/FTIR. The gradual loss of mass up to ca 910°C is attributed to dehydration.
When heated at a constant rate by using TG-DTA, an exothermic peak with subsequent endothermic peak is observed at ca 950°C,
but the exothermic peak becomes less distinct with decreasing heating rate. It has been found that gaseous SO2 accompanying a small amount of CO2 is mainly discharged at this stage. The reaction in this stage can be considered roughly in two schemes. The first scheme
can be said collectively as crystallization, in which the migration of S or C trapped inside the crystal lattice of the polycrystalline
phase (γ-, δ-, and θ-Al2O3, which presumably accompanies a large amount of amorphous or disordered phase) occurs. In the second scheme, the initial
polycrystalline (+amorphous) phase crystallizes into a quasi-crystallineγ-Al2O3-like metastable phase after amorphization. Conclusively,after the distinct exo- and endothermic reactions, the amorphous
phase crystallizes intoγ-Al2O3, presumably accompanying small amount of δ-Al2O3. It is also found that, when maintained isothermally, the metastable phases undergo transformation into the stable α-Al2O3 at 912°C.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
996.
Inside Back Cover: Electrical Network of Single‐Crystalline Metal Oxide Nanoclusters Wired by π‐Molecules (Angew. Chem. Int. Ed. 42/2014)
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997.
Ranko Motoshige Yasuteru Mawatari Asahi Motoshige Yoshiaki Yoshida Takahiro Sasaki Hiroaki Yoshimizu Tomoyuki Suzuki Yoshiharu Tsujita Masayoshi Tabata 《Journal of polymer science. Part A, Polymer chemistry》2014,52(6):752-759
The yellow‐colored poly(phenylacetylene), Poly( Y ), is obtained from phenylacetylene using a [Rh(nbd)Cl]2‐NEt3 catalyst in ethanol at 25 °C. The color of Poly( Y ) drastically changes into red Poly( R ) or reddish‐black Poly( B ) by immersion in acetylacetone or exposure to chloroform vapor, respectively. Poly( R ) is also created from Poly( B ) by contact with acetylacetone. Poly( Y ) is regenerated from both Poly( R ) and Poly( B ) by reprecipitation from their chloroform solution into methanol. Wide‐angle X‐ray scattering (WAXS) patterns of Poly( Y ) and Poly( R ) correspond to a pseudohexagonal crystal called a columnar as stretched cis‐transoid and contracted cis‐cisoid helices, respectively. These helical diameters and pitch widths obtained from the WAXS measurements are agreed with those of MMFF94 calculation models. The smallest helical pitch width is 3.3 Å for Poly( R ) and Poly( B ). Moreover, information regarding the size and ordering of the vacant space within each polymer is estimated by using 129Xe NMR technique. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 752–759 相似文献
998.
Ryo Tanaka Takuya Suenaga Zhengguo Cai Yuushou Nakayama Takeshi Shiono 《Journal of polymer science. Part A, Polymer chemistry》2014,52(2):267-271
A–B–A block copolymers which consist of poly(norbornene‐co‐1‐octene) and atactic polypropylene (PP) segments were synthesized by using ansa‐fluorenylamidotitanium complex as a catalyst varying the ratio of norbornene, 1‐octene, and propylene. The copolymer was obtained quantitatively with high molecular weight (>100,000) and narrow molecular weight distribution (polydispersity index, <1.5). A–B block copolymers of poly(norbornene‐co‐1‐octene) and poly(methyl methacrylate) (PMMA) was also obtained by the same procedure. Mechanical and optical properties of these copolymer films, which were obtained by solution casting process, were also investigated. Introduction of PP soft segment greatly improved mechanical properties, keeping their high transparency. Introduction of PMMA block also increased the tensile strength. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 267–271 相似文献
999.
Ayako Nakamura Sylvain Lectard Ryo Shimizu Yoshitaka Hamashima Mikiko Sodeoka 《Tetrahedron: Asymmetry》2010,21(13-14):1682-1687
As a part of our research project on hard anion-late transition metal complexes as mild acid–base catalysts, we describe herein that CuII hydroxo complexes having chiral N-substituted-diaminocyclohexanes are mild and selective catalysts, which are applicable to the catalytic asymmetric conjugate addition of α-keto esters to nitroolefins. The reaction proceeded diastereoselectively without the detectable formation of self-aldol products, affording the corresponding coupling products with anti-stereochemistry in an enantioselective manner. 相似文献
1000.
Munenori Yoshida Gaku Nakanishi Hiromi Yamanaka Satoru Iwamori 《Surface and interface analysis : SIA》2022,54(7):759-766
Polyether ether ketone (PEEK) is a substrate for metal plating to overcome insulation defects and satisfy the increased demands of mechanically robust electronic circuit boards. However, pristine PEEK is hydrophobic; hence, the adhesion between the metal film and PEEK substrate is poor. Therefore, the PEEK surface should be modified to improve hydrophobicity. We have proposed the active oxygen (AOS) treatment under ultraviolet (UV) light as an alternative to a conventional plasma treatment method. Characteristics of the PEEK surfaces obtained by these methods are compared. We explore the effects of reactive-oxygen and UV light exposure time on the PEEK surface modification. The contact angle of water drop on PEEK after the AOS treatment is lower than that of untreated PEEK. Furthermore, COO groups are observed on the PEEK surface after the treatment. Although plasma treatment has the effect of roughening the surface, it is desirable not to roughen the surface for use in electronic circuit boards. Moreover, we have reported the adhesion strength between PEEK and copper plating without surface roughening. 相似文献