全文获取类型
收费全文 | 2642篇 |
免费 | 77篇 |
国内免费 | 21篇 |
专业分类
化学 | 2151篇 |
晶体学 | 21篇 |
力学 | 16篇 |
数学 | 159篇 |
物理学 | 393篇 |
出版年
2023年 | 18篇 |
2022年 | 19篇 |
2021年 | 29篇 |
2020年 | 35篇 |
2019年 | 53篇 |
2018年 | 31篇 |
2017年 | 29篇 |
2016年 | 60篇 |
2015年 | 70篇 |
2014年 | 66篇 |
2013年 | 130篇 |
2012年 | 177篇 |
2011年 | 205篇 |
2010年 | 121篇 |
2009年 | 108篇 |
2008年 | 192篇 |
2007年 | 180篇 |
2006年 | 136篇 |
2005年 | 159篇 |
2004年 | 152篇 |
2003年 | 118篇 |
2002年 | 128篇 |
2001年 | 33篇 |
2000年 | 43篇 |
1999年 | 30篇 |
1998年 | 33篇 |
1997年 | 23篇 |
1996年 | 28篇 |
1995年 | 30篇 |
1994年 | 25篇 |
1993年 | 25篇 |
1992年 | 20篇 |
1991年 | 23篇 |
1990年 | 15篇 |
1989年 | 18篇 |
1988年 | 15篇 |
1987年 | 11篇 |
1986年 | 23篇 |
1985年 | 28篇 |
1984年 | 24篇 |
1983年 | 8篇 |
1982年 | 12篇 |
1981年 | 10篇 |
1980年 | 7篇 |
1979年 | 6篇 |
1978年 | 7篇 |
1975年 | 6篇 |
1973年 | 3篇 |
1972年 | 5篇 |
1970年 | 3篇 |
排序方式: 共有2740条查询结果,搜索用时 15 毫秒
891.
Dr. Minh Anh Truong Dr. Jaehyun Lee Tomoya Nakamura Dr. Ji-Youn Seo Mina Jung Masashi Ozaki Ai Shimazaki Dr. Nobutaka Shioya Prof. Dr. Takeshi Hasegawa Prof. Dr. Yasujiro Murata Dr. Shaik Mohammed Zakeeruddin Prof. Dr. Michael Grätzel Dr. Richard Murdey Prof. Dr. Atsushi Wakamiya 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(27):6741-6752
A series of two-dimensionally expanded azulene-core-based π systems have been synthesized with different alkyl chain lengths in the alkoxy moieties connected to the partially oxygen-bridged triarylamine skeletons. The thermal, photophysical, and electronic properties of each compound were evaluated to determine the influence of the alkyl chain length on their effectiveness as hole-transporting materials (HTMs) in perovskite solar cells (PSCs). All the synthesized molecules showed promising material properties, including high solubility, the formation of flat and amorphous films, and optimal alignment of energy levels with perovskites. In particular, the derivatives with methyl and n-butyl in the side chains retained amorphous stability up to 233 and 159 °C, respectively. Such short alkoxy chains also resulted in improved electrical device properties. The PSC device fabricated with the HTM with n-butyl side chains showed the best performance with a power conversion efficiency of 18.9 %, which compares favorably with that of spiro-OMeTAD-based PSCs (spiro-OMeTAD=2,2′,7,7′-tetrakis[N,N-bis(p-methoxyphenyl)amino]-9,9′-spirobifluorene). 相似文献
892.
Dr. Masaki Yoshida Hotaka Shitama Dr. W. M. C. Sameera Dr. Atsushi Kobayashi Prof. Dr. Masako Kato 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(32):7669-7678
An electrochromic system showing ease of color tunability has been constructed using a triple-decker PtII complex [Pt3(μ3-pydt)2(bpy)3]2+ (H2pydt=2,6-pyridinedithiol, bpy=2,2′-bipyridine). The divalent complex undergoes electrochemically quasi-reversible two-electron transfer coupled with the coordination/dissociation of axial ligands, forming higher valent Pt(+2.67) species [Pt3X2(μ3-pydt)2(bpy)3]2+ (X=Cl−, Br−, and SCN−). These higher valent species exhibit characteristic colors ranging from red to cyan depending on the counter anion X− of the electrolyte. The triple-decker structure provides a novel multicolor electrochromic system with favorable stability and reversibility. Theoretical calculations indicate that the colors of the Pt(+2.67) species are tunable by the trans influence of the axial ligand X−. This novel strategy of post-synthetic color-tuning using triplatinum systems should enable the facile preparation of colorful electrochromic devices without any complicated procedures, which may find application in flexible displays, optical devices, and sensors. 相似文献
893.
Takashi Doi Tsutomu Shimokawa Atsushi Sudo Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》2019,57(4):531-538
This article presents the effect of some ionic photochemical acid generators (PAGs) to inhibit the dissolution of hexafluoroisopropylalcohol (HFA)‐containing polystyrene to an aqueous alkaline developer, which is a highly important effect in photoresist application to enhance resolution of patterning. The dissolution inhibiting factors and mechanisms were investigated by evaluating the solubility and the 1H‐NMR analysis of OH proton in HFA moiety. The dissolution inhibition effect was enhanced when the structures of PAGs fulfill some requirements: (a) their anions should have higher basicity and smaller van der Waals volume; (b) their cations should be stabilized by conjugation with electron‐rich aromatics. In the dissolution inhibition, the HFA moiety interacts with the anionic part of PAGs liberated from the electrostatic interaction with the counter cation. These interactions were predicted and quantified by DFT calculations using Gaussian 09, leading to the rational designs of PAGs with higher dissolution inhibiting effect in photoresist systems. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 531–538 相似文献
894.
Yasuyuki Mori Atsushi Sudo Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》2019,57(14):1564-1568
Oligo(spiroorthocarbonate)s 1 , which were synthesized by the polycondensation of pentaerythritol derivatives with tetraethylorthocarbonate, were employed as comonomers in the cationic polymerization of epoxide initiated by sulfonium salt. In the copolymerization, the spiroorthocarbonate moiety of 1 underwent double ring‐opening reaction, leading to the efficient diminution of the volume shrinkage upon the copolymerization. Thermal properties of the resulting networked polymers were evaluated by TGA. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1564–1568 相似文献
895.
896.
Drying dissipative structures of the aqueous suspensions of palygorskite and tungstic acid particles
Macroscopic and microscopic dissipative structural patterns during dryness of the aqueous suspensions of palygorskite (PGK,
needle-like shaped) and tungstic acid (TA, plate-like) have been studied on a cover glass. The coexistence of the broad ring
of the hill accumulated with the particles and the round hills is observed around the outside edges of the dried film and
in the center, respectively. These patterns differ from those of the suspensions of spherical particles. Furthermore, the
spoke-like patterns, which have been observed for the suspensions of the spherical particles so often, are not observed at
all for PGK and TA suspensions. These characteristic macroscopic patterns of PGK and TA are quite similar to those of the
fractionated and monodispersed bentonites (plate-like) reported previously Yamaguchi et al. (Colloid Polymer Sci 283:1123,
2005). Wrinkled and/or branch-like fractal patterns are observed in the microscopic scale, which are quite similar to those of
bentonites. “Shape information” of the colloidal particles is clarified to be “transferred” to the drying patterns via the
convectional and sedimentary patterns during the course of dryness. 相似文献
897.
Takashi Yamazaki Tomoko Kawasaki-Takasuka Atsushi Furuta Shogo Sakamoto 《Tetrahedron》2009,65(31):5945-1960
Smooth isomerization of 4,4,4-trifluorinated propargylic alcohols 1 opened a new and convenient route to readily get access to the corresponding α,β-unsaturated ketones 4 just by heating a THF solution in the presence of Et3N. 相似文献
898.
899.
900.