全文获取类型
收费全文 | 1663379篇 |
免费 | 37491篇 |
国内免费 | 10598篇 |
专业分类
化学 | 755590篇 |
晶体学 | 20931篇 |
力学 | 77189篇 |
综合类 | 168篇 |
数学 | 254971篇 |
物理学 | 396830篇 |
无线电 | 205789篇 |
出版年
2021年 | 15396篇 |
2020年 | 19051篇 |
2019年 | 20124篇 |
2018年 | 17206篇 |
2017年 | 15557篇 |
2016年 | 33392篇 |
2015年 | 24484篇 |
2014年 | 35453篇 |
2013年 | 82750篇 |
2012年 | 48388篇 |
2011年 | 49285篇 |
2010年 | 45669篇 |
2009年 | 49694篇 |
2008年 | 51210篇 |
2007年 | 48645篇 |
2006年 | 51891篇 |
2005年 | 45507篇 |
2004年 | 44638篇 |
2003年 | 41052篇 |
2002年 | 41528篇 |
2001年 | 41008篇 |
2000年 | 35463篇 |
1999年 | 30717篇 |
1998年 | 28204篇 |
1997年 | 27936篇 |
1996年 | 27472篇 |
1995年 | 25114篇 |
1994年 | 24676篇 |
1993年 | 24118篇 |
1992年 | 24316篇 |
1991年 | 24301篇 |
1990年 | 23085篇 |
1989年 | 22628篇 |
1988年 | 21813篇 |
1987年 | 20495篇 |
1986年 | 19398篇 |
1985年 | 25838篇 |
1984年 | 26819篇 |
1983年 | 22599篇 |
1982年 | 23953篇 |
1981年 | 23089篇 |
1980年 | 22369篇 |
1979年 | 22418篇 |
1978年 | 23562篇 |
1977年 | 23143篇 |
1976年 | 22803篇 |
1975年 | 21453篇 |
1974年 | 21113篇 |
1973年 | 21563篇 |
1972年 | 15746篇 |
排序方式: 共有10000条查询结果,搜索用时 812 毫秒
51.
Yuki Shintani Taku Ohtomi Dr. Aya Shibata Dr. Yoshiaki Kitamura Koichiro M. Hirosawa Prof. Kenichi G. N. Suzuki Prof. Masato Ikeda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(8):e202104421
Aqueous self-assembly of short peptides has attracted growing attention for the construction of supramolecular materials for various bioapplications. Herein, we describe how the thermolysin-assisted biocatalytic construction of a dipeptide hydrazide from an N-protected amino acid and an amino acid hydrazide leads to the formation of thermally stable supramolecular hydrogels. In addition, we demonstrate the post-assembly modification of the supramolecular architectures constructed in situ tethering hydrazide groups as a chemical handle by means of fluorescence imaging. 相似文献
52.
Journal of Structural Chemistry - Atomic and electronic structures of cyclic organosilicon compound 9,9,10,10-tetraethynyl-9,10-dihydrodisilaanthracene are studied by the density functional theory.... 相似文献
53.
Photoresponsive biomaterials are experiencing a transition from in vitro models to in vivo demonstrations that point toward clinical translation. Dynamic hydrogels for cell encapsulation, light-responsive carriers for controlled drug delivery, and nanomaterials containing photosensitizers for photodynamic therapy are relevant examples. Nonetheless, the step to the clinic largely depends on their combination with technologies to bring light into the body. This review highlights the challenge of photoactivation in vivo, and presents strategies for light management that can be adopted for this purpose. The authors’ focus is on technologies that are materials-driven, particularly upconversion nanoparticles that assist in “direct path” light delivery through tissue, and optical waveguides that “clear the path” between external light source and in vivo target. The authors’ intention is to assist the photoresponsive biomaterials community transition toward medical technologies by presenting light delivery concepts that can be integrated with the photoresponsive targets. The authors also aim to stimulate further innovation in materials-based light delivery platforms by highlighting needs and opportunities for in vivo photoactivation of biomaterials. 相似文献
54.
Journal of Experimental and Theoretical Physics - The surface current density of charge carriers in two-dimensional doubly periodic n-type semiconductor superlattices in an external magnetic field... 相似文献
55.
Tsyganova S. I. Fetisova O. Yu. Mazurova E. N. Taran O. P. Kuznetsov B. N. 《Russian Journal of Applied Chemistry》2022,95(3):408-416
Russian Journal of Applied Chemistry - A method for the disposal of hydrolysis lignin waste based on its modification with ZnCl2 and FeCl3 and subsequent carbonization at 800°C was proposed.... 相似文献
56.
Roopa K. P. Keshavamurthy K. Mahesh B. Veena K. P. Shankara B. S. Basavaiah K. 《Journal of Applied Spectroscopy》2022,89(4):809-818
Journal of Applied Spectroscopy - Three simple, sensitive, precise, and rapid spectrophotometric methods are developed and optimized for the assay of vardenafil in pharmaceutical formulations. The... 相似文献
57.
Russian Journal of Applied Chemistry - In September 1975, the head of Russian electrochemists, Academician A.N. Frumkin (1895–1976), in his report at the XI Mendeleev Congress on General and... 相似文献
58.
Theoretical and Mathematical Physics - We study a phenomenological model in which dark matter in the cosmological constant form is identified with the mean energy–momentum tensor of a... 相似文献
59.
Moroz Ya. A. Lozinskyy N. S. Lopanov A. N. Chebyshev K. A. 《Russian Journal of General Chemistry》2022,92(1):101-107
Russian Journal of General Chemistry - Tungstophosphatozincates with the Keggin anion structure Kt5[PW11O39Zn(H2O)]?nH2O, Kt = Rb+, Cs+, (CH3)4N+; (C2H5)4N+ were synthesized. Their... 相似文献
60.
Filatova S. M. Guseva M. K. Bodrova T. G. Parshina D. V. Budanova U. A. Sebyakin Yu. L. 《Russian Journal of General Chemistry》2022,91(1):S13-S23
Russian Journal of General Chemistry - The review article traces the main trends of the synthetic approach to the solution of the problem of overcoming the resistance of pathogenic bacterial... 相似文献