全文获取类型
收费全文 | 19639篇 |
免费 | 3672篇 |
国内免费 | 2935篇 |
专业分类
化学 | 14226篇 |
晶体学 | 330篇 |
力学 | 1193篇 |
综合类 | 203篇 |
数学 | 2451篇 |
物理学 | 7843篇 |
出版年
2024年 | 50篇 |
2023年 | 387篇 |
2022年 | 613篇 |
2021年 | 695篇 |
2020年 | 864篇 |
2019年 | 835篇 |
2018年 | 732篇 |
2017年 | 709篇 |
2016年 | 1054篇 |
2015年 | 1034篇 |
2014年 | 1275篇 |
2013年 | 1522篇 |
2012年 | 1960篇 |
2011年 | 1964篇 |
2010年 | 1395篇 |
2009年 | 1325篇 |
2008年 | 1478篇 |
2007年 | 1208篇 |
2006年 | 1084篇 |
2005年 | 939篇 |
2004年 | 762篇 |
2003年 | 582篇 |
2002年 | 567篇 |
2001年 | 473篇 |
2000年 | 364篇 |
1999年 | 391篇 |
1998年 | 265篇 |
1997年 | 211篇 |
1996年 | 223篇 |
1995年 | 199篇 |
1994年 | 186篇 |
1993年 | 121篇 |
1992年 | 124篇 |
1991年 | 116篇 |
1990年 | 125篇 |
1989年 | 83篇 |
1988年 | 58篇 |
1987年 | 39篇 |
1986年 | 50篇 |
1985年 | 39篇 |
1984年 | 34篇 |
1983年 | 29篇 |
1982年 | 19篇 |
1981年 | 18篇 |
1979年 | 5篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1974年 | 6篇 |
1973年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
1.INTRODUCTION[()-227.3()]Endotoxinislipopolysaccharide(LPS)derivedfromthecellmembranesofgram-negativebacteria.Endotoxincancausefebrilereactionsinanimalswithsymptomsofhighfever,vasodilation,diarrheaandfetalshockwheninjectedeveninaverysmallamount[1].Iftheconcentrationofendotoxininpatients?bloodishighenoughitcancauseseveresepsis,whichisamajorcauseofdeathinpatientsandcontinuestohaveahighmortalitydespiteappropriatesurgery,potentantibiotic,andintensivesupportivetherapy[2~5].LipidAisthemaintox… 相似文献
52.
Ching Sum Hui Lillian Sze Man Lam Chun Yin Wai Kin Chan Aleksandra B. Djurii 《Journal of polymer science. Part A, Polymer chemistry》2003,41(11):1708-1715
Polyurethanes incorporated with rhenium diimine complexes were synthesized. The polymers exhibited interesting morphologies and solution properties. Results from gel permeation chromatography suggested the formation of polymer aggregates in solutions. The polymers could act as probes for metal ions. The addition of metal ions to polymer solutions led to significant changes in the electronic absorption properties of the polymer solutions. This was attributed to the interactions between the polyether moieties and metal ions. The metal complexes could also act as efficient photosensitizers. After doping with charge‐transport viologens, the photoconductivity of the polymers was greatly enhanced. The experimental quantum efficiency was simulated with Onsager's theory. The thermalization distances and the primary yields were typically 12–14 Å and 10?3, respectively. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1708–1715, 2003 相似文献
53.
54.
55.
Kosuke Morita Kouji Morimoto Daiya Kaji Yu Liang Zhao Atsushi Yoshida Toshimi Suda Akira Yoneda Tetsuya Ohnishi Hiromitsu Haba Eiji Ideguchi Hu Shan Xu Tao Zheng Hisaaki Kudo Keisuke Sueki Kenji Katori Isao Tanihata 《Acta Physica Hungarica A》2004,19(1-2):53-60
A gas-filled type of recoil separator for heavy element research was installed at an experimental hall of RIKEN Linear Accelerator facility to realize getting higher intensity of primary beam and long beam time. Performance of the separator was studied using target recoils and various nuclear reactions. The results show the high performance of the separator for heave element research. As an application of the GARIS, production and identification of an isotope of the 110th element 271[110] have been performed using the 208Pb(64Ni,1n)271[110] reaction. Three decay chains coincide well both in decay times and energies with the ones reported by the group of SHIP experiment at GSI, Germany. Our results provide a confirmation of the synthesis of an isotope 271[110] of element 110. 相似文献
56.
57.
A New Triterpene from the Orchid Pholidota yunnanensis 总被引:2,自引:0,他引:2
ZhiMingBI ZhengTaoWANG LuoShanXU 《中国化学快报》2004,15(10):1179-1181
A new triterpene, 25-methylenecyclopholidonyl p-hydroxy-trans-cinnamate, was isolated from a orchid Pholidota yunnanensis. The structure elucidation and ^1H, ^13C-NMR assignments were achieved by spectral and chemical method. 相似文献
58.
Qing An WU Zhen Yuan XU Mei ZHENG Dan Qian XU Jun XU Yin Chu SHENCollege of Chemical Engineering Materials Zhejiang University of Technology Hangzhou 《中国化学快报》2004,(7)
Six new 13-O-acylavermectin Bl aglycones(3-8) were synthesized from avermectin B1 aglycone and their bioactivities were evaluated against Spodoptera exigua, Spodoptera eridania, Tetranychus urticae and Aphis fabae. 相似文献
59.
Zhaoyang Yin 《Monatshefte für Mathematik》2004,141(4):337-344
We prove under quite general assumptions the existence of a bounded positive solution to the semilinear Schrödinger equation in a two-dimensional exterior domain. 相似文献
60.