全文获取类型
收费全文 | 1084篇 |
免费 | 55篇 |
国内免费 | 44篇 |
专业分类
化学 | 566篇 |
晶体学 | 18篇 |
力学 | 34篇 |
综合类 | 12篇 |
数学 | 149篇 |
物理学 | 404篇 |
出版年
2022年 | 8篇 |
2020年 | 10篇 |
2019年 | 17篇 |
2018年 | 14篇 |
2017年 | 22篇 |
2016年 | 14篇 |
2015年 | 20篇 |
2014年 | 30篇 |
2013年 | 69篇 |
2012年 | 37篇 |
2011年 | 51篇 |
2010年 | 20篇 |
2009年 | 31篇 |
2008年 | 49篇 |
2007年 | 49篇 |
2006年 | 50篇 |
2005年 | 57篇 |
2004年 | 37篇 |
2003年 | 31篇 |
2002年 | 31篇 |
2001年 | 31篇 |
2000年 | 30篇 |
1999年 | 15篇 |
1998年 | 9篇 |
1997年 | 13篇 |
1996年 | 23篇 |
1995年 | 15篇 |
1994年 | 13篇 |
1993年 | 20篇 |
1992年 | 15篇 |
1991年 | 17篇 |
1990年 | 17篇 |
1989年 | 24篇 |
1988年 | 15篇 |
1987年 | 19篇 |
1985年 | 28篇 |
1984年 | 19篇 |
1983年 | 8篇 |
1982年 | 15篇 |
1981年 | 13篇 |
1980年 | 22篇 |
1978年 | 18篇 |
1977年 | 15篇 |
1976年 | 14篇 |
1975年 | 12篇 |
1974年 | 10篇 |
1973年 | 7篇 |
1972年 | 8篇 |
1971年 | 8篇 |
1969年 | 8篇 |
排序方式: 共有1183条查询结果,搜索用时 15 毫秒
51.
52.
LIU Yan-Ping CHEN Zhao-Yang BA Wei-Zhen FAN Yan-Wei DU Yan-Zhao PAN Shi-Lie GUO Qi 《中国物理C(英文版)》2008,32(5)
The optically stimulated luminescent (OSL) radiation dosimeter technically surveys a wide dynamic measurement range and a high sensitivity.Optical fiber dosimeters provide capability for remote monitoring of the radiation in the locations which are difficult-to-acoess and hazardous.In addition.optical fiber dosimeters are immune to electrical and radio-frequency interference.In this paper,a novel remote optical fiber radiation dosimeter is described.The optical fiber dosimeter takes advantage of the charge trapping materials CaS:Ce, Sm that exhibit OSL.The measuring range of the dosimeter is from 0.1 to 100 Gy.The equipment is relatively simple and small in size,and has low power consumption.This device is suitable for measuring the space radiation dose and also can be used in high radiation dose condition and other dangerous radiation occasions. 相似文献
53.
Charles E. Carraher Jr. George F. Peterson John E. Sheats Ted Kirsch 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(6):1009-1022
The synthesis of oligomeric tin poly(cobalticinium esters) is presented as a function of the particular reaction variables stirring rate, pH and amount of added base, mole ratio of reactants, concentration of reactants, and volume of organic phase. Factors which decrease the solubility of the stannane apparently act to increase the yield of polyester. The thermal characterization of I was carried out via DSC and TGA. The products generally exhibit endotherms below 150 to 200[ddot]C which may be related to Tg. Above 200[ddot]C, degradation occurs in air by an oxidative mode. 相似文献
54.
Abstract An analysis is presented to show that a miniature wet-bulb/dry-bulb probe can provide easy, rapid, and accurate point measurements of noncondensable gas concentrations in condensing or evaporating systems. The probe consists of a liquid-soaked porous sphere as small as 0.5 mm in diameter with a fine-gauge thermocouple embedded at its center. Performance of the probe is shown to improve with decreasing wet-bulb size. Measurements of only the total pressure and point wet-bulb temperature are needed to determine the local gas concentration for most gas-vapor systems. The use of the technique in systems with steep concentration gradients is demonstrated by application to the well-studied problem of the gas-loaded two-phase thermosyphon. 195pt 相似文献
55.
56.
57.
58.
59.
2-Bromo-6-lithiopyridine adds stereoselectively to the β-face of 1,2;5,6-di-O-isopropylidene-α-D-glucofuranos-3-ulose (2) to provide compound 5 in 50% yield as a single diastereomer. Compound 5 can be coupled to form novel C2-symmetric 2,2′-bipyridine 7, the first example of a C2-symmetric bipyridine that derives chirality from glucose. 相似文献
60.
Methyl acetoacetate and 2,4-pentanedione dianions were condensed with aldehydes and ketones to afford a 1,3,5-trioxygenated carboskeleton. Intramolecular cyclization of the aldol adducts delivered the title compounds in good yield. 相似文献