全文获取类型
收费全文 | 10275篇 |
免费 | 793篇 |
国内免费 | 2552篇 |
专业分类
化学 | 6806篇 |
晶体学 | 81篇 |
力学 | 667篇 |
综合类 | 100篇 |
数学 | 1570篇 |
物理学 | 4396篇 |
出版年
2024年 | 4篇 |
2023年 | 28篇 |
2022年 | 69篇 |
2021年 | 77篇 |
2020年 | 105篇 |
2019年 | 76篇 |
2018年 | 68篇 |
2017年 | 93篇 |
2016年 | 107篇 |
2015年 | 151篇 |
2014年 | 166篇 |
2013年 | 284篇 |
2012年 | 286篇 |
2011年 | 1502篇 |
2010年 | 830篇 |
2009年 | 886篇 |
2008年 | 327篇 |
2007年 | 323篇 |
2006年 | 378篇 |
2005年 | 585篇 |
2004年 | 1397篇 |
2003年 | 835篇 |
2002年 | 740篇 |
2001年 | 642篇 |
2000年 | 281篇 |
1999年 | 278篇 |
1998年 | 302篇 |
1997年 | 205篇 |
1996年 | 147篇 |
1995年 | 142篇 |
1994年 | 121篇 |
1993年 | 454篇 |
1992年 | 507篇 |
1991年 | 323篇 |
1990年 | 323篇 |
1989年 | 318篇 |
1988年 | 83篇 |
1987年 | 21篇 |
1986年 | 34篇 |
1985年 | 28篇 |
1984年 | 20篇 |
1983年 | 15篇 |
1982年 | 13篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1977年 | 3篇 |
1938年 | 4篇 |
1918年 | 2篇 |
1911年 | 2篇 |
1893年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 250 毫秒
301.
蒸馏沉淀聚合过程中交联度对单分散聚合物微球形成的影响书 总被引:2,自引:0,他引:2
以苯乙烯为单体、二乙烯基苯(DVB)为交联剂,过氧化二苯甲酰(BPO)为引发剂研究了蒸馏沉淀聚合法制备聚合物微球过程中交联单体二乙烯苯的用量对单分散聚合物微球成球的影响。结果表明,增加二乙烯基苯的比例,即提高交联度有利于形成单分散的聚合物微球。 相似文献
302.
303.
Wei Shuo FANG* Ying LIU Qi Cheng FANG Institute of Materia Medica Chinese Academy of Medical Sciences Peking Union Medical College Beijing 《中国化学快报》2002,(8)
The chemistry of anticancer drug paclitaxel (=Taxol, 1a) has been extensively explored in recent years. A variety of its analogs with modified taxane frame work or substitutions to its core structure, as well as C-13 substituted isoserine side chains have been synthesized and biologically evaluated1. The marketing of docetaxel (=Taxotere, 1b) is one of the fruitful results from these research efforts. The beginning of clinical trial for analog 2 developed by Indena is the new example. Ba… 相似文献
304.
MinHAO DaXING QunCHEN JuanWANG 《中国化学快报》2004,15(6):679-682
This paper, for the first time, reports a method that can be used as a highly sensitive probe for singlet oxygen (^1O2) and superoxide anion (O2^-) in vitro or in vivo. FCLA(3,7-dihydro-6-{4-[2-(N‘-(5-fluoresceinyl)thioureido)ethoxy]phenyl}-2-methylimidazo{1,2-a}pyrazin-3-one sodium salt), a chemiluminescence (CL) analysis reagent, has been reported to sensitively react with ^1O2 and O2^- to emit photons with a spectral peak of 525nm. In this work,when human serum albumin (HSA) was added into FCLA solution to enhance the CL intensity,approximately 20 times, compared to that without HSA. The enhanced CL had the same 525 nm spectral peak, identical to that without HSA. By gradually reducing the molecular oxygen content in the solution, we find that the auto-oxidation of oxygen molecules dissolved in the solution plays an important role in the CL process. Based on these experimental evidences, we propose a novel and highly sensitive detection method of ^1O2 and O2^- which may have a great potential in chemical and medical applications. 相似文献
305.
MingZhuLIU ShengYiZHANG YuHuaSHEN MingLiangZHANG 《中国化学快报》2004,15(10):1249-1252
Selenium nanoparticles were prepared by a reverse microemulsion system. Sodium selenosulfate was used as selenium source. The results showed that hydrochloric acid concentration and reaction temperature had great influence on the morphology of products. The crystalline selenium nanowires and amorphous selenium nanorods were obtained in given condition. 相似文献
306.
醇盐法制备稀土化合物超微粉末 总被引:16,自引:2,他引:16
稀土元素具有广泛的用途,在大多数的应用中其效果都与原料的纯度、粒度、粒经分布范围等因素有关。由于超微粉末的比表面积大、化学活性高,因此可以预料,若将稀土化合物制成超微粉末,会使它的催化性能及在各种材料中的性能有明显的改变,也可使稀土有新的、更高的应用价值。 相似文献
307.
308.
XU Zhi-Jin YAN Ji-MinInstitute of Chemistry Chinese Academy of Sciences Beijing China 《中国化学》1996,14(6):481-489
The interaction between C60's in solid C60 has been calculated by (exp-6-1) potential, and the cause and the controlled factor of the high rapid rotations of C60 's were discussed. In order to describe the disordered degree of C60 rotation, an equivalent M is introduced. The phase transitions at the ~260 K and at the ~90 K are studied from the viewpoint of C60 rotation. The potential barriers of the ordered rotation below the ~260 K and the disordered rotation above the ~260 K have been given, and the effect of the external pressure on the temperature of phase transition has also been given. 相似文献
309.
310.
Density of supercritical CO_2-tetrahydrofuran binary mixture and the partial molar volume of the cosolvent 总被引:1,自引:0,他引:1
The densities of supercritical CO2-tetrahydrofuran (cosolvent) binary mixture weremeasured at temperatures in range of 308.15 to 323.15 K and at pressure up to 16.5 MPa.The concentrations of tetrahydrofuran were from 0 to 0.57 mol/L.The partial molar volume of tetrahydrofuran was calculated based on the relationship between the density of the mixture and the concentration of the cosolvent.It is observed that the partial molar volume of the cosolvent is negative and the absolute value decreases with increasing pressure and the concentration of the cosolvent. 相似文献