全文获取类型
收费全文 | 7100篇 |
免费 | 1309篇 |
国内免费 | 660篇 |
专业分类
化学 | 5245篇 |
晶体学 | 70篇 |
力学 | 189篇 |
综合类 | 70篇 |
数学 | 941篇 |
物理学 | 2554篇 |
出版年
2024年 | 9篇 |
2023年 | 62篇 |
2022年 | 169篇 |
2021年 | 180篇 |
2020年 | 286篇 |
2019年 | 200篇 |
2018年 | 236篇 |
2017年 | 241篇 |
2016年 | 400篇 |
2015年 | 355篇 |
2014年 | 508篇 |
2013年 | 622篇 |
2012年 | 451篇 |
2011年 | 482篇 |
2010年 | 383篇 |
2009年 | 454篇 |
2008年 | 451篇 |
2007年 | 486篇 |
2006年 | 447篇 |
2005年 | 384篇 |
2004年 | 368篇 |
2003年 | 324篇 |
2002年 | 220篇 |
2001年 | 191篇 |
2000年 | 149篇 |
1999年 | 164篇 |
1998年 | 111篇 |
1997年 | 129篇 |
1996年 | 91篇 |
1995年 | 86篇 |
1994年 | 65篇 |
1993年 | 40篇 |
1992年 | 38篇 |
1991年 | 41篇 |
1990年 | 22篇 |
1989年 | 23篇 |
1988年 | 38篇 |
1987年 | 30篇 |
1986年 | 14篇 |
1985年 | 16篇 |
1984年 | 28篇 |
1983年 | 5篇 |
1982年 | 12篇 |
1981年 | 9篇 |
1980年 | 14篇 |
1979年 | 12篇 |
1978年 | 7篇 |
1977年 | 8篇 |
1976年 | 4篇 |
1973年 | 3篇 |
排序方式: 共有9069条查询结果,搜索用时 46 毫秒
91.
92.
因子分析—伏安法同时测定波峰重叠的混合物组份 总被引:3,自引:1,他引:3
本文将目标因子分析用于伏安分析法同时测定波峰重叠的混合物组份。用此法对Pb(Ⅱ)、Tl(I)混合体系的导数脉冲伏安重叠峰数据进行解析,获得了较理想的结果。 相似文献
93.
94.
《Surface and interface analysis : SIA》2005,37(8):683-688
Heating (100) silicon at high temperature (say, higher than 850 °C) in H2, cooling to 670–700 °C in the same ambient, and quenching to room temperature in N2 results in environmentally robust, terraced 1 × 1 (100) SiH2. Evidence for this conclusion is based on angle‐resolved x‐ray photoelectron spectroscopy, atomic force microscopy, infrared absorption spectroscopy in the attenuated total reflection mode, thermal programmed desorption, and reflection high‐energy electron diffraction. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
95.
光学活性化合物的工业合成 总被引:9,自引:0,他引:9
本文介绍了光学活性化合物研究现状及发展趋势。并从技术和经济角度论述了工业合成光学活性化合物的可能性 相似文献
96.
Frost R. L. Weier M. L. Erickson Kristy L. 《Journal of Thermal Analysis and Calorimetry》2004,76(3):1025-1033
Struvite (NH4MgPO4·6H2O) is a mineral often found in urinary tracts and kidneys. Thermal decomposition using slow low heating shows that the 'kidney'
stone can be decomposed at temperatures below 40°C. At this temperature both ammonia and water are evolved. If more rapid
heating is employed the decomposition occurs at around 80°C. The implication of this work rests with the use of low slow heat
for the decomposition of the kidney stones.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
97.
98.
A new way for synthesizing styrenic type of chiral resins grafting to multidentate ligand has been found. The synthetic scheme is proved to be practical by means of elemental anaysis, IR spectra and metal adsorbility. The resolving power of the new chiral ligand resins coordinated with copper (Ⅱ) as stationary phases has been discussed based on HPLC, and some points of view about the compositions of mobil phase and mechanism of resolution are presented. 相似文献
99.
Resolution of enantiomers by HPLC on cellulose derivatives 总被引:4,自引:0,他引:4
Summary Various polysaccharide derivatives, particularly cellulose derivatives, were synthesized and used as chiral stationary phases
for optical resolution by HPLC after being adsorbed on macroporous silica gel. Cellulose triacetate (CTA-II), which was synthesized
under homogeneous conditions, showed a chiral recognition ability for many racemates. Other cellulose derivatives such as
cellulose tribenzoate (OB), cellulose-trisphenylcarbamate (OC), cellulose tribenzyl ether (OE), and cellulose tricinnamate
(OK) also showed unique chiral recognition. Among other polysaccharide derivatives, curdlan triacetate was also exhibited
an effective chiral recognition.
Presented at the 15th International Symposium on Chromatography, Nürnberg, October 1984 相似文献
100.
The effect of ohmic and conventional heat processing of different food products on their chemical and physical parameters
was studied. Depending on the food being analysed, parameters such as pH, total solids, ash, titratable acidity, ascorbic
acid, total sugars, total fatty acids, total phenolic compounds, and anthocyanins content were determined before and after
ohmic and conventional pasteurization techniques and the results were compared using one-way analysis of variance. In goat
milk samples treated by ohmic technology the pH value (6.58) and total fatty acids content in milk fat (86.5 mass %) were
comparable to those found in milk treated by conventional process, however, ohmically treated samples presented a lower content
of lactic acid, 0.13 %. In cloudberry jam samples treated by ohmic technology the results of some of the main parameters tested,
such as total sugar content 46.1 mass %, ascorbic acid content 2.83 mass %, and titratable acidity 6.01 mass % (as citric
acid) did not show significant differences when compared with samples treated by conventional technology.
Presented at the 33rd International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 22–26 May
2006. 相似文献