全文获取类型
收费全文 | 9066篇 |
免费 | 448篇 |
国内免费 | 71篇 |
专业分类
化学 | 6111篇 |
晶体学 | 98篇 |
力学 | 300篇 |
数学 | 1179篇 |
物理学 | 1897篇 |
出版年
2024年 | 22篇 |
2023年 | 77篇 |
2022年 | 366篇 |
2021年 | 360篇 |
2020年 | 265篇 |
2019年 | 353篇 |
2018年 | 318篇 |
2017年 | 241篇 |
2016年 | 441篇 |
2015年 | 300篇 |
2014年 | 457篇 |
2013年 | 843篇 |
2012年 | 583篇 |
2011年 | 592篇 |
2010年 | 443篇 |
2009年 | 389篇 |
2008年 | 422篇 |
2007年 | 380篇 |
2006年 | 335篇 |
2005年 | 241篇 |
2004年 | 252篇 |
2003年 | 181篇 |
2002年 | 227篇 |
2001年 | 104篇 |
2000年 | 136篇 |
1999年 | 93篇 |
1998年 | 60篇 |
1997年 | 75篇 |
1996年 | 62篇 |
1995年 | 48篇 |
1994年 | 63篇 |
1993年 | 58篇 |
1992年 | 51篇 |
1991年 | 34篇 |
1990年 | 35篇 |
1989年 | 42篇 |
1988年 | 42篇 |
1987年 | 36篇 |
1986年 | 22篇 |
1985年 | 52篇 |
1984年 | 47篇 |
1983年 | 36篇 |
1982年 | 40篇 |
1981年 | 39篇 |
1980年 | 54篇 |
1979年 | 26篇 |
1978年 | 23篇 |
1977年 | 24篇 |
1976年 | 23篇 |
1975年 | 20篇 |
排序方式: 共有9585条查询结果,搜索用时 0 毫秒
991.
Paweł K. Zarzycki Magdalena M. ŚlączkaMagdalena B. Zarzycka Elżbieta WłodarczykMichał J. Baran 《Analytica chimica acta》2012
The main goal of present paper is to demonstrate the separation and detection capability of micro-TLC technique involving simple one step liquid extraction protocols of complex materials without multi-steps sample pre-purification. In the present studies target components (cyanobacteria pigments, lipids and fullerenes) were isolated from heavy loading complex matrices including spirulina dried cells, birds’ feathers and fatty oils as well as soot samples derived from biomass fuel and fossils-fired home heating systems. In each case isocratic separation protocol involving less that 1 mL of one component or binary mixture mobile phases can be completed within time of 5–8 min. Sensitive detection of components of interest was performed via fluorescence or staining techniques using iodine or phosphomolybdic acid. Described methodology can be applied for fast fractionation or screening of whole range of target substances as well as chemo-taxonomic studies and fingerprinting of complex mixtures, which are present in raw biological or environmental samples. 相似文献
992.
993.
994.
Islam Ullah Khan Tehseen Aman Muhammad Asif Iqbal Asrar Ahmad Kazi 《Mikrochimica acta》2000,134(1-2):27-31
Fluoxetine hydrochloride reacts with benzoyl peroxide and potassium iodide, after heating for 1 min at 30 °C, to give a blue
colour having maximum absorbance at 570 nm. The reaction is selective for fluoxetine with 0.01 mg/mL as visual limit of quantitation
and provides a basis for a new spectrophotometric determination. The colour reaction obeys Beer’s law from 0.1 mg/10 mL to
2.0 mg/10 mL of fluoxetine and the relative standard deviation is 0.68%. The qualitative assessment of tolerable amounts of
other drugs is also studied.
Received September 21, 1998. Revision September 10, 1999. 相似文献
995.
Tahir Ahmad Sabariah Baharun Khairil Anuar Arshad 《Journal of mathematical chemistry》2010,47(4):1263-1273
In this paper we have investigated and explored the realm of fuzzy graph in its relation to autocatalytic sets. A new concept
namely fuzzy autocatalytic set have been defined. This relation has produced some results in the forms of theorems which have
been proven. A clinical waste incineration process has been modeled using this new concept indicates to be more accurate than
using crisp graph. 相似文献
996.
997.
998.
999.
Corrosion of gadolinium and ytterbium in a molten eutectic mixture of lithium and potassium chlorides is studied in the present
work using the gravimetry and EMF methods. It is found that the corrosion rate of ytterbium is 3–5 times higher than that
of gadolinium under similar conditions. Satisfactory agreement between the current density values of gadolinium corrosion
calculated on the basis of the results of the gravimetric data and the values of steady-state potentials points to the electrochemical
mechanism of gadolinium corrosion in the LiCl-KCl melt. 相似文献
1000.
A. S. Abd‐El‐Aziz E. K. Todd G. Z. Ma 《Journal of polymer science. Part A, Polymer chemistry》2001,39(8):1216-1231
Soluble organoiron polyethers, thioethers, and amines were synthesized via nucleophilic aromatic substitution reactions. The synthesis of these classes of organometallic polymers involved either the reaction of cyclopentadienyliron complexes of dichloroarenes with various oxygen and sulfur dinucleophiles or the reaction of ether‐ or amine‐containing diiron complexes with dithiols. Polymerization reactions with the diiron complexes gave rise to organoiron polymers with alternating ether/thioether or amine/thioether bridges. Removal of the iron moieties from the backbone of these polymers allowed for the production of the corresponding organic materials. Furthermore, the organometallic polymers had much higher solubilities than their organic analogues. Thermogravimetric analysis of the organoiron polymers indicated that the polymers lost their metallic moieties at approximately 200 °C, whereas degradation of the polymer backbones occurred around 500 °C. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1216–1231, 2001 相似文献