全文获取类型
收费全文 | 4289篇 |
免费 | 111篇 |
国内免费 | 12篇 |
专业分类
化学 | 3049篇 |
晶体学 | 52篇 |
力学 | 66篇 |
综合类 | 1篇 |
数学 | 224篇 |
物理学 | 1020篇 |
出版年
2023年 | 23篇 |
2022年 | 17篇 |
2021年 | 39篇 |
2020年 | 58篇 |
2019年 | 66篇 |
2018年 | 51篇 |
2017年 | 31篇 |
2016年 | 67篇 |
2015年 | 76篇 |
2014年 | 92篇 |
2013年 | 193篇 |
2012年 | 186篇 |
2011年 | 230篇 |
2010年 | 146篇 |
2009年 | 142篇 |
2008年 | 232篇 |
2007年 | 261篇 |
2006年 | 259篇 |
2005年 | 191篇 |
2004年 | 166篇 |
2003年 | 171篇 |
2002年 | 159篇 |
2001年 | 118篇 |
2000年 | 134篇 |
1999年 | 84篇 |
1998年 | 60篇 |
1997年 | 57篇 |
1996年 | 47篇 |
1995年 | 43篇 |
1994年 | 44篇 |
1993年 | 59篇 |
1992年 | 50篇 |
1991年 | 49篇 |
1990年 | 38篇 |
1989年 | 49篇 |
1988年 | 49篇 |
1987年 | 42篇 |
1986年 | 35篇 |
1985年 | 54篇 |
1984年 | 58篇 |
1983年 | 48篇 |
1982年 | 48篇 |
1981年 | 31篇 |
1980年 | 34篇 |
1979年 | 49篇 |
1978年 | 43篇 |
1977年 | 48篇 |
1975年 | 26篇 |
1974年 | 32篇 |
1967年 | 16篇 |
排序方式: 共有4412条查询结果,搜索用时 46 毫秒
111.
Computer programs are described that allow facile analysis of data from a protein sequencer and amino acid analyzer. The sequencer program provides automated sequence interpretation while requiring minimal user interaction. The program serves as a powerful aid in deciphering mixture sequences and allows routine monitoring of sequencer performance. The computer program for amino acid analysis data provides the following calculations: mole percent, protein concentration and residues per mole with comparison between theoretical and calculated values. A plot of molecular weight versus deviation from integer values is calculated providing a measure of peptide or protein purity. 相似文献
112.
SERS from crystal violet (CV) on a Ag electrode was investigated under preresonance and resonance conditions. The excitation profile of the chemisorbed species is like that of dissolved molecules but intensities are ≈ 1000 times larger. The Raman enhancement is ≈ 108 and exhibits a specific potential dependence even in the absence of adsorption-desorption process. At potentials where reduction of CV occurs leuco crystal violet was detected. 相似文献
113.
Summary The potential ranges of polarization of a pair of dropping mercury electrodes, over which the two mercury droplets coalesced, were measured as functions of ionic concentrations for various electrolytes. In the case of simple inorganic electrolytes the condition of coalescence obtained was proved to be in quantitative agreement with theVerwey-Overbeek theory of coagulation of lyophobic sols, thus indicating that the interaction between sub-microscopic particles of hydrophobic sols is essentially the same as that between macroscopic mercury droplets. While, in the case of sodium citrate solutions two kinds of marked deviations from the theory were observed, which appeared to be due to the specific adsorption of citrate ions and to the formation of protective interfacial films.
Zusammenfassung Die Potentialbereiche der Polariation eines Paares von Quecksilber-Tropfelektroden, über die die beiden Quecksilbertropfen koaleszieren, werden als Funktion der Ionenkonzentration verschiedener Elektrolyte gemessen. Im Fall einfacher anorganischer Elektrolyte wurde die erhaltene Bedingung der Koaleszenz mit der Theorie vonVerwey-Overbeek der Kaogulation lyophober Sole geprüft und in quantitativer übereinstimmung befunden. Das zeigt, da\ die Wechselwirkung zwischen submikroskopischen Partikeln hydrophober Sole im wesentlichen dieselbe ist wie zwischen den makroskopischen Quecksilbertröpfchen. Dagegen ergaben sich im Fall von Natriumzitratlösungen zwei Arten markanter Abweichungen von der Theorie. Diese scheinen spezifische Adsorption der Zitrationen und die Ausbildung von SchutzgrenzflÄchenfilmen zur Ursache zu haben.相似文献
114.
Chlorophyll derivatives possessing triethoxysilyl groups have been synthesized for the first time and grafted on mesoporous silica to construct an efficient energy transfer system between the chromophores. 相似文献
115.
116.
Koga T Taguchi K Kinoshita T Higuchi M 《Chemical communications (Cambridge, England)》2002,(3):242-243
A novel artificial protein with simple primary structure, poly(gamma-methyl-L-glutamate)-grafted polyallylamine, has been prepared and the resultant peptide has shown a unique property of pH-regulated conformation and morphology. 相似文献
117.
S. Watanabe N. S. Ishioka T. Sekine H. Kudo H. Shimomura H. Muramatsu T. Kume 《Journal of Radioanalytical and Nuclear Chemistry》2005,266(3):499-502
Summary Hydrophilic endohedral 133Xe-fullerenols, [133Xe@C60(OH)xand 133Xe@C70(OH)x], were synthesized from hydrophobic endohedral 133Xe-fullerenes. The yield of endohedral 133Xe-fullerenols extracted in water was about 40% and 23% for C60and C70, respectively. The products stored in 0.9% NaCl solution at 20 °C were stable enough to be used in nuclear medicine. 相似文献
118.
Silaned glass beads are applied to the preconcentration and spectrophotometric determination of phosphorus as the phosphomolybdenum blue complex. Traces of phosphorus in water are collected as a phosphomolybdenum blue complex on a column of the beads. The phosphomolybdenum blue is eluted with N,N-dimethylformamide and the absorbance of the eluate continuously monitored at 700 nm. The height of the very sharp peak obtained is proportional to the amount of phosphorus present and 0.1-0.5 mug of phosphorus in a 10-ml sample can be determined reproducibly. Interference from arsenate is eliminated by addition of a reducing agent. High concentrations of silica cause a small positive error. This method is applicable to the analysis of river water and sea-water samples. 相似文献
119.
120.
Tomoyuki Esumi 《Tetrahedron letters》2004,45(37):6941-6945
Isoplagiochin D, a highly strained macrocyclic bis(bibenzyls) with two biaryl units isolated from the liverwort Pladiochila fruticosa, was prepared in 10.6% overall yield for the 11 steps by an efficient synthetic approach involving the construction of two bibenzyl and one biaryl units using Horner-Wadsworth-Emmons and Suzuki-Miyaura protocols. 相似文献