全文获取类型
收费全文 | 9815篇 |
免费 | 261篇 |
国内免费 | 20篇 |
专业分类
化学 | 5825篇 |
晶体学 | 162篇 |
力学 | 267篇 |
数学 | 733篇 |
物理学 | 3109篇 |
出版年
2023年 | 94篇 |
2022年 | 211篇 |
2021年 | 161篇 |
2020年 | 177篇 |
2019年 | 240篇 |
2018年 | 207篇 |
2017年 | 232篇 |
2016年 | 317篇 |
2015年 | 212篇 |
2014年 | 400篇 |
2013年 | 781篇 |
2012年 | 548篇 |
2011年 | 655篇 |
2010年 | 417篇 |
2009年 | 405篇 |
2008年 | 460篇 |
2007年 | 440篇 |
2006年 | 335篇 |
2005年 | 281篇 |
2004年 | 229篇 |
2003年 | 163篇 |
2002年 | 183篇 |
2001年 | 117篇 |
2000年 | 125篇 |
1999年 | 86篇 |
1998年 | 56篇 |
1997年 | 56篇 |
1996年 | 92篇 |
1995年 | 104篇 |
1994年 | 98篇 |
1993年 | 92篇 |
1992年 | 120篇 |
1991年 | 86篇 |
1990年 | 79篇 |
1989年 | 92篇 |
1988年 | 87篇 |
1987年 | 90篇 |
1986年 | 74篇 |
1985年 | 104篇 |
1984年 | 119篇 |
1983年 | 82篇 |
1982年 | 98篇 |
1981年 | 97篇 |
1980年 | 102篇 |
1979年 | 90篇 |
1978年 | 102篇 |
1977年 | 84篇 |
1976年 | 56篇 |
1975年 | 61篇 |
1974年 | 74篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
181.
A general microcantilever surface modification method using a multilayer for biospecific recognition
The key to microcantilever surface modification technology is to selectively modify one side of a microcantilever surface with molecular recognition layers. In this paper, we report a general microcantilever modification method using a multilayer film. 相似文献
182.
The biomimetic reduction of anti-inflammatory drug, nimesulide (1) with sodium borohydride catalyzed by 5,10,15,20-tetraarylporphyrinatoiron(III) chlorides [TAPFe(III)Cl] has been studied in organic solvents under anaerobic and aerobic conditions. 相似文献
183.
A rapid and simple RP-TLC method for simultaneous quantification of pharmacologically important sesquiterpene artemisinin (AM) together with its precursors arteannuin-B (AB) and artemisinic acid (AA) in the inflorescence part of Artemisia annua plant has been developed. The RP-TLC of sesquiterpenes was performed on RP-18 F254 S thin-layer chromatographic plates by developing in mobile phase, containing 0.2% TFA in water/ACN (35:65, v/v). The densitometric determination of AM, AB and AA was carried out after derivatization with anisaldehyde reagent at 426 nm in absorption-reflectance mode. 相似文献
184.
The isotropic ESR spectra of a number of phosphonyl radicals (X2O), the dimethylphosphinyl radical, and the phosphoranyl radical (MeO)3OBu-t, are described, and accurate values of the phosphorus hyperfine splittings and g-factors are reported. For X2O, the value of a(P) increases and the g-factor decreases as the electronegativity of X increases. There is a linear relationship between a(P) for X2O and 1J(PH) for X2P(O)H, but the same relationship does not hold for Me2P- and Me2PH. The spectrum of the di-n-hexylphosphonyl radical shows coupling to two pairs of α-methylene protons, and this non-equivalence is attributed to the pyramidal structure of the phosphonyl radical. 相似文献
185.
Singh P Lillywhite B Bannaghan C Broad P 《Combinatorial chemistry & high throughput screening》2005,8(4):319-325
IMAP is a fluorescence polarisation-based assay method which can be applied to the measurement of protein kinase activity. Using a model serine/threonine kinase we found that IMAP generated a good assay window (Z' > 0.8), was very tolerant of DMSO, and was flexible with respect to sample processing (stopped reactions were stable over a period of several days). Using a set of six low molecular weight inhibitors of the kinase, we found a good correlation between IMAP and scintillation proximity assay (SPA) potency data. IMAP, which measures product accumulation, was compared in an HTS setting with a substrate depletion method (luminescence-based measurement of ATP concentration). There was a reasonable (approximately 50%) overlap in primary hits from a 17,000 compound set, but more apparent false positives were generated from the IMAP method. We followed up the compounds that showed activity in the IMAP method but not in the luminescence assay. Approximately 10% of these compounds displayed intrinsic fluorescence, suggesting that they were false actives by virtue of intrinsic spectroscopic properties. Compound activity by competition of phosphopeptide binding to IMAP beads can occur with high concentrations of chelating compounds, but did not occur with any of the false actives, suggesting that this form of interference is rare. 相似文献
186.
187.
This is a corrigendum to our paper, "On a class of prime entire functions", published in Acta Math. Sin., Engl. Ser., 25, 1647-1652 (2009). 相似文献
188.
R. Singh R. M. Misra D. C. Gupta D. D. Shukla M. N. Sharma M. P. Madan 《Zeitschrift für Physik B Condensed Matter》1985,58(2):83-89
The parameterC
1=[(1/K
T
)/P]
T
, which describes the pressure variation of the compressibility, has been examined correlating the thermodynamical and interatomic potential approaches employing fewer approximations than has been usual heretofore. General expressions have been derived forC
1 by including the thermal correction terms, which have generally been ignored in previous studies concerning thermal properties of ionic crystals. The parameterC
1 has also been related to the Grüneisen parameter, , using a relation given earlier. The applicability of the derived equations is investigated and discussed for alkali halides employing few realistic potential forms. A good general accord is found with the available experimental data, which exhibits an essential improvement over other theoretical determinations. 相似文献
189.
Using the Wigner-Kirkwood expansion and bare Lennard-Jones (LJ) (12-6) potential, an effectiveLJ potential is derived, which includes the quantum effects through the expressions of the effective diameter∂(T, λ) and well-depth
(T, λ). We use theWCA perturbation theory to calculate the free energy and pressure for theLJ and effectiveLJ potentials. Simple analytic expressions are given for the reference system and the first order correction calculated. The
results are quite good at high density. The quantum effects on the free energy and pressure are also discussed. 相似文献
190.