全文获取类型
收费全文 | 283篇 |
免费 | 5篇 |
专业分类
化学 | 238篇 |
晶体学 | 3篇 |
力学 | 3篇 |
数学 | 19篇 |
物理学 | 25篇 |
出版年
2023年 | 3篇 |
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 10篇 |
2018年 | 6篇 |
2017年 | 2篇 |
2016年 | 5篇 |
2015年 | 6篇 |
2014年 | 10篇 |
2013年 | 23篇 |
2012年 | 22篇 |
2011年 | 19篇 |
2010年 | 19篇 |
2009年 | 13篇 |
2008年 | 21篇 |
2007年 | 19篇 |
2006年 | 19篇 |
2005年 | 26篇 |
2004年 | 15篇 |
2003年 | 10篇 |
2002年 | 8篇 |
2001年 | 6篇 |
2000年 | 3篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1993年 | 2篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1981年 | 2篇 |
1979年 | 4篇 |
排序方式: 共有288条查询结果,搜索用时 15 毫秒
41.
Hoffmann-Emery F Hilpert H Scalone M Waldmeier P 《The Journal of organic chemistry》2006,71(5):2000-2008
A new efficient synthesis of two novel classes of NK1 receptor antagonists, among them befetupitant and netupitant, starting from 6-chloronicotinic acid is described. The introduction of the o-tolyl substituent at C4 of the pyridine ring was achieved by a one-pot selective 1,4-Grignard addition/oxidation sequence to 6-chloronicotinic acid or a derivative of it. The scope of this addition/oxidation sequence was examined. It was also shown that the carboxylic function can be converted to a methyl amino group by a Hofmann rearrangement followed by reduction. Furthermore, a new high-yielding synthesis of 2-(3,5-bistrifluoromethylphenyl)-2-methyl propionic acid based on the carbonylation of the tertiary alcohol obtained by Grignard addition of 3,5-bis(trifluoromethyl)bromobenzene to acetone was established. 相似文献
42.
Tjasa Vrlinic Dominique Debarnot Gilbert Legeay Arnaud Coudreuse Benaissa El Moualij Willy Zorzi Armand Perret‐Liaudet Isabelle Quadrio Miran Mozetic Fabienne Poncin‐Epaillard 《Macromolecular bioscience》2012,12(6):830-839
New non‐fouling tubes are developed and their influence on the adhesion of neuroproteins is studied. Recombinant prion proteins are considered as a single component representative of hydrophobic proteins. Samples are stored for 24 h at 4 °C in tubes coated with two different coatings: poly(N‐isopropylacrylamide) as a hydrophilic surface and a plasma‐fluorinated coating as a hydrophobic one. The protein adhesion is monitored by ELISA tests, XPS and confocal microscopy. It appears that the highest recovery of recombinant prion protein in the liquid phase is obtained with the hydrophilic surface while the hydrophobic character of the storage tube induces an important amount of biological loss. However, the recovery is not complete even for tubes coated with poly(N‐isopropylacrylamide).
43.
Versace F Uppugunduri CR Krajinovic M Théorêt Y Gumy-Pause F Mangin P Staub C Ansari M 《Analytical and bioanalytical chemistry》2012,404(6-7):1831-1838
The role of busulfan (Bu) metabolites in the adverse events seen during hematopoietic stem cell transplantation and in drug interactions is not explored. Lack of availability of established analytical methods limits our understanding in this area. The present work describes a novel gas chromatography-tandem mass spectrometric assay for the analysis of sulfolane (Su) in plasma of patients receiving high-dose Bu. Su and Bu were extracted from a single 100 μL plasma sample by liquid-liquid extraction. Bu was separately derivatized with 2,3,5,6-tetrafluorothiophenolfluorinated agent. Mass spectrometric detection of the analytes was performed in the selected reaction monitoring mode on a triple quadrupole instrument after electronic impact ionization. Bu and Su were analyzed with separate chromatographic programs, lasting 5?min each. The assay for Su was found to be linear in the concentration range of 20-400?ng/mL. The method has satisfactory sensitivity (lower limit of quantification, 20?ng/mL) and precision (relative standard deviation less than 15?%) for all the concentrations tested with a good trueness (100?±?5?%). This method was applied to measure Su from pediatric patients with samples collected 4?h after dose 1 (n?=?46), before dose 7 (n?=?56), and after dose 9 (n?=?54) infusions of Bu. Su (mean?±?SD) was detectable in plasma of patients 4?h after dose 1, and higher levels were observed after dose 9 (249.9?±?123.4?ng/mL). This method may be used in clinical studies investigating the role of Su on adverse events and drug interactions associated with Bu therapy. 相似文献
44.
Gómez-Graña S Hubert F Testard F Guerrero-Martínez A Grillo I Liz-Marzán LM Spalla O 《Langmuir : the ACS journal of surfaces and colloids》2012,28(2):1453-1459
Gold nanorods in aqueous solution are generally surrounded by surfactants or capping agents. This is crucial for anisotropic growth during synthesis and for their final stability in solution. When CTAB is used, a bilayer has been evidenced from analytical methods even though no direct morphological characterization of the precise thickness and compactness has been reported. The type of surfactant layer is also relevant to understand the marked difference in further self-assembling properties of gold nanorods as experienced using 16-EO(1)-16 gemini surfactant instead of CTAB. To obtain a direct measure of the thickness of the surfactant layer on gold nanorods synthesized by the seeded growth method, we coupled TEM, SAXS, and SANS experiments for the two different cases, CTAB and gemini 16-EO(1)-16. Despite the strong residual signal from micelles in excess, it can be concluded that the thickness is imposed by the chain length of the surfactant and corresponds to a bilayer with partial interdigitation. 相似文献
45.
46.
Tuncel S Fournier-dit-Chabert J Albrieux F Ahsen V Ducki S Dumoulin F 《Organic & biomolecular chemistry》2012,10(6):1154-1157
A phthalocyanine-chalcone conjugate has been designed to combine the vascular disrupting effect of chalcones with the photodynamic effect of phthalocyanines. This potential dual photodynamic and antiangiogenic agent was obtained by the condensation of a tetrahydroxylated non-peripherally substituted Zn(ii) phthalocyanine with an amino chalcone converted into the corresponding activated isocyanate. The conjugate was fully characterized. 相似文献
47.
B Kintses C Hein MF Mohamed M Fischlechner F Courtois C Lainé F Hollfelder 《Chemistry & biology》2012,19(8):1001-1009
Highlights? Microfluidic droplet compartments miniaturize cell lysate screening assays ? Picoliter single-cell lysate assays comparable in sensitivity to macroscale ? Directed evolution results in improved clones validating this experimental set-up ? Precision of droplet sorting enables enrichment of clones with slight improvements 相似文献
48.
Rima Laroum Fabienne Berrée Thierry Roisnel Vincent Dorcet Bertrand Carboni Abdelmadjid Debache 《Tetrahedron letters》2019,60(35):150988
The AlCl3-promoted reactions of cycloalkanones with hydrazones are described. This approach represents a mild and operationally simple method to access 2,3-diaryl-4,5,6,7-tetrahydro-1H-indazoles and their analogues in good to moderate yields. 相似文献
49.
The anomeric hydroxyl of lactose was carbamoylated selectively by treating the free sugar with alkylisocyanates, thus without preliminary protection of the other hydroxyls of the lactose molecule. Moreover, the readily available 1-aminolactose and 1-octyl-aminolactose reacted with isocyanates and isothiocyanates to afford selectively -lactosyl -alkylureas and -lactosyl -alkylthioureas, respectively. 相似文献
50.
Treatment of substituted 1,3-oxathiolanes with ethyl (triethylsilyl)diazoacetate in the presence of a copper catalyst effects one-carbon ring expansion to the corresponding 3-triethylsilyl-1,4-oxathiane-3-carboxylates. Subsequent desilylation can be brought about by treatment with tetrabutylammonium fluoride. 相似文献