全文获取类型
收费全文 | 2968篇 |
免费 | 119篇 |
专业分类
化学 | 1576篇 |
晶体学 | 16篇 |
力学 | 57篇 |
数学 | 388篇 |
物理学 | 1050篇 |
出版年
2021年 | 33篇 |
2020年 | 33篇 |
2019年 | 32篇 |
2016年 | 112篇 |
2015年 | 115篇 |
2014年 | 150篇 |
2013年 | 287篇 |
2012年 | 104篇 |
2011年 | 80篇 |
2010年 | 84篇 |
2009年 | 63篇 |
2008年 | 64篇 |
2007年 | 40篇 |
2006年 | 86篇 |
2005年 | 29篇 |
2004年 | 31篇 |
2003年 | 33篇 |
2002年 | 48篇 |
2001年 | 36篇 |
2000年 | 59篇 |
1999年 | 37篇 |
1998年 | 43篇 |
1997年 | 38篇 |
1996年 | 39篇 |
1995年 | 42篇 |
1994年 | 37篇 |
1993年 | 39篇 |
1992年 | 31篇 |
1991年 | 34篇 |
1990年 | 35篇 |
1989年 | 27篇 |
1988年 | 51篇 |
1987年 | 39篇 |
1986年 | 35篇 |
1985年 | 56篇 |
1984年 | 56篇 |
1983年 | 37篇 |
1982年 | 32篇 |
1981年 | 32篇 |
1980年 | 41篇 |
1979年 | 40篇 |
1978年 | 39篇 |
1977年 | 49篇 |
1976年 | 48篇 |
1975年 | 42篇 |
1974年 | 56篇 |
1973年 | 37篇 |
1972年 | 29篇 |
1969年 | 28篇 |
1962年 | 27篇 |
排序方式: 共有3087条查询结果,搜索用时 15 毫秒
1.
Tomáš Hložek Martin Štícha Miroslava Bursová Ivan Jelínek Petr Tůma Radomír Čabala 《Electrophoresis》2020,41(18-19):1564-1567
Riociguat is novel antihypertensive drug for treatment of pulmonary hypertension. As such, it is still being tested in many clinical and pharmacokinetic trials. Existing methods that determine serum riociguat and desmethylriociguat (DMR) are based solely on liquid chromatography with mass spectrometry. Therefore, we present a novel capillary electrophoresis with mass spectrometry method (CE-MS) for their determination in human serum as alternative method for ongoing trials. Complete resolution of both analytes was achieved by means of pH optimization of ammonium formate background electrolytes that are fully compatible with ESI/MS detection. Simple liquid-liquid extraction was used as sample pretreatment. The calibration dependence of the method was linear (in the range of 10–1000 ng/mL), with adequate accuracy (90.1–114.9%) and precision (13.4%). LOD and LOQ were arbitrarily set at 10 ng/mL for both analytes. Clinical applicability was validated using serum samples from patients treated with riociguat in pharmacokinetic study and the results corresponded with reference HPLC-MS/MS values. Capillary electrophoresis proved to be sensitive and selective tool for the analysis of riociguat and DMR. 相似文献
2.
A protocol to correct for intra‐ and interspecific variation in tail hair growth to align isotope signatures of segmentally cut tail hair to a common time line 下载免费PDF全文
3.
Dr. Liat Avram Dr. Václav Havel Ronit Shusterman-Krush Dr. Mark A. Iron Dr. Moritz Zaiss Prof. Vladimír Šindelář Dr. Amnon Bar-Shir 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(7):1687-1690
The accumulated knowledge regarding molecular architectures is based on established, reliable, and accessible analytical tools that provide robust structural and functional information on assemblies. However, both the dynamicity and low population of noncovalently interacting moieties within studied molecular systems limit the efficiency and accuracy of traditional methods. Herein, the use of a saturation transfer-based NMR approach to study the dynamic binding characteristics of an anion to a series of synthetic receptors derived from bambusuril macrocycles is demonstrated. The exchange rates of BF4− are mediated by the side chains on the receptor (100 s−1<kex<5000 s−1), which play a critical role in receptor-anion binding dynamics. The signal amplification obtained with this approach allows for the identification of different types of intermolecular interactions between the receptor and the anion, something that could not have been detected by techniques hitherto used to study molecular assemblies. These findings, which are supported by a computational molecular dynamic study, demonstrate the uniqueness and added value of this NMR method. 相似文献
4.
5.
Palladium and molybdenum polycrystalline layers (clusters) have been deposited in a stainless steel UHV system onto a layer of alumina (Al2O3). This layer has been prepared by high temperature oxidation of an aluminium layer. The interaction of this system with nitrogen has been investigated at room temperature by an FEM technique. Under these conditions nitrogen spillover from molybdenum to palladium has been observed. 相似文献
6.
V. Balek T. Mitsuhashi I.M. Bountseva H. Haneda Z. Malek J. Šubrt 《Journal of Sol-Gel Science and Technology》2003,26(1-3):185-189
The diffusion structural analysis (DSA) was used to characterize microstructure changes of hydrous titania gel films under in situ conditions of heating. TG and DTA were used in order to elucidate the processes controlling the formation of anatase film during heating of hydrous titania gel film. The annealing of porosity and near surface structure defects of the dehydrated titania films was indicated by DSA in the temperature range 255–700°C as the decrease of radon release rate. It was demonstrated that the annealing was enhanced on heating in oxygen in comparison with heating in argon. The DSA experimental results were compared with model curves describing the radon diffusion mobility and the annealing of radon diffusion paths. 相似文献
7.
N. Raju T. Špaček J. Ježek I. M. Caminiti F. Leinisch K. Hideg P. Ježek W. E. Trommer 《Applied magnetic resonance》2006,30(3-4):373-383
Electron paramagnetic resonance (EPR) spectroscopy of spin-labeled fatty acids was used to investigate their interaction withEscherichia coli-expressed human mitochondrial uncoupling protein UCP2 refolded from inclusion bodies in nonaethylene glycol monododecyl ether (C12E9) micelles. 5-DOXYL-stearic acid and 4-PROXYL-palmitic acid bound to UCP2 exhibited additional clearly separated h+1I, h?1I “immobile” peaks in the low- and high-field region, respectively, separated by 42 and 44 Gauss, and extensively reduced h+1M, h?1M “mobile” peaks, separated by about 30 G, whereas with 7-DOXYL-stearic acid the I and M peaks were smoothed together into one wide peak. Competition of 4-PROXYL-palmitic acid with added palmitic acid, arachidonic acid, and all-cis-8,11,14-eicosatrienoic acid and of 7-DOXYL-stearic acid with arachidonic acid was indicated by the disappearance of the h+1I, h?1I “immobile” peaks, whereas redistribution in micelles without protein was indicated by the rising of the h+1M, h?1M “mobile” peaks. In conclusion, a competition of palmitic, arachidonic, and eicosatrienoic acid within a putative fatty acid binding site was observed for mitochondrial uncoupling protein UCP2. This finding together with the observation of EPR spectra of highly immobilized probes exclusively in the presence of the recombinant UCP2 suggest the existence of a fatty acid binding site on UCP2 which is a prerequisite of the fatty acid cycling mechanism as previously postulated for UCP1. 相似文献
8.
Peter Šimon 《Journal of Thermal Analysis and Calorimetry》2006,83(3):521-522
This
issue of Journal of Thermal Analysis and Calorimetry contains selected papers
based on presentations in the field of thermal characteristics of advanced
polymer systems presented at the 8th International
Symposium on Polymers for Advanced Technologies (PAT 2005) held in Budapest,
September 2005.
Guest Editors 相似文献
9.
Presented by R. Freese. 相似文献
10.
The sulphur K-edge x-ray absorption spectra of SO2 multilayer and of SO2 submonolayer adsorbed on Cu(100) are analysed. It is found that the dominant spectral features are of a molecular origin. The results support earlier findings that the SO2 molecule stands perpendicular to the surface. Use of non-selfconsistent potentials does not lead to a good quantitative agreement between theory and experiment. 相似文献