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991.
Nondenaturing polyacrylamide gel electrophoresis to study the dissociation of the p53·MDM2/X complex by potentially anticancer compounds 下载免费PDF全文
Roberta Sgammato Doriana Desiderio Anna Lamberti Gennaro Raimo Ettore Novellino Alfonso Carotenuto Mariorosario Masullo 《Electrophoresis》2015,36(24):3101-3104
A new analytical method to study the dissociation of the complexes between the oncosuppressor p53 and its negative modulators murine double‐minute protein 2 (MDM2) or MDMX, is proposed. This technique is reliable to determine the dissociative power exerted by small molecules on the complex taking advantage of the appearance of migrating MDM2 or MDMX in a native polyacrylamide gel, when inhibitors are added to the complex mixture. Therefore, we propose this new approach to easily screen library of compounds, with potential pharmacological anticancer activity. 相似文献
992.
993.
Elena Barbaro Roberta Zangrando Marco Vecchiato Clara Turetta Carlo Barbante Andrea Gambaro 《Analytical and bioanalytical chemistry》2014,406(22):5259-5270
Amino acids represent a fraction of organic matter in marine and freshwater ecosystems, and a source of carbon, nitrogen and energy. l-Amino acids are the most common enantiomers in nature because these chiral forms are used during the biosynthesis of proteins and peptide. To the contrary, the occurrence of d-amino acids is usually linked to the presence of bacteria. We investigated the distribution of l- and d-amino acids in the lacustrine environment of Terra Nova Bay, Antarctica, in order to define their natural composition in this area and to individuate a possible relationship with primary production. A simultaneous chromatographic separation of 40 l- and d-amino acids was performed using a chiral stationary phase based on teicoplainin aglycone (chirobiotic tag). The chromatographic separation was coupled to two different mass spectrometers—an LTQ-Orbitrap XL (Thermo Fisher Scientific) and an API 4000 (ABSciex)—in order to investigate their quantitative performance. High-performance liquid chromatography coupled with mass spectrometry methods were evaluated through the estimation of their linear ranges, repeatability, accuracy and detection and quantification limits. The high-resolution mass spectrometer LTQ-Orbitrap XL presented detection limits between 0.4 and 7 μg?l ?1, while the triple quadrupole mass spectrometer API 4000 achieved the best detection limits reported in the literature for the quantification of amino acids (between 4 and 200 ng?l ?1). The most sensitive method, HPLC-API 4000, was applied to lake water samples. Figure
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994.
995.
Giuseppe Peddio Barbara Pittau Ilaria Manca Roberta Salis Luca Pani Luigi Pira 《Chromatographia》2014,77(1-2):75-82
A sensitive and selective LC–MS/MS method for the quantification of the atypical antipsychotic agent quetiapine and its metabolite norquetiapine (N-desalkyl quetiapine) was developed and validated. Following the protein precipitation technique, the analytes were separated using a reversed phase column with gradient elution. The compounds were ionized in the electrospray positive ionization (ESI+) ion source tandem MS detection in multiple reaction monitoring (MRM) mode. Calibration curves were generated by plotting the peak area ratio of quetiapine and norquetiapine to the IS clozapine for each calibration concentration. The method provides a linear response from a quantitation range of 2.3–452.9 nM (0.9–173.7 ng/mL) and 2.7–543.0 nM (1.0–200.0 ng/mL) for quetiapine and norquetiapine, respectively. Regression analysis showed a correlation coefficient greater than 0.999 and 0.991 for quetiapine and norquetiapine, respectively. To evaluate the metabolism of quetiapine by the cytochrome P450 in microsomes, the method has been subsequently employed. LC–MS/MS procedure has been carried out to determine increasing concentrations of both drugs in microsomal matrix obtained by a pool of mammalian liver microsomes BD UltraPoolTM Human Liver Microsomes (HLM 150). 相似文献
996.
997.
Andrea Nava Dr. Luca Rigamonti Prof. Ennio Zangrando Prof. Roberta Sessoli Dr. Wolfgang Wernsdorfer Prof. Andrea Cornia 《Angewandte Chemie (International ed. in English)》2015,54(30):8777-8782
Tetrairon(III) single‐molecule magnets [Fe4(pPy)2(dpm)6] ( 1 ) (H3pPy=2‐(hydroxymethyl)‐2‐(pyridin‐4‐yl)propane‐1,3‐diol, Hdpm=dipivaloylmethane) have been deliberately organized into supramolecular chains by reaction with RuIIRuII or RuIIRuIII paddlewheel complexes. The products [Fe4(pPy)2(dpm)6][Ru2(OAc)4](BF4)x with x=0 ( 2 a ) or x=1 ( 2 b ) differ in the electron count on the paramagnetic diruthenium bridges and display hysteresis loops of substantially different shape. Owing to their large easy‐plane anisotropy, the s=1 diruthenium(II,II) units in 2 a act as effective seff=0 spins and lead to negligible intrachain communication. By contrast, the mixed‐valent bridges (s=3/2, seff=1/2) in 2 b introduce a significant exchange bias, with concomitant enhancement of the remnant magnetization. Our results suggest the possibility to use electron transfer to tune intermolecular communication in redox‐responsive arrays of SMMs. 相似文献
998.
Frontispiece: Sugar–Protein Connectivity Impacts on the Immunogenicity of Site‐Selective Salmonella O‐Antigen Glycoconjugate Vaccines 下载免费PDF全文
999.
Neuza Jorge Ana Carolina da Silva Cassia Roberta Malacrida 《Natural product research》2015,29(24):2313-2317
Oils extracted from Cucurbitaceae seeds were characterised for their fatty acid and tocopherol compositions. In addition, some physicochemical characteristics, total phenolic contents and the radical-scavenging activities were determined. Oil content amounted to 23.9% and 27.1% in melon and watermelon seeds, respectively. Physicochemical characteristics were similar to those of other edible oils and the oils showed significant antioxidant activities. Fatty acid composition showed total unsaturated fatty acid content of 85.2–83.5%, with linoleic acid being the dominant fatty acid (62.4–72.5%), followed by oleic acid (10.8–22.7%) and palmitic acid (9.2–9.8%). The oils, especially watermelon seed oil, showed high total tocopherol and phenolic contents. The γ-tocopherol was the predominant tocopherol in both oils representing 90.9 and 95.6% of the total tocopherols in melon and watermelon seed oils, respectively. The potential utilisation of melon and watermelon seed oils as a raw material for food, chemical and pharmaceutical industries appears to be favourable. 相似文献
1000.
Discriminating Halogen‐Bonding from Other Noncovalent Interactions by a Combined NOE NMR/DFT Approach 下载免费PDF全文
Dr. Gianluca Ciancaleoni Prof. Roberta Bertani Dr. Luca Rocchigiani Dr. Paolo Sgarbossa Dr. Cristiano Zuccaccia Prof. Alceo Macchioni 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(1):440-447
Herein a combined NOE NMR/DFT methodology to discriminate between adducts held together by halogen bonding (XB) and other noncovalent interactions (non‐XB, such as lone pair/π), based on the determination of the XB donors′ and acceptors′ relative orientation, is proposed. In particular, 19F,1H HOESY NMR spectroscopy experiments and DFT calculations on different XB donors, such as perfluorohexyl iodide ( I1 ), iodopentafluorobenzene ( I2 ) and bromopentafluorobenzene ( Br ), combined with different Lewis bases, such as 1,4‐diazabicyclo[2.2.2]octane ( DABCO ) and 2,4,6‐trimethylpyridine ( Me3Py ), were performed. The results clearly show that in the case DABCO / I1 the XB adduct is practically the only one present in solution, whereas for the other pairs a certain amount of non‐XB adduct is present. Combining DFT and HOESY results, the amount of non‐XB adducts can be roughly quantified under our experimental conditions as 4 % for DABCO / I2 , between 10 and 20 % for Me3Py / I1 and Me3Py / I2 , and 44 % for DABCO / Br. 相似文献