全文获取类型
收费全文 | 109篇 |
免费 | 2篇 |
专业分类
化学 | 104篇 |
力学 | 3篇 |
物理学 | 4篇 |
出版年
2023年 | 1篇 |
2022年 | 4篇 |
2021年 | 9篇 |
2020年 | 3篇 |
2019年 | 8篇 |
2018年 | 5篇 |
2017年 | 1篇 |
2016年 | 5篇 |
2015年 | 1篇 |
2014年 | 2篇 |
2013年 | 16篇 |
2012年 | 5篇 |
2011年 | 5篇 |
2010年 | 4篇 |
2009年 | 2篇 |
2008年 | 4篇 |
2007年 | 2篇 |
2006年 | 6篇 |
2005年 | 3篇 |
2004年 | 5篇 |
2003年 | 5篇 |
2002年 | 4篇 |
2001年 | 1篇 |
2000年 | 6篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有111条查询结果,搜索用时 15 毫秒
51.
Roza B. Aisina Liliya I. Moukhametova Ekaterina F. Firsova Sergei D. Varfolomeyev 《Applied biochemistry and biotechnology》2000,88(1-3):137-143
Two acyl-derivatives of urokinase, p-trimethylam inocinnamoyl-urokinase (TMAC-Uk) and p-guanidinobenzoyl-urokinase (GB-Uk), reactivating with different rates (k reac were 6×10?4/s and 6×10?5/s, respectively) were prepared. In comparison with free urokinase, acyl-activators were more stable in human plasma, and their stability increased with the decrease in the reactivation rate. Plasma clotlysis induced by all three agents was time- and dose-dependent, but acyl-activators caused a more prolonged fibrinolysis and lengthened lag-phase than free urokinase. Slowly reactivating GB-Uk induced the most long-lasting clotlysis, whereas free urokinase was more effective for the first 3 h. A combination of GB-Uk with low dose urokinase promoted the long-lasting clotlysis with the shortened lag-phase. 相似文献
52.
Shakhmaeva II Saifullina DV Sattarova LI Abdullin TI 《Analytical and bioanalytical chemistry》2011,401(8):2591-2597
We designed an electrochemical sensor based on a carbon nanotube modified electrode (ME) to analyze DNA-cleaving activity.
The cleavage of high molecular weight DNA resulted in an increase in the oxidation current from DNA guanine nucleotides due
to a change in DNA adsorptive behavior on the surface of the ME. DNA digestion with DNAse I was accompanied by a linear increase
in the DNA signal in proportion to the enzyme activity. We then proposed an assay based on the sensor for the direct assessment
of the total deoxyribonuclease activity of blood serum as well as the separate detection of DNAse I and DNA abzymes. The assay
was applied to analyze deoxyribonucleases in sera from 21 healthy donors and 17 patients with autoimmune thyroiditis. Our
results show that the response of the sensor to DNA cleavage by blood deoxyribonucleases is a promising diagnostic criterion
for autoimmune thyroiditis. This sensor can be implemented in a disposable screen-printed electrode format for application
in clinical laboratories. 相似文献
53.
Dilyara R. Chulakova Ambara R. Pradipta Olga A. Lodochnikova Danil R. Kuznetsov Kseniya S. Bulygina Ivan S. Smirnov Konstantin S. Usachev Liliya Z. Latypova Almira R. Kurbangalieva Katsunori Tanaka 《化学:亚洲杂志》2019,14(22):4048-4054
The chiral substituted 1,5‐diazacyclooctane (1,5‐DACO) is of considerable importance and has attracted attention from a wide range of fields due to their unique chemical and biological properties. Despite the application potential, further study has not been optimized due to difficulties in their synthetic accessibility. Here, we report that the 1,5‐DACO bearing a chiral auxiliary obtained from the formal [4+4] cycloaddition of N‐alkyl‐α,β‐unsaturated imines can be further derivatized by nucleophilic alkylation to give various chiral substituted 1,5‐DACO derivatives. The removal of the chiral auxiliary was effectively carried out using hydrogenation over Pearlman's catalyst. This methodology allows the production of a broad range of unprecedented optically active 2,6‐dialkyl‐1,5‐DACO, which could not be accessed by other methods. 相似文献
54.
Gross Z Golubkov G Simkhovich L 《Angewandte Chemie (International ed. in English)》2000,39(22):4045-4047
55.
The study made in [1] revealed that the Poiseuille flow of a viscoplastic fluid is stable with respect to infinitely small perturbations. At the same time, it is a known fact that at large Reynolds numbers a turbulent-flow regime of a viscoplastic fluid has been observed experimentally (see [2]). The divergence in the results from the linear theory of hydrodynamic stability of the experimental data indicates the need for investigating the stability of the Poiseuille flow of a viscoplastic fluid with respect to finite amplitude perturbations; this forms the main content of the present paper. 相似文献
56.
Dr. Yulia B. Dudkina Dr. Alexey A. Kalinin Dr. Guzel M. Fazleeva Dr. Sirina M. Sharipova Dr. Liliya N. Islamova Dr. Alexey B. Dobrynin Dr. Daut R. Islamov Dr. Alina I. Levitskaya Prof. Dr. Marina Yu. Balakina Prof. Dr. Yulia H. Budnikova 《Chemphyschem》2021,22(22):2313-2328
A series of D-π-A, D-π-D′-π-A, D-π-A′-π-A nonlinear optical chromophores with vinylene π-electron bridges or bridges with π-deficient/π-excessive heterocyclic moieties along with the corresponding precursors D-vinylene, D-π-D′, D′-π-A, D-π-A′ and A′-π-A are synthesized and studied both experimentally and computationally. The effect of the heterocycle in the π-electron bridge on the oxidation/reduction potentials and the energy gap (ΔEel) is investigated in detail. The properties of the D-π-A′(D′)-π-A chromophores are shown to correlate with those of building blocks: the oxidation potential is determined by the D-vinylene, and the reduction potential is determined by A′(D′)-π-A truncated compounds. The contribution of the acceptor to the oxidation potential of chromophores in comparison with those of the precursors was estimated and analyzed in terms of electronic communication between the end groups. A good correlation between the ΔEel and the chromophores’ first hyperpolarizability is revealed. 相似文献
57.
Stepan S. Basok Igor A. Schepetkin Andrei I. Khlebnikov Anatoliy F. Lutsyuk Tatiana I. Kirichenko Liliya N. Kirpotina Victor I. Pavlovsky Klim A. Leonov Darya A. Vishenkova Mark T. Quinn 《Molecules (Basel, Switzerland)》2021,26(8)
Synthetic and natural ionophores have been developed to catalyze ion transport and have been shown to exhibit a variety of biological effects. We synthesized 24 aza- and diaza-crown ethers containing adamantyl, adamantylalkyl, aminomethylbenzoyl, and ε-aminocaproyl substituents and analyzed their biological effects in vitro. Ten of the compounds (8, 10–17, and 21) increased intracellular calcium ([Ca2+]i) in human neutrophils, with the most potent being compound 15 (N,N’-bis[2-(1-adamantyl)acetyl]-4,10-diaza-15-crown-5), suggesting that these compounds could alter normal neutrophil [Ca2+]i flux. Indeed, a number of these compounds (i.e., 8, 10–17, and 21) inhibited [Ca2+]i flux in human neutrophils activated by N-formyl peptide (fMLF). Some of these compounds also inhibited chemotactic peptide-induced [Ca2+]i flux in HL60 cells transfected with N-formyl peptide receptor 1 or 2 (FPR1 or FPR2). In addition, several of the active compounds inhibited neutrophil reactive oxygen species production induced by phorbol 12-myristate 13-acetate (PMA) and neutrophil chemotaxis toward fMLF, as both of these processes are highly dependent on regulated [Ca2+]i flux. Quantum chemical calculations were performed on five structure-related diaza-crown ethers and their complexes with Ca2+, Na+, and K+ to obtain a set of molecular electronic properties and to correlate these properties with biological activity. According to density-functional theory (DFT) modeling, Ca2+ ions were more effectively bound by these compounds versus Na+ and K+. The DFT-optimized structures of the ligand-Ca2+ complexes and quantitative structure-activity relationship (QSAR) analysis showed that the carbonyl oxygen atoms of the N,N’-diacylated diaza-crown ethers participated in cation binding and could play an important role in Ca2+ transfer. Thus, our modeling experiments provide a molecular basis to explain at least part of the ionophore mechanism of biological action of aza-crown ethers. 相似文献
58.
Andreeva Olga V. Garifullin Bulat F. Zarubaev Vladimir V. Slita Alexander V. Yesaulkova Iana L. Saifina Liliya F. Shulaeva Marina M. Belenok Maya G. Semenov Vyacheslav E. Kataev Vladimir E. 《Molecular diversity》2021,25(1):473-490
Molecular Diversity - Based on the fact that a search for influenza antivirals among nucleoside analogues has drawn very little attention of chemists, the present study reports the synthesis of a... 相似文献
59.
60.
Zoya Allambergenova Martyna Kasela Grzegorz Adamczuk Ewelina Humeniuk Magdalena Iwan ukasz
witek Anastazja Boguszewska Barbara Rajtar Aleksandra Jzefczyk Tomasz Baj Krzysztof Kamil Wojtanowski Dmitry Korulkin Kaldanay Kozhanova Liliya Ibragimova Zuriyadda Sakipova Katarzyna Tykiewicz Anna Malm Krystyna Skalicka-Wo
niak 《Molecules (Basel, Switzerland)》2022,27(11)
The composition of the ethanolic extract from the aerial parts of Crocus alatavicus Regel & Semen from southern Kazakhstan spontaneous flora was analyzed together with the determination of its antibacterial, antifungal, antiviral and anticancer activity. The phytochemical profile analysis by high-performance liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectrometry (HPLC/ESI-QTOF-MS) revealed the presence of multiple kaempferol derivatives. High-performance reverse-phase liquid chromatography combined with a photodiode-array detection (RP-HPLC/PDA) found that kaempferol 3-O-dihexoside and kaempferol 3-O-acyltetrahexoside accounted for 70.5% of the kaempferol derivatives. The minimum inhibitory concentration (MIC) values of the extract for all the tested reference microorganisms were high, reaching 10 mg/mL for yeasts and 20 mg/mL for bacteria. In contrast, antiviral activity was observed at 2 mg/mL, resulting in the inhibition of the HSV-1-induced cytopathic effect and the reduction in virus infectious titer by 1.96 log, as well as the viral load by 0.85 log. Among the tested prostate cancer cell lines, significant cytotoxic activity of the extract was noted only on the LNCaP cell line, with an IC50 value of 1.95 mg/mL. The LNCaP cell line treated with 2 mg/mL of the extract showed a noticeably reduced number of spindle-shaped cells with longer cellular projections, a significant increase in the peak corresponding to the population of apoptotic cells in the sub-G1 phase and a decreased intracellular glutathione (GSH) level, suggesting the prooxidative properties of the extract. The obtained data provide novel information about the flavonoids present in the aerial part of C. alatavicus and suggest its potential application as a source of the compounds active against HSV-1 and metastatic, androgen-sensitive prostate cancer. 相似文献