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181.
Ahmad Tahir Ali Sher Shah Syed Bilal Hussian Khan Inam Ullah Hassan Muhammad Abul Ullah Syed Irfan 《Cluster computing》2022,25(4):2403-2415
Cluster Computing - The device-to-device D-2-D Communication empowered Cloud Radio Access Network (CRAN) which is examined to be auspicious system model, gives energy efficiency and high data rate.... 相似文献
182.
Khan Haroon Labanca Fabiana Ullah Hammad Hussain Yaseen Tzvetkov Nikolay T. Akkol Esra Küpeli Milella Luigi 《Phytochemistry Reviews》2022,21(2):385-400
Phytochemistry Reviews - Over the years, the attention towards the role of phytochemicals in dietary natural products in reducing the risk of developing cancer is rising. Cancer is the second... 相似文献
183.
The aim of this study was to increase the stability and water solubility of fragrance materials, to provide controlled release of these compounds, and to convert these substances from liquid to powder form by preparing their inclusion complexes with cyclodextrins (CDs). For this purpose, linalool and benzyl acetate were chosen as the fragrance materials. The use of beta-cyclodextrin (beta CD) and 2-hydroxypropyl-beta-cyclodextrin (2-HP beta CD) for increasing the solubility of these 2 fragrance materials was studied. Linalool and benzyl acetate gave a B-type diagram with beta CD, whereas they gave an A(L)-type diagram with 2-HP beta CD. Therefore, complexes of fragrance materials with 2-HP beta CD at 1:1 and 1:2 molar ratios (guest:host) were prepared. The formation of inclusion complexes was confirmed using proton nuclear magnetic resonance ((1)H-NMR) spectroscopy and circular dichroism spectroscopy. The results of the solubility studies showed that preparing the inclusion complex with 2-HP beta CD at a 1:1 molar ratio increased the solubility of linalool 5.9-fold and that of benzyl acetate 4.2-fold, whereas the complexes at a 1:2 molar ratio increased the solubility 6.4- and 4.5-fold for linalool and benzyl acetate, respectively. The stability and in vitro release studies were performed on the gel formulations prepared using uncomplexed fragrance materials or inclusion complexes of fragrance materials at a 1:1 molar ratio. It was observed that the volatility of both fragrance materials was decreased by preparing the inclusion complexes with 2-HP beta CD. Also, in vitro release data indicated that controlled release of fragrances could be possible if inclusion complexes were prepared. 相似文献
184.
Riaz N Nawaz SA Mukhtar N Malik A Afza N Ali S Ullah S Muhammad P Choudhary MI 《化学与生物多样性》2007,4(1):72-83
Bractin A (=(2S,3S,4R,5E)-2-{[(2R)-2-hydroxydodecanoyl]amino}triacont-5-ene-1,3,4-triol; 1) and bractin B (=(2S,3S,4R,5E,8E)-2-{[(2R)-2-hydroxyhexacosanoyl]amino}pentadeca-5,8-diene-3,4,15-triol 1-O-beta-D-glucopyranoside; 2), new sphingolipids, and bractic acid (=(5Z,10Z,15Z)-2-decyl-4,7,8,12,13,17,18-heptahydroxy-20,23-dioxopentacosa-5,10,15-trienoic acid; 3), a long-chain polyhydroxy acid, were isolated from the whole plant Ajuga bracteosa along with four known diterpenoids 4-7. Their structures were deduced by spectral studies including 1D- and 2D-NMR spectroscopy. Compounds 1-3 displayed inhibitory potential against enzyme lipoxygenase, while compounds 4-7 inhibited cholinesterase enzymes in a concentration-dependent manner with IC(50) values in the range 10.0-33.0, 14.0-35.2, and 10.0-19.0 microM for lipoxygenase, acetylcholinesterase, and butyrylcholinesterase, respectively. Lineweaver-Burk, and Dixon plots, and their secondary replots indicated that all compounds exhibit non-competitive type of inhibition with K(i) values in the range of 9.5-35.2, 15.2-36.0, and 11.6-20.5 microM, for lipoxygenase, acetylcholinesterase, and butyrylcholinesterase, respectively. 相似文献
185.
Zafar Iqbal Khan Kafeel Ahmad Iqra Ashraf Sumaira Gondal Muhammad Sher Zafar Hayat Vito Laudadio Vincenzo Tufarelli 《Saudi Journal of Biological Sciences》2015,22(3):249-255
The present study aimed to evaluate the bioaccumulation of some macrominerals in grazing buffaloes fed forage irrigated with sewage water or canal water. In particular, the transfer of sodium (Na), magnesium (Mg), potassium (K) and calcium (Ca) from soil to plant and in turn to animals was evaluated under sub-tropical environmental conditions. Samples of soil, forage and buffalo hair were collected and digested by wet method. Sodium and K concentrations were significantly higher in the soil but lower in the forages; however, Mg and Ca concentrations in both soil and forages were higher. The correlation between soil, forage and hair showed an imbalanced flow of Na, Mg and K and a balanced flow of Ca from soil to forage and then to animals. Based on the findings, the highest rates of transfer of minerals were found for sewage water treatment, whereas lowest rates were found for canal water treatment, except for Na. As the transfer of minerals depends on their bioavailability, the highest values may be due to the high rates of mineral uptake by plants. Thus, the high transfer rate of some elements by plants could become toxic in future causing detrimental effect to grazing livestock. 相似文献
186.
Horia Vais J. Kevin Foskett Ghanim Ullah John E. Pearson Don-On Daniel Mak 《The Journal of general physiology》2012,140(6):697-716
The ubiquitous inositol 1,4,5-trisphosphate (InsP3) receptor
(InsP3R) Ca2+ release channel plays a central
role in the generation and modulation of intracellular Ca2+
signals, and is intricately regulated by multiple mechanisms including
cytoplasmic ligand (InsP3, free Ca2+, free
ATP4−) binding, posttranslational modifications, and
interactions with cytoplasmic and endoplasmic reticulum (ER) luminal proteins.
However, regulation of InsP3R channel activity by free
Ca2+ in the ER lumen
([Ca2+]ER) remains poorly understood because of
limitations of Ca2+ flux measurements and imaging techniques.
Here, we used nuclear patch-clamp experiments in excised luminal-side-out
configuration with perfusion solution exchange to study the effects of
[Ca2+]ER on homotetrameric rat type 3
InsP3R channel activity. In optimal
[Ca2+]i and subsaturating [InsP3],
jumps of [Ca2+]ER from 70 nM to 300 µM
reduced channel activity significantly. This inhibition was abrogated by
saturating InsP3 but restored when
[Ca2+]ER was raised to 1.1 mM. In suboptimal
[Ca2+]i, jumps of
[Ca2+]ER (70 nM to 300 µM) enhanced
channel activity. Thus, [Ca2+]ER effects on channel
activity exhibited a biphasic dependence on
[Ca2+]i. In addition, the effect of high
[Ca2+]ER was attenuated when a voltage was
applied to oppose Ca2+ flux through the channel. These
observations can be accounted for by Ca2+ flux driven through
the open InsP3R channel by [Ca2+]ER,
raising local [Ca2+]i around the channel to
regulate its activity through its cytoplasmic regulatory
Ca2+-binding sites. Importantly,
[Ca2+]ER regulation of InsP3R
channel activity depended on cytoplasmic Ca2+-buffering
conditions: it was more pronounced when [Ca2+]i was
weakly buffered but completely abolished in strong
Ca2+-buffering conditions. With strong cytoplasmic buffering
and Ca2+ flux sufficiently reduced by applied voltage, both
activation and inhibition of InsP3R channel gating by physiological
levels of [Ca2+]ER were completely abolished.
Collectively, these results rule out Ca2+ regulation of
channel activity by direct binding to the luminal aspect of the channel. 相似文献
187.
The inositol 1,4,5-trisphosphate (IP(3)) receptor (IP(3)R) channel is crucial for the generation and modulation of intracellular Ca(2+) signals in animal cells. To gain insight into the complicated ligand regulation of this ubiquitous channel, we constructed a simple quantitative continuous-time Markov-chain model from the data. Our model accounts for most experimentally observed gating behaviors of single native IP(3)R channels from insect Sf9 cells. Ligand (Ca(2+) and IP(3)) dependencies of channel activity established six main ligand-bound channel complexes, where a complex consists of one or more states with the same ligand stoichiometry and open or closed conformation. Channel gating in three distinct modes added one complex and indicated that three complexes gate in multiple modes. This also restricted the connectivity between channel complexes. Finally, latencies of channel responses to abrupt ligand concentration changes defined a model with specific network topology between 9 closed and 3 open states. The model with 28 parameters can closely reproduce the equilibrium gating statistics for all three gating modes over a broad range of ligand concentrations. It also captures the major features of channel response latency distributions. The model can generate falsifiable predictions of IP(3)R channel gating behaviors and provide insights to both guide future experiment development and improve IP(3)R channel gating analysis. Maximum likelihood estimates of the model parameters and of the parameters in the De Young-Keizer model yield strong statistical evidence in favor of our model. Our method is simple and easily applicable to the dynamics of other ion channels and molecules. 相似文献
188.
Mustafa G Khan IU Ashraf M Afzal I Shahzad SA Shafiq M 《Bioorganic & medicinal chemistry》2012,20(8):2535-2539
The present study describes a convenient method for the synthesis of new lipoxygenase inhibitors, 4-(toluene-4-sulfonylamino)-benzoic acids from p-amino benzoic acid. Reaction of p-amino benzoic acid with p-toluenesulfonyl chloride provided thirteen N- and O-alkylation products 4a-4m in moderate to good yields. Lipoxygenase inhibition of newly formed sulfonamide derivatives was investigated and some of these compounds 4m, 4g, 4e, 4f and 4j showed good lipoxygenase inhibitory activities with IC(50) values ranged between 15.8 ± 0.57 and 91.7 ± 0.61 μmol whilst all other compounds exhibited mild anti-lipoxygenase activities with IC(50) values ranged between 139.2 ± 0.75 and 232.1 ± 0.78 μmol. N-alkylated products were more active against the enzyme than O-alkylated or both N- and O-alkylated ones. All synthesized sulfonamides were recrystallized in chloroform to give these title compounds which were characterized using FTIR, (1)H NMR, (13)C NMR, elemental analysis and single crystal X-ray diffraction techniques. 相似文献
189.
A series of novel N,N-dimethyl-N'-(5-(Ar-sulfonamido) benzo[d]isothiazol-3-yl)formimidamides was designed and synthesized as 5-HT(6) ligands. Here N,N-dimethyl formimidamides was used as a replacement for an aminoethyl moiety. In vitro functional assays demonstrated compounds 9b and 9i significantly inhibited the 5-HT-induced Ca(2+) increases (9b; IC(50)=0.36 μM and 9i; IC(50)=0.44 μM), indicating that 9b and 9i were potent 5-HT(6) receptor antagonists. Compounds 9i also showed good selectivity on the 5-HT(6) over 5-HT(4) and 5-HT(7) receptors. 相似文献
190.
Azmat Ullah Rick Orij Stanley Brul Gertien J. Smits 《Applied and environmental microbiology》2012,78(23):8377-8387
Weak organic acids are naturally occurring compounds that are commercially used as preservatives in the food and beverage industries. They extend the shelf life of food products by inhibiting microbial growth. There are a number of theories that explain the antifungal properties of these weak acids, but the exact mechanism is still unknown. We set out to quantitatively determine the contributions of various mechanisms of antifungal activity of these weak acids, as well as the mechanisms that yeast uses to counteract their effects. We analyzed the effects of four weak organic acids differing in lipophilicity (sorbic, benzoic, propionic, and acetic acids) on growth and intracellular pH (pHi) in Saccharomyces cerevisiae. Although lipophilicity of the acids correlated with the rate of acidification of the cytosol, our data confirmed that not initial acidification, but rather the cell''s ability to restore pHi, was a determinant for growth inhibition. This pHi recovery in turn depended on the nature of the organic anion. We identified long-term acidification as the major cause of growth inhibition under acetic acid stress. Restoration of pHi, and consequently growth rate, in the presence of this weak acid required the full activity of the plasma membrane ATPase Pma1p. Surprisingly, the proposed anion export pump Pdr12p was shown to play an important role in the ability of yeast cells to restore the pHi upon lipophilic (sorbic and benzoic) acid stress, probably through a charge interaction of anion and proton transport. 相似文献