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121.
Direct Electrochemical Sensing of Phenazine‐1‐carboxylic Acid Secreted by Pseudomonas chlororaphis subsp. aureofaciens BCRC 11057T Using Disposable Screen‐printed Carbon Electrode 下载免费PDF全文
Asif Hameed Hong‐Wei Pi Shih‐Yao Lin Wei‐An Lai Li‐Sen Young You‐Cheng Liu Fo‐Ting Shen Chiu‐Chung Young 《Electroanalysis》2016,28(4):846-853
A novel electrochemical approach for direct recognition of antibiotic phenazine‐1‐carboxylic acid (PCA) was developed. PCA was electropolymerized on preanodized screen‐printed carbon electrode (SPCE*‐PCA) through repetitive cyclic voltammetry and characterized by XPS and FESEM. Electron transfer involved intermediate phenomenon of diffusion‐controlled redox process and surface bound redox reaction. At pH 8 (optimum), SPCE*‐PCA had a detection limit of 0.51±0.04 μM, a quantification limit of 1.7±0.13 μM, linearity of up to 50 µM, a repeatability of 15.5 % and a reproducibility of 1.7 %. PCA secreted by Pseudomonas chlororaphis subsp. aureofaciens BCRC 11057T was investigated successfully using present single run approach. 相似文献
122.
LSD1-related proteins of Arabidopsis with LSDl-like zinc finger domains regulate disease resistance and programmed cell death (PCD). We cloned a rice OsLOL2 gene, orthologous to LSD1 of Arabidopsis and expressed it in a tobacco plant. Transgenic tobacco lines displayed enhanced disease resistance to a virulent bacterium Pseudomonas syringae pv. tabaci (Pst). RT-PCR analysis showed that overexpression of OsLOL2 in transgenic tobacco lines resulted in upregulation of two pathogenesis-related (PR) protein genes, PR2 and PR5. Our results suggest that overexpression of OsLOL2 in transgenic tobacco enhances the resistance through the induction of PR proteins and hypersensitive response-like reaction. 相似文献
123.
Lei Y Mulchandani P Chen W Mulchandani A 《Applied biochemistry and biotechnology》2007,136(3):243-250
A whole cell-based amperometric biosensor for highly selective, sensitive, rapid, and cost-effective determination of the
organophosphate pesticides fenitrothion and ethyl p-nitrophenol thiobenzenephosphonate (EPN) is discussed. The biosensor comprised genetically engineered p-nitrophenol (PNP)-degrading bacteria Pseudomonas putida JS444 anchoring and displaying organophosphorous hydrolase (OPH) on its cell surface as biological sensing element and carbon
paste electrode as the amperometric transducer. Surface-expressed OPH catalyzed the hydrolysis of organophosphorous pesticides
such as fenitrothion and EPN to release PNP and 3-methyl-4-nitrophenol, respectively, which were subsequently degraded by
the enzymatic machinery of P. putida JS444 through electrochemically active intermediates to the TCA cycle. The electrooxidization current of the intermediates
was measured and correlated to the concentration of organophosphates. Operating at optimum conditions, 0.086 mg dry wt of
cell operating at 600 mV of applied potential (vs Ag/AgCl reference) in 50 mM citratephosphate buffer, pH 7.5, with 50 μM CoCl2 at room temperature, the biosensor measured as low as 1.4 ppb of fenitrothion and 1.6 ppb of EPN. There was no interference
from phenolic compounds, carbamate pesticides, triazine herbicides, or organophosphate pesticides without nitrophenyl substituent.
The service life of the biosensor and the applicability to lake water were also demonstrated. 相似文献
124.
In this study,the protective effects of Cimicifugae Rhizoma(CR) was demonstrated in Pseudomonas aeruginosa-induced pneumonia mouse model.To identify the anti-inflammatory ingredients,an ultraperformance liquid chromatography quadrupole time-of-flight mass spectrometry(UPLC/Q-TOF-MS)integrated nuclear factor κB(NF-κB) luciferase reporter assay screening system was carried out.As a result,some caffeic acid derivatives,including caffeic acid,ferulic acid/isoferulic acid,fukinolic acid,and cimicifugic acid ingredients were identified as the potential effective compounds from CR.For testing the anti-inflammatory capacity,caffeic acid was demonstrated to inhibit NF-kB and reduce the levels of IL-6 and IL-8 in TNF-α-treated BEAS-2B cells in a dose-dependent manner.Hence,CR preparations and its cinnamic acid derivatives have the possibility to be developed as a complementary therapy in the treatment of respiratory system infection in clinics. 相似文献
125.
Bacterial quorum-sensing regulatory systems can be summarized in a simple model wherein an autoinducer molecule accumulates
in cultures and stimulates regulatory changes in gene expression upon reaching a critical threshold concentration. Although
quorum sensing was originally thought to be an isolated phenomenon governing the regulation of a handful of processes in only
a few bacteria, it is now considered to be a widespread mechanism for coordinating bacterial gene expression. Over decades
of research, investigations of autoinducer-mediated regulation have revealed that these systems are far more complicated than
originally appreciated, and such discoveries have accelerated recently with the application of molecular and genomic tools.
The focus of this review is to highlight recent advances describing complexities that go beyond the simple model of quorum
sensing. These complexities include the regulation of autoinducer production and degradation, the presence of multiple quorum-sensing
systems in individual bacteria that regulate diverse genes, often in coordination with other regulatory elements, and the
influence of interorganismal interactions on quorum sensing. 相似文献
126.
采用固定化洋葱假单胞菌脂肪酶(Pseudomonas cepacia lipase,PC脂肪酶)为催化剂,在有机溶剂体系中研究了环己烷二甲醇和环己烷二甲酸对聚丁二酸丁二醇酯(PBS)的改性共聚物,即聚(丁二酸丁二醇-co-丁二酸环己烷二甲醇酯)(PBS-co-CHDMS)和聚(丁二酸丁二醇-co-环己烷二甲酸丁二醇酯)(PBS-co-BCHDA)的降解规律及其差异性.通过共聚物降解率随时间的变化、降解产物的MALDI-TOF-MS分析研究了共聚物降解规律,并以分子模拟分别研究了降解差异性和PC脂肪酶与底物的结合机制.研究结果表明,PC脂肪酶均可催化PBS基共聚物降解;在降解60 h后,相比较于PBS-co-BCHDA,PBS-co-CHDMS降解率均更大;其中PBS-co-10%CHDMS降解率最大,为85%.共聚物降解不仅生成了线型小分子,还产生了部分环状低聚物;此外,PBS-co-CHDMS降解产生的低聚物种类比PBS-co-BCHDA的要多.分子对接模拟结果表明,在氯仿中,PC脂肪酶与底物结合自由能的大小顺序为CMSCMBSCMBCABBSB,即含有丁二酸环己烷二甲醇酯(CHDMS)单元的底物与PC脂肪酶活性位点的对接更为稳定. 相似文献
127.
P. Sankar Ganesh 《Natural product research》2015,29(24):2295-2298
The antibiofilm activity of Murraya koenigii essential oil (EO) against Pseudomonas aeruginosa PAO1 was investigated in this study. A decrease in the production of rhamnolipid, extracellular polymeric substance and swarming motility was observed by the EO treatment (0.3% v/v). The static microtitre plate assay revealed 80% reduction in biofilm formation by P. aeruginosa PAO1 on M. koenigii EO treatment. Fluorescence microscopy and scanning electron microscopy analyses confirmed the reduction of biofilm formation in P. aeruginosa PAO1 when treated with M. koenigii EO. Gas chromatography–mass spectrometry analysis of the EO revealed the presence of well-known antibiofilm agents such as spathulenol (5.85%), cinnamaldehyde (0.37%) and linalool (0.04%). Cinnamaldehyde has not been previously reported in M. koenigii EO. The potent antibiofilm properties of M. koenigii EO may be effectively exploited in food and pharmaceutical industries as well as in controlling Pseudomonas biofilms on indwelling medical devices. 相似文献
128.
Xinyu Zheng Qiao Cao Qin Cao Fei Mao Xiaokang Li Jin Zhu Lefu Lan Jian Li 《中国化学快报》2020,31(2):413-417
Polymyxin B(PB),as the last-line of defense against multidrug-resistant Gram-negative bacteria,has caused resistance to P.aeruginosa recently.Fortunately,synergistic treatment could preserve the last class of antibiotics and reduce the emergency of drug resistance.Here,we performed a screen of 970 approved drugs synergized with PB against the P.aeruginosa DK2,which is severely resistant to PB,MIC=512μg/mL.Encouragingly,we found fluoroquinolones could synergy with PB and achieved an obvious reduction in MIC of PB below the clinical susceptible breakpoint(2 μg/mL).Especially,gemifloxacin achieved the highest synergistic effect with PB,leading to a 4096-fold MIC reduction(reduced from512 μg/mL to 0.125 μg/mL).Furthermore,synergistic effect was also observed in the combination of gemifloxacin and colistin.Finally,outer membrane permeabilization assay showed that gemifloxacin could increase the permeability of bacterial cell membranes for P.aeruginosa which partly explained the synergy mechanism.These results indicate that fluoroquinolones represent attractive synergists to address the emerging threat of polymyxin-resistant infections. 相似文献
129.
G. Richard Stephenson Christopher E. AnsonGraham J. Swinson 《Tetrahedron letters》2011,52(28):3547-3550
The endo face selectivity of the complexation of the biologically derived 3-phenyl-1,2-dihydroxycyclohexa-3,5-diene ligand has been proved by an X-ray crystallographic study of the enantiopure (1R,2S,3S) η4 tricarbonyliron complex, and the correlation between the absolute configuration of the complex and its circular dichroism curve has been established to provide a basis on which to assign absolute configurations in the synthetically important [‘-(Ar)CCH-CHCH-’]Fe(CO)3 series. 相似文献
130.
W1-2 菌株是以好氧活性污泥为菌源, 以四溴双酚 A(tetrabromobisphenol A, TBBPA)驯化筛选得到的一株新型好氧降解菌株. 16S rDNA 序列表明, W1-2 菌株属于假单胞菌属(Pseudomonas sp.), 主要以酶降解的模式去除 TBBPA. 在 30 ℃、pH=7、 150 r/min 和无其他碳源辅助的条件下, W1-2 菌株对 10 mg/L TBBPA 5 d 的好氧降解率可达 91.4%. 温度、转速、pH 值及 TBBPA 的质量浓度均会影响 W1-2 菌株的降解特性, 其中 pH 值对降解率的影响最大. W1-2 菌株最适宜降解和生长的环境条件为 150 r/min、30~ 35 ℃, TBBPA 质量浓度为 10 mg/L 和 pH=8. 此外, W1-2 菌株也是为数不多的无需其他碳源支持、能在高 TBBPA 质量浓度(30 mg/L)和低氧(0 r/min)条件下仍保持高降解能力的好氧降解菌株. 对 W1-2 菌株的研究, 为探究好氧环境下能降解 TBBPA 的微生物的修复提供了新的视角. 相似文献