全文获取类型
收费全文 | 330篇 |
免费 | 28篇 |
国内免费 | 18篇 |
专业分类
化学 | 196篇 |
晶体学 | 1篇 |
综合类 | 3篇 |
物理学 | 5篇 |
综合类 | 171篇 |
出版年
2023年 | 3篇 |
2022年 | 11篇 |
2021年 | 24篇 |
2020年 | 9篇 |
2019年 | 7篇 |
2018年 | 8篇 |
2017年 | 9篇 |
2016年 | 15篇 |
2015年 | 12篇 |
2014年 | 11篇 |
2013年 | 13篇 |
2012年 | 14篇 |
2011年 | 23篇 |
2010年 | 5篇 |
2009年 | 15篇 |
2008年 | 16篇 |
2007年 | 21篇 |
2006年 | 19篇 |
2005年 | 22篇 |
2004年 | 16篇 |
2003年 | 13篇 |
2002年 | 19篇 |
2001年 | 10篇 |
2000年 | 11篇 |
1999年 | 11篇 |
1998年 | 3篇 |
1997年 | 6篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有376条查询结果,搜索用时 821 毫秒
171.
Duy‐Khiet Ho Xabier Murgia Chiara De Rossi Rebekka Christmann Antonio G. Hüfner de Mello Martins Marcus Koch Anastasia Andreas Jennifer Herrmann Rolf Müller Martin Empting Rolf W. Hartmann Didier Desmaele Brigitta Loretz Patrick Couvreur Claus‐Michael Lehr 《Angewandte Chemie (International ed. in English)》2020,59(26):10201-10201
172.
Jing Shao Liu‐Yin Fan Wei Zhang Chen‐Gang Guo Si Li Yu‐Quan Xu Cheng‐Xi Cao 《Electrophoresis》2010,31(20):3499-3507
The low‐concentration phenazine‐1‐carboxylic acid (PCA) (=0.3 mM) extracted from fermentation broth of Pseudomonas sp. M18 was selected to be purified with a newly facile free flow electrophoresis (FFE) device with gratis gravity. Three factors of pH value and concentration of background buffer, and the cooling circle of FFE device were investigated for the purification of PCA in the FFE device. It was found that the pH value and concentration of background buffer had mild influences on the separation of PCA whether with cooling circle or not. However, the cooling circle had a much greater impact on the separation of PCA. The controlling of the band zone of PCA in FFE chamber would be difficult if without cooling circle, while the controlling would become easy if with cooling circle. Under the optimal conditions (10 mM pH 5.5 phosphate as background buffer, 30 mM pH 5.5 phosphate buffer as electrode solution, 5.46 mL/min background flux, 10 min residence time of injected sample, and 500 V), PCA could be continuously prepared from its impurities with relative high purity. The flux of sample injection was 115 μL/min, viz. 7 mL sample throughput per hour, and the recovery was up to 85%. All of the experiments indicated that the FFE technique was a good alternative tool for the study on natural biological control agents. 相似文献
173.
Sushil Kumar Mishra Johan Sund Johan Åqvist Jaroslav Koča 《Journal of computational chemistry》2012,33(29):2340-2350
The linear interaction energy (LIE) method to compute binding free energies is applied to lectin‐monosaccharide complexes. Here, we calculate the binding free energies of monosaccharides to the Ralstonia solanacearum lectin (RSL) and the Pseudomonas aeruginosa lectin‐II (PA‐IIL). The standard LIE model performs very well for RSL, whereas the PA‐IIL system, where ligand binding involves two calcium ions, presents a major challenge. To overcome this, we explore a new variant of the LIE model, where ligand–metal ion interactions are scaled separately. This model also predicts the saccharide binding preference of PA‐IIL on mutation of the receptor, which may be useful for protein engineering of lectins. © 2012 Wiley Periodicals, Inc. 相似文献
174.
Nawong Boonnak Chatchanok Karalai Suchada Chantrapromma Hoong-Kun Fun Kan Chantrapromma 《Tetrahedron》2009,65(15):3003-3013
Cochinchinones I-L (1-3 and 13) along with 11 known xanthones (4-12, 14, and 15) were isolated from the resin and green fruits of Cratoxylum cochinchinense. In addition, four new acetylated compounds (16-19) were derivatized from 7-geranyloxy-1,3-dihydroxyxanthone (14) and 3-geranyloxy-1,7-dihydroxyxanthone (15). All compounds were characterized on the basis of spectroscopic analyses. The structures of cochinchinone I (1), a monoacetate (18) and a dibrosylate (20), were also confirmed by X-ray diffraction analysis. The antibacterial and antifungal activities of selected compounds were evaluated as well. 相似文献
175.
Combining Topology and Sequence Design for the Discovery of Potent Antimicrobial Peptide Dendrimers against Multidrug‐Resistant Pseudomonas aeruginosa 下载免费PDF全文
Michaela Stach Thissa N. Siriwardena Dr. Thilo Köhler Prof. Dr. Christian van Delden Priv.‐Doz. Dr. Tamis Darbre Prof. Dr. Jean‐Louis Reymond 《Angewandte Chemie (International ed. in English)》2014,53(47):12827-12831
Multidrug‐resistant opportunistic bacteria, such as Pseudomonas aeruginosa, represent a major public health threat. Antimicrobial peptides (AMPs) and related peptidomimetic systems offer an attractive opportunity to control these pathogens. AMP dendrimers (AMPDs) with high activity against multidrug‐resistant clinical isolates of P. aeruginosa and Acinetobacter baumannii were now identified by a systematic survey of the peptide sequences within the branches of a distinct type of third‐generation peptide dendrimers. Combined topology and peptide sequence design as illustrated here represents a new and general strategy to discover new antimicrobial agents to fight multidrug‐resistant bacterial pathogens. 相似文献
176.
Jing Song GU * Ping XU Yin Bo QU State Key Laboratory of Microbial Technology Shandong University Jinan The school of Chemistry Environmental Engineering Jinan University Jinan 《中国化学快报》2002,13(12)
Pyruvate has received increasing attention in recent years as a potential precursor for the synthesis of L-amino acids1. Compared with other small non-chiral building blocks, pyruvate is relatively expensive. Conventional processes for preparing pyruvate include a process comprising reacting sodium cyanide and acetyl chloride to synthesize acetyl cyanide and hydrolyzing the acetyl cyanide, and a process comprising reacting tartaric acid and potassium hydrogen sulfate. These processes not on… 相似文献
177.
固定化细胞生产黑色素的研究 总被引:8,自引:1,他引:7
利用固定化产酪氨酸酶的假单胞菌(Pseudomonassp.)以酪氨酸为底物生产黑色素.该黑色素的紫外扫描光谱图显示随波长的减小其吸收值增大,在210nm处有一吸收峰;红外光谱显示它在3μm和6μm处有吸收峰,从而证实它是一种黑色素.固定化细胞摇瓶半连续发酵产黑色素结果表明,最适温度为37℃,最适pH为9.5.加入微量铜离子、供氧良好和较低的底物加入量有利于黑色素的生成.在生理盐水中低温振荡处理可提高操作稳定性,使重复利用次数达到9次,连续使用180h 相似文献
178.
《Magnetic resonance in chemistry : MRC》2003,41(8):615-621
Pseudomonas putida strain KT2442, harbouring the pWW0 TOL plasmid, was grown with a number of different homologous aromatic acids as carbon sources. Small samples of liquid culture supernatant were collected and directly analysed by 2D NMR spectroscopy. In all cases similar compounds with olefinic signals were observed to accumulate. To elucidate the structures of these compounds, 2D NMR experiments with 500 and 600 MHz spectrometers equipped with a CryoProbe (Bruker BioSpin) were performed on samples obtained from a culture growing on 4‐methylbenzoate and, for 13C spectroscopy, on 13C‐labelled 4‐methylbenzoate. In all cases a 1,2‐dihydroxycyclohexa‐3,5‐diene‐carboxylate derivative was identified. The use of this technique helped us to identify easily some metabolites that were released into the solution by bacteria and to follow their secretion as a function of time. The high sensitivity of the present approach allowed a clear and rapid acquisition of spectra, notwithstanding the low concentration of the compounds. The benefits of introducing the use of NMR cryoprobes to perform metabolic pathway studies is demonstrated. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
179.
Fernando J. S. Oliveira Leonardo Vazquez Norberto P. De Campos Francisca P. de Fran?a 《Applied biochemistry and biotechnology》1996,131(1-3):727-737
Biosurfactants production by a strain of Pseudomonas aeruginosa using palm oil as a sole carbon source was investigated. The experiments were carried out in 500-mL conical flasks containing
100 mL of mineral media supplemented with palm oil as the sole carbon source. The P. aeruginosa FR strain was able to reduce surface tension of three tested inorganic media. Rotation velocities from 100 to 150 rpm provided
free-cell fermented media with the lowest surface tension of approx 33 mN/m. Emulsification index results of even 100% were
achieved when diesel was used as oil phase. Eight surface-active compounds produced by the bacterium were identified by mass
spectrometry. 相似文献
180.
从成都土壤中分离到一株假单胞菌,编号Hy—1。该菌株为革兰氏阴性需氧短杆菌,具极生丛鞭毛,营呼吸代谢,化能异养;还具有能分解Twccn60,液化明胶,不水解淀粉,产生聚—B—羟基丁酸盐颗粒(PHB)等特性。该菌株的代谢产物对一些革兰氏阳性细菌有较强拮抗作用。Hy—1菌苗对小白鼠多房棘球蚴移植泡块有显著抑制作用,能阻止多房棘球蚴在鼠体内的生长,发育和扩散。初步毒理试验发现Hy—1 对小鼠无急性毒性作用,在体内无存活扩散现象。 相似文献