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71.
微柱高效液相色谱法测定大鼠脑微透析液中 的乙酰胆碱和胆碱 总被引:2,自引:0,他引:2
用所建立的微柱高效液相色谱分离、柱后固定化酶反应器酶解、电化学检测器检测的方法,
对用不同浓度异氟醚麻醉前后的大鼠脑微透析液中的乙酰胆碱和胆碱的浓度进行了测定。在
乙酰胆碱和胆碱的浓度为10~ 2 000 nmol/L 时,其浓度分别与各自相应峰高的线性
关系良好,两者的检测限(以信噪比为3计)均可达5 nmol/L 。微透析液中乙酰胆碱和胆碱的含量在大鼠清醒时最高,随着异氟醚吸入浓度的增加,乙酰胆碱和胆碱含量明显降低。在大鼠海马和脑皮层中乙酰胆碱浓度的降低与大鼠吸入异氟醚的浓度相关( P < 相似文献
72.
Shlomo Margel Ella Cohen Yehudit Dolitzky Orit Sivan 《Journal of polymer science. Part A, Polymer chemistry》1992,30(6):1103-1110
The synthesis and characterization of novel surfaces composed of polyacrolein microspheres covalently bonded onto polyethylene films are described. These surfaces were prepared through a sequence of reactions carried out onto polyethylene films in order to form primary amine groups at the w position. Polyacrolein microspheres in water were then covalently bonded to these modified polyethylene surfaces. The binding between the microspheres and the modified surfaces is due to the interaction between the aldehyde groups of the microspheres and the amine groups of the modified surfaces to form the polyvalent Schiff base bonds. Fourier transform-infrared/attenuated total reflection, electron spectroscopy for chemical analysis, contact angle measurements, and scanning electron microscopy have been used for the characterization of the modified polyethylene surfaces. 相似文献
73.
选择海藻酸钙和聚乙烯醇凝胶为固定化载体包埋假单胞菌(Pseudomonassp.),以提高该菌以L-酪氨酸为底物生产L-多巴的效率.海藻酸钙和聚乙烯醇固定的假单胞菌分别将发酵周期缩短了8和14h.半连续发酵的结果表明,海藻酸钙和聚乙烯醇固定化细胞分别能重复使用5次和14次,L-多巴生产效率比游离细胞分别提高了16%和160%.聚乙烯醇固定化细胞经过热处理和在生理盐水中振荡处理可明显提高L-多巴的生产效率和产量,过高的底物加入量不利于固定化细胞的重复使用 相似文献
74.
Pratap Singh 《Applied biochemistry and biotechnology》1984,9(2):161-172
PstI has been immobilized in agarose. A solution of low melting agarose containing 1,6-hexamethylenediamine and PstI formed
a gel that was effective in the linearization of pBR322 DNA. The gel containing PstI could be treated with 1,5-bis(N-acetylamino-N-succinimidoxy carbonyl)pentane, a crosslinking agent, without affecting the enzyme activity. Polymerization of acrylamide
in presence of PstI led to conisderably reduced enzyme activity, although EcoRI under identical conditions showed high activity.
It was found that acetylation of amino groups in PstI, by reaction with hydroxysuccinimide acetate, led to total inactivation
of the enzyme activity. This reaction showed the presence of reactive amino groups that were essential for the enzyme activity
of PstI. Involvement of these amino groups in binding to activated Sepharose 4B, during covalent immobilization, was responsible
for inactive enzyme preparations. 相似文献
75.
An immobilized microbial heparinase for blood deheparinization 总被引:6,自引:0,他引:6
R. J. Linhardt C. L. Cooney D. Tapper C. A. Zannetos A. K. Larsen R. Langer 《Applied biochemistry and biotechnology》1984,9(1):41-55
A new medical application of an immobilized microbial enzyme is described. Extracorporeal devices require systemic heparin
administration to prevent thrombus formation; however, the use of heparin often leads to serious hemorrhagic complica tions.
Heparinase isolated from Flavobacterium has been immobilized and used in a fluidized bed reactor to eliminate heparin from
blood passing through an extracorporeal circuit both in vitro and in vivo. This paper discusses the stepwise de velopment
of this heparinase reactor including: (1) improvements in the fermentation resulting in an inexpensive large-scale source
of heparinase without the addition of the previously required inducer, heparin; (2) the use of batch processes to adapt previous
purification schemes to large-scale heparinase production and the subsequent purifica tion of heparinase to a single SDS-PAGE
banding protein; (3) the immobilization of heparinase with a 91% activity recovery and good stability, (4) the design and
suc cessful testing of a fluidized bed reactor containing immobilized heparinase in the re moval of clinically used quantities
of heparin from both human blood in vitro and ca nine blood in vivo; and (5) the initiation of animal studies focusing on
the toxicology of heparinase-derived heparin degradation products and the short and long term effects of exposure to these
products and to heparinase. 相似文献
76.
M. J. T. Carrondo J. P. S. G. Crespo M. J. Moura 《Applied biochemistry and biotechnology》1988,17(1-3):295-312
The kinetics ofP. acidipropionici (ATCC25562), a xylose-utilizing rumen microorganism, was studied to assess its use for propionic acid production from wood
hydrolyzates.
Propionic acid has been shown to have a stronger inhibitory effect than acetic acid, with the undissociated acid form being
responsible for the majority of the inhibitory effect. Thus, in batch tests with pH controlled at 6.0, the propionic acid
concentration reaches 25 g/L and the acetic acid 7 g/L. Xylose uptake rate is dependent on the specific growth rate and glucose
concentration.
An immobilized cell columnar reactor at very high product yields (80%) proved adequate for propionic production. At cell concentrations
of 95 g/L with high product concentration, volumetric productivities of 2.7 g/L·h were obtained in ultrafiltration cell recycle
systems. 相似文献
77.
78.
采用点击化学的方法将自然界中的天冬氨酸(aspartic acid)键合到硅球上(命名为Click Asp),并将Fe3+配位到Click Asp上,合成固定金属离子亲和色谱(IMAC)材料(Fe3+-Click Asp);采用红外光谱、X射线电子能谱和扫描电镜等表征证明Fe3+-Click Asp成功合成。将此IMAC材料用于蛋白质酶解液和牛奶中的磷酸化肽的富集,实现了磷酸化肽的高选择性富集。本研究为磷酸化蛋白质组学提供了新材料和新方法。 相似文献
79.
Rafael Doležal Natálie Karásková Karel Musil Martin Novák Nadezhda V. Maltsevskaya Dávid Maliňák 《Analytical letters》2018,51(15):2401-2414
The biological activity of drugs on organisms is associated with the pharmacokinetic properties, such as the ability to penetrate through environments of varying polarity such as cellular organelles. In this area, particular attention is turned to the physicochemical properties that determine the potential of drugs to pass across the blood–brain barrier and thus to act on the central nervous system. In this study, special effort has been devoted to the simulation of passive diffusion of seven drugs (propranolol, ibuprofen, atenolol, promazine, chlorpromazine, imipramine, and desipramine) through the blood–brain barrier by high-performance liquid chromatography (HPLC) using a column with an immobilized artificial membrane. Gradient reverse elution was used to develop a linear correlation model for the capacity factors kIAM and the in vivo logarithmic values of brain-to-blood drug concentration ratios (log BB) with R of 0.9851. Eleven additional pharmaceuticals were determined by the same method to predict their potential to penetrate the blood–brain barrier. The reported analytical method represents an alternative tool for rapid and noninvasive assessment of the absorption properties of chemicals, especially for the development of novel drugs. The retention of the studied compounds on the immobilized artificial membrane column was also compared with three other C18-based stationary phases. Herein, the results of the HPLC determination of drugs using an immobilized artificial membrane are briefly discussed with respect to a general application of the method for evaluating a broader spectrum of pharmaceutical compounds. 相似文献
80.
《中国化学会会志》2018,65(8):960-969
In the present study, Fe2+ and Ni2+ immobilized on hydroxyapatite‐core‐shell γ‐Fe2O3 (γ‐Fe2O3@HAp‐Fe2+ and γ‐Fe2O3@HAp‐Ni2+) with a high surface area has been synthesized and characterized by Fourier transform infrared (FTIR), X‐ray diffraction (XRD), vibrating sample magnetometer (VSM), transmission electron microscopy (TEM), and scanning electron microscope (SEM) techniques. Then, γ‐Fe2O3@HAp‐Fe2+ and γ‐Fe2O3@HAp‐Ni2+ were used as a new and magnetically recoverable nano catalyst for the selective oxidation of sulfides to sulfoxides with 33% aqueous H2O2 (0.5 mL) as an oxidant at room temperature in good to excellent yields and short reaction time. Nontoxicity of reagent, mild reaction condition, inexpensive and high catalytic activity, simple experimental procedure, short period of conversion and excellent yields, and ease of recovery from the reaction mixture using an external magnet are the advantages of the present method. 相似文献