首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   465篇
  免费   18篇
儿科学   1篇
基础医学   55篇
口腔科学   70篇
临床医学   25篇
内科学   36篇
皮肤病学   1篇
神经病学   2篇
特种医学   8篇
外科学   56篇
综合类   33篇
预防医学   33篇
药学   142篇
中国医学   18篇
肿瘤学   3篇
  2023年   4篇
  2022年   6篇
  2021年   28篇
  2020年   15篇
  2019年   7篇
  2018年   12篇
  2017年   9篇
  2016年   8篇
  2015年   5篇
  2014年   17篇
  2013年   23篇
  2012年   16篇
  2011年   21篇
  2010年   9篇
  2009年   24篇
  2008年   20篇
  2007年   16篇
  2006年   21篇
  2005年   21篇
  2004年   21篇
  2003年   14篇
  2002年   23篇
  2001年   18篇
  2000年   12篇
  1999年   14篇
  1998年   10篇
  1997年   16篇
  1996年   12篇
  1995年   11篇
  1994年   3篇
  1993年   1篇
  1992年   6篇
  1991年   5篇
  1990年   5篇
  1989年   3篇
  1988年   2篇
  1987年   1篇
  1986年   3篇
  1985年   3篇
  1984年   3篇
  1983年   2篇
  1982年   1篇
  1981年   3篇
  1980年   1篇
  1979年   2篇
  1977年   1篇
  1975年   1篇
  1974年   1篇
  1973年   2篇
  1971年   1篇
排序方式: 共有483条查询结果,搜索用时 296 毫秒
1.
Abstract: The adsorptive characteristics of 5 dialysis membranes for recombinant human erythropoietin (EPO) were studied in vitro in a closed circuit system. For 120 min, EPO added with bovine serum was significantly adsorbed by polymethylmetacrylate (PMMA) and polyacry–lonitrile (PAN) membranes but not by Cuprophan, ethylene vinyl alcohol (EVAL), or polysulfone (PS) membranes. In addition the EPO adsorptive rate, as well as that of β2–microglobulin (β2–MG), was greater with a PMMA membrane than with a PAN membrane. EPO was not detected in the ultrafiltrate at 15 min with 5 membranes. These results indicate that EPO was eliminated by membrane adsorption only with some dialysis membranes.  相似文献   
2.
The effects of various metal cations and pH on the adsorption of uranium(VI) on strongly acidic cation exchanger Amberlite IR-118H (AIR-118H) were studied. The metal cations suppress U(VI) adsorption differently depending on their ionic radii. Adsorption of U(VI) on AIR-118H peaks at pH 3.4, which was attributed to the occurrence of different forms of U(VI) at different pH values. The adsorption data were then processed using the Frumkin–Fowler–Guggenheim equation, and the standard free energy of adsorption was calculated.  相似文献   
3.
To observe the effect of Gardenia extract ZG on the adsorption quantity of herpes simplex virus type 1 (HSV-1) so as to explore the mechanism of its antiviral activity, fluorescein isothiocyanate (FITC) was used as the fluorescent probe to label viruses and heparin sodium was used as control. Meanwhile , the effect of Gardenia extract ZG on the adsorption quantity on the surface of Hep-2 cells was determined by flow cytometry. It was demonstrated that adsorption of HSV-1 on the surface of Hep-2 cells exhibited the character of saturation and specificity and heparin sodium could prevent attachment of viruses on these cells. These results are in accord with those reported previously. It was also proved that the manner of drug-use prior to adsorption or simultaneous use of drug and adsorption was better than adsorption prior to drug-use, and the inhibition rates of the former and latter manner were 84. 76% and 82.92% respectively. Three manners of drug-use with Gardenia extract ZG were all effective to reduce the adsorption quantity of viruses, especially the manner of simultaneous use of drug and adsorption with an adsorption inhibition rate of 68.46% . From the above observation, it is apparent that the mechanism of anti-viral activity of Gardenia extract ZG may be via several steps involved in the HSV-1 adsorption.  相似文献   
4.
研究了磺化聚醚砜吸附柱对血浆中亚甲蓝的吸附效果,并检测了流经吸附柱的牛血清白蛋白随时间变化的规律以及过柱前后血浆中主要生化指标的变化情况.结果:磺化聚醚砜对亚甲蓝的吸附效果明显优于聚醚砜对亚甲蓝的吸附效果;其对白蛋白的吸附较小;对血浆中主要生化指标的影响可以忽略不计.  相似文献   
5.
本文采用放射性同位素标记的方法研究了嵌段聚醚型聚氨酯在纯纤维蛋白原溶液中和稀释血浆中的表面纤维蛋白原吸附性规律,考察了聚醚型聚氨酯的特性粘数及溶液体系中的NaCl浓度对材料表面纤维蛋白原吸附性的影响,结果表明,随着聚合物特性粘数的增大,材料表面的纤维蛋白原吸附量呈降低的趋势;溶液体系中盐浓度的降低导致纤维蛋白原凝固性增强,在纯纤维蛋白原溶液中,材料表面纤维蛋白原的吸附量相应增多,而在稀释血浆中,纤维蛋白原的吸附量相应减少,在达到最低值后又有上升的趋向,表明纤维蛋白原在材料表面的吸附还受血浆中其它大分子的影响。  相似文献   
6.
Summary Magnesium (Mg) is a conspicuous constituent of hard tissues but its possible role in biomineralization is poorly understood. It is possible that Mg2+ adsorbed onto bioapatites may contribute to the modulation of crystal growth as such inhibitory activity has been reported for synthetic apatites. The present study was undertaken to determine the adsorption isotherms of Mg ions onto synthetic apatites and biominerals in tooth and bone tissues in the presence of other ions of natural occurrence. Synthetic crystals used as adsorbents were hydroxyapatite and, as a better prototype for the biomineral, Mg-containing carbonatoapatite. Human enamel and dentin materials were obtained from extracted, caries-free, permanent teeth. Porcine dentin materials at two developmental stages were obtained from erupted deciduous and unerupted permanent teeth of a 6-month-old slaughtered piglet. Porcine bone was obtained from the cortical portion of the mandible of the same animal. All biomineral samples were pulverized and then treated by plasma ashing (deproteination) at about 60°C. Each of the powdered samples was equilibrated in solutions containing various initial concentrations of Mg2+, Ca2+, and Na+ (or K+) as nitrate salts. Following equilibration, concentrations (and activities) of magnesium and calcium ions in the experimental solution were determined. The pH values of the equilibrium solutions were in the range of 6.2–6.5. Experimental data of the Mg adsorption onto hydroxyapatite were interpreted on the basis of a Langmuir-type model for binary systems assuming competition of Mg2+ and Ca2+ for the same adsorption sites on the crystal surfaces of the apatites. According to this model, the adsorbed Mg is expressed as a function of the ionic activity ratio (Mg2+)/(Ca2+) in the equilibrium solution. The model contains two parameters, the adsorption selectivity constant Ks and the maximum number of adsorption sites N (mol/g). The numerical values of Ks were similar for all adsorbents used (synthetic and biological) and indicated the preferential adsorption of Ca2+ probably due to spacial restrictions extending to the very surface of the crystals. The initial level of Mg2+ in the surface pool was different in the various biominerals, probably reflecting the composition of fluid in which the biominerals were formed. Whereas the surface pool of Mg of human enamel was marginal, only 5% of the total Mg, significant fractions of the total Mg in human and porcine dentins (about 20–30%), and porcine bone (about 40%) existed on the crystal surfaces. There were significant differences in the total Mg and the value of the parameter N between young (unerupted) and mature (erupted) dentin minerals. It was ascertained that the occupancy of adsorption sites by Mg ions became greater with maturation of the dentin tissues. The overall results suggest that the Mg-mineral interaction in tooth and bone tissues may be a highly tissue-specific process, presumably reflecting differences in fluid composition (particularly Ca and Mg activities) responsible for biomineralization.  相似文献   
7.
We reported previously that Lixelle, which was used for beta-2 microglobulin (BMG) adsorption columns, could adsorb not only BMG but also inflammatory cytokines. We then were interested in the application of Lixelle to patients with systemic inflammatory response syndrome (SIRS) and tried to find out its ability to adsorb microorganism components in vitro using lipopolysaccharide (LPS) (E. coli: B8), endotoxin (ET) containing water, and peptidoglycan (PG: Micrococcus luteus). The initial concentrations of each solution were LPS (ET: 29,135 EU/L), contaminated water (ET: 3,523 EU/L), and PG (67.1 ng/ml) and 2.5 ml of each of the stock solutions and adjusted diluted solutions contained 0.5 ml of Lixelle beads. After shaking at 37 degrees C for 2 h, ET in the solutions was determined by the ET specific-limulus amebocyte lysate (ES-LAL) method and PG by the silkworm larbae plasma (SLP) method. The results revealed that even when ET concentrations in LPS and contaminated water were high, the samples containing Lixelle beads showed significant decreases. There was some adsorption of PG but no significant differences. Thus, Lixelle beads can adsorb not only BMG but also microorganism components such as ET and PG. These findings, together with the ability to adsorb inflammatory cytokines by Lixelle, show the possibility of application for the treatment of infectious SIRS.  相似文献   
8.
蒙脱石散对盐酸左氧氟沙星体外吸附的影响   总被引:7,自引:0,他引:7  
马洪峰  李庆 《中国药师》2004,7(7):538-539
目的: 探讨蒙脱石散对盐酸左氧氟沙星体外吸附的影响.方法: 采用不同剂量的盐酸左氧氟沙星分别与3 g蒙脱石散混合,加入0.1 mol·L-1盐酸溶液中,在(37±0.5)℃水浴中恒温2 h后过滤,用紫外分光光度法测定盐酸左氧氟沙星的含量变化.结果: 蒙脱石散对盐酸左氧氟沙星的吸附率为(98.37±0.03)%.结论: 蒙脱石散对盐酸左氧氟沙星有极强吸附,因此应避免两种药物同时服用.  相似文献   
9.
一次性输液连接管和输液针对硝酸甘油的吸附作用研究   总被引:2,自引:0,他引:2  
目的:研究微泵维持静脉注射时一次性输液连接管和输液针对硝酸甘油的吸附作用。方法:模拟临床微泵维持静脉注射,用高效液相色谱法、紫外分光光度法定量分析硝酸甘油在注射过程中的浓度变化。结果:一次性输液连接管和输液针对硝酸甘油具有显著的吸附作用,8h内平均吸附率为(73 .88±2. 05) %。结论:硝酸甘油经微泵维持静脉注射时,不宜使用对硝酸甘油具有吸附作用的一次性输液连接管和输液针  相似文献   
10.
肝苏缓释胶囊精制工艺中大孔吸附树脂型号的筛选   总被引:1,自引:1,他引:1  
目的筛选适合分离纯化赶黄草提取物的最佳大孔吸附树脂型号。方法以槲皮素吸附量、解吸率、吸附速率及解吸速率为指标,对D140、D141、D3520、AB-8、D101、DM-130、NKA-9、S-8等8种大孔吸附树脂的性能进行比较。结果8种大孔吸附树脂对槲皮素的静态吸附量顺序为:D140>D141>D3520>AB-8>D101>DM-130>NKA-9>S-8,解吸率顺序为:D140>D141>S-8>AB-8>NKA-9>D3520>DM-130>D101。其中D140、D141对槲皮素的吸附量分别为9.728、.76m.g-1,解吸率分别为88.5%、84.3%;吸附速率和解吸速率比较结果表明,D140型树脂在加入药液后约5h吸附达到平衡,在加入解吸剂后1.5h解吸完全,其吸附、解吸速率最快。结论在8种树脂中,D140的吸附与解吸效果最佳。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号