全文获取类型
收费全文 | 468篇 |
免费 | 43篇 |
国内免费 | 37篇 |
专业分类
基础医学 | 3篇 |
临床医学 | 7篇 |
内科学 | 3篇 |
神经病学 | 1篇 |
特种医学 | 10篇 |
外科学 | 6篇 |
综合类 | 64篇 |
预防医学 | 34篇 |
药学 | 341篇 |
中国医学 | 79篇 |
出版年
2023年 | 6篇 |
2022年 | 7篇 |
2021年 | 9篇 |
2020年 | 14篇 |
2019年 | 8篇 |
2018年 | 14篇 |
2017年 | 10篇 |
2016年 | 15篇 |
2015年 | 33篇 |
2014年 | 27篇 |
2013年 | 20篇 |
2012年 | 59篇 |
2011年 | 52篇 |
2010年 | 40篇 |
2009年 | 24篇 |
2008年 | 20篇 |
2007年 | 22篇 |
2006年 | 17篇 |
2005年 | 12篇 |
2004年 | 14篇 |
2003年 | 12篇 |
2002年 | 10篇 |
2001年 | 12篇 |
2000年 | 10篇 |
1999年 | 12篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 5篇 |
1995年 | 5篇 |
1994年 | 7篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 5篇 |
1990年 | 9篇 |
1989年 | 5篇 |
1988年 | 5篇 |
1987年 | 1篇 |
1985年 | 2篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1980年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有548条查询结果,搜索用时 31 毫秒
1.
Novel techniques have recently emerged to separate chiral drug compounds into pure enantiomers. The mechanism, experimental difficulties, and applicability of these methods can vary greatly, and the choices involved are not straightforward. The most significant new advances in the field of chiral separations have come from work done with liquid chromatographic systems and chiral stationary-phase columns. This review describes several commonly used approaches to chiral separation, diastereomeric derivatization, chiral mobile-phase additives, and three major types of chiral stationary phases. Although no single method can be judged superior for every drug application, it appears that chiral stationary phases have received the most attention recently and they are emphasized here. 相似文献
2.
硫酸小诺霉素注射液的紫外分光光度测定 总被引:2,自引:0,他引:2
采用紫外分光光度法测定硫酸小诺霉素注射液的含量,以邻苯二醛为衍生化试剂,测定波长333nm。在2 ̄20u/ml范围内呈线性关系,r=0.9999。平均回收率为100.0%,RSD为0.82%。本法简便、快速,结果准确。 相似文献
3.
建立了水产品中多组分生物胺的反相高效液相色谱-柱后衍生-荧光检测方法。采用荧光试剂邻苯二甲醛(OPA)为柱后衍生化试剂,在Capcell Pak MG-C18色谱柱上,通过梯度洗脱使酪胺、腐胺、尸胺、组胺、胍丁胺、精胺和亚精胺等7种生物胺得到良好分离,在给定的浓度范围内,各组分生物胺呈现良好线性相关(R^2〉0.999)。在水产品中添加生物胺混合标准溶液,平均回收率为88.3%~110.1%,相对标准偏差RSD小于10%。结合水产品的感官鉴定、pH值和TVBN值测定等方法检测水产食品的新鲜程度,分析了鱿鱼在不同保藏温度、保藏时间下的生物胺种类及含量的变化。其中胍丁胺和尸胺在鱿鱼的保藏过程中发生最显著变化,可以作为其质量变化的参考指标。 相似文献
4.
Sternson LA Stobaugh JF Reid TJ de Montigny P 《Journal of pharmaceutical and biomedical analysis》1988,6(6-8):657-668
The bioanalysis of drugs used in the management of cancer is often complicated by the lack of selectivity and sensitivity. Chemical derivatization of these drugs prior to their chromatographic analysis represents a viable strategy to improve chromatographic resolution and to enhance detectability. This review provides examples of how this approach can meet these objectives. Derivatization of racemic cyclophosphamide with a chiral acylating agent, following hydroxyalkylation to introduce a reactive centre into the molecule, provides the basis for its stereospecific analysis. The analysis of dianhydrogalactitol is described, in which diethyldithiocarbamate is used as a nucleophilic derivatizing agent that improves chromatographic behaviour and analytical sensitivity. The final example that is described is the design and preparation of improved fluorogenic reagents (o-phthalaldehyde analogues) for the derivatization of peptides and application of these reagents to the trace analysis of leu-enkephalin in plasma. 相似文献
5.
Pivnichny JV 《Journal of pharmaceutical and biomedical analysis》1984,2(3-4):491-500
The two isomeric components of glycerol formal, 1,3-dioxan-5-ol and 1,3-dioxolane-4-methanol, are marginally separated (Rs = 1.0) by polar-bonded-phase high-performance liquid chromatography (HPLC) on a cyanopropyl column with acetone—hexane as the eluent. Esterification of these components with 3,5-dinitrobenzoyl chloride produces derivatives which are, however, completely resolved (Rs > 2) by normal-phase HPLC on silica; derivatization has the added advantage of introducing an ultraviolet-absorbing chromophore into each component. Preparative scale chromatography is used to isolate each of the derivatives, which are characterized by their UV, NMR and mass spectral properties. These esters are used as reference standards for an analytical method based on derivatization and normal-phase chromatography. In this way a sample of glycerol formal is calibrated for use as a standard in the direct determination of the two components by polar-bonded-phase HPLC. 相似文献
6.
Several approaches to the separation of four stereoisomers, 1–4, of a novel, topically active, carbonic anhydrase inhibitor, 1, with two chiral centers in the molecule and four isomers, 5–8, of its chiral metabolite, 5, were evaluated. These methods include nonchiral derivatization followed by separation on chiral stationary phases (CSPs) and chiral derivatization and separation on nonchiral columns and on CSPs. Baseline separation of stereoisomers 1–4 was achieved in less than 15 min after chiral derivatization with (S)-(+)-l-(l-naphthyl)ethyl isocyanate (NEIC) and chiral chromatography on a (R)-N-(3,5-dinitrobenzoyl)phenyl glycine (DNBPG) column under normal phase (NP) conditions. Similarly, isomers 5-8 were baseline separated in less than 20 min after derivatization with NEIC and chromatography on nonchiral (nitrophenyl) and chiral [(S)-(3,5-dinitrobenzoyl)leucine; DNBL] columns in series under the same NP chromatographic conditions. Only partial separation of the diastereomeric derivatives was observed on a variety of nonchiral columns. In addition, all other direct and indirect chiral separation approaches gave only partial separation of at least two stereoisomers within the group of 1–4 or 5–8. The details of chiral separations using various methods and separation () and capacity factors (k) of the derivatized isomers 1–8 on a series of chiral and nonchiral columns are presented. Using these methods, the absolute configuration of the human metabolite of 1 was established as S
1
S
2 (5), and the heat (HD) and light (LD) degradation products of 1 as R
1
S
2 (3) and S1
S
2 (5), respectively. 相似文献
7.
Optimum conditions of chiral derivatization reaction of beta-blockers acebutolol, arotinolol, beta-xolol, bisoprolol, celiprolol, metoprolol and pindolol) with (-)-menthyl chloroformate were investigated for the resolution by HPLC. With more than 30 times molar excess of (-)-menthyl chloroformate chiral derivatization reactions were completed within one hour at room temperature except arotinolol and celiprolol. Diastereomeric derivatives of beta-blockers were well resolved on the ODS column using acetonitrile-methanol-water as a mobile phase. 相似文献
8.
目的 根据具有趋骨性的化合物的共同特征,设计并合成苯并吡喃-4-酮类化合物,检测它们的趋骨性。方法 以苯并吡喃-4-酮为核心,设计并合成了6个在其3位、5位、6位有酚羟基、甲氧基、羧基、酯基、甲氧羰甲氧基等基团的衍生物,用羟基磷灰石吸附实验检测其趋骨性。结果 所有合成的目标化合物的结构均经过IR,^1H—NMR和MS确认。结论 部分设计的苯并吡喃-4-酮衍生物具有比四环紊更好的趋骨性。 相似文献
9.
柱前衍生高效液相色谱法测定人血浆中尿囊素浓度 总被引:2,自引:0,他引:2
目的:建立血浆中尿囊素的浓度测定方法.方法:采用柱前衍生反相高效液相色谱法,尿囊素与2,4-二硝基苯肼(DNPH)反应生成2,4-二硝基苯腙,色谱柱为PhenomeneJx,D Luna C18色谱柱(150mm×4.6mm,5μm),柱温为室温.流动相A为0.2%冰醋酸(用三乙胺调pH至5.0),流动相B为乙腈.梯度洗脱程序:A与B的体积比变化为0~3min 85∶15~65∶35(曲线系数为7),3~5min 65∶35~15∶85 (曲线系数为7),5~9min 15∶85~15∶85 (曲线系数为6),9~10min 15∶85~85∶15(曲线系数为6),10~15min 85∶15(曲线系数为6).PAD检测波长:340nm,流速1.0mL·min-1.内标为加替沙星.结果:在此色谱条件下,尿囊素衍生物与血浆中其他成分的分离完全,线性检测范围为2.5~40mg·L-1,最低检测浓度为2.5mg·L-1,相对回收率在99.35%~103.14%之间,日内及日间精密度RSD小于2.1%.结论:柱前衍生反相高效液相色谱法稳定、灵敏、可靠,可用于人体血浆中尿囊素浓度的测定. 相似文献
10.
柱前衍生化HPLC法测定百多宁注射液中的脂肪酸含量 总被引:4,自引:0,他引:4
目的建立以HPLC法测定百多宁注射液中脂肪酸含量的方法。方法采用无水硫酸钠破乳方法分离百多宁注射液中的油相。以 2 ,4′ 二溴苯乙酮为衍生化试剂 ,18-冠 - 6醚为相转移催化剂 ,采用C8反相柱 ,以乙腈 -水 (V∶V =75∶2 5 )为流动相等度洗脱 ,正十七烷酸为内标 ,一次基线分离 4种脂肪酸。结果亚油酸在 4 6~ 30 7ng内、软脂酸在 2 7 2~ 181 0ng内、油酸在 14 4~96 0ng 内、硬脂酸在 9 7~ 6 5 1ng内质量与相对峰面积线性关系良好 ,相关系数分别为 0 9997、0 9999、0 9995、0 9996。平均回收率分别为 98 2 %、97 5 %、99 8%、10 2 3% ,RSD分别为2 6 %、3 0 %、1 2 %、2 4 %。结论方法重现性好、定量准确 ,可作为百多宁注射液中脂肪酸测定的定量方法 相似文献