全文获取类型
收费全文 | 1178篇 |
免费 | 52篇 |
国内免费 | 62篇 |
专业分类
化学 | 358篇 |
力学 | 4篇 |
综合类 | 16篇 |
数学 | 24篇 |
物理学 | 99篇 |
综合类 | 791篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 27篇 |
2021年 | 29篇 |
2020年 | 24篇 |
2019年 | 29篇 |
2018年 | 20篇 |
2017年 | 29篇 |
2016年 | 40篇 |
2015年 | 29篇 |
2014年 | 48篇 |
2013年 | 36篇 |
2012年 | 85篇 |
2011年 | 52篇 |
2010年 | 58篇 |
2009年 | 58篇 |
2008年 | 60篇 |
2007年 | 85篇 |
2006年 | 72篇 |
2005年 | 65篇 |
2004年 | 52篇 |
2003年 | 56篇 |
2002年 | 63篇 |
2001年 | 39篇 |
2000年 | 38篇 |
1999年 | 24篇 |
1998年 | 30篇 |
1997年 | 32篇 |
1996年 | 19篇 |
1995年 | 11篇 |
1994年 | 12篇 |
1993年 | 10篇 |
1992年 | 11篇 |
1991年 | 6篇 |
1990年 | 10篇 |
1989年 | 9篇 |
1988年 | 5篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1982年 | 3篇 |
1978年 | 1篇 |
排序方式: 共有1292条查询结果,搜索用时 15 毫秒
31.
介绍了非接触式IC卡和读卡器的功能组成,讨论了非接触式IC卡在门禁系统中的应用,给出了相关硬件、软件的设计思路。 相似文献
32.
基于Rijndael算法的IC卡医保系统设计 总被引:1,自引:0,他引:1
介绍了Rijndael算法的设计原理、实现方法、目前存在的攻击方法,以及Rijndael算法在医保系统中的具体实现,分析了指纹IC卡的特点,提出了基于Rijndael算法的IC卡医保系统的设计原则和安全措施,还讨论了指纹识别技术在IC卡医保系统中的应用。 相似文献
33.
根据目前国内公交收费的发展趋势,设计出用于对客流等数据采集的IC卡自动收费系统,并提出利用它来进行客流等数据采集、处理的新方案.与人工调查相比,它的投入小得多,并且可以提供大量详细、准确的动态数据,对城市公交以及公交的智能化调度、线路的开辟、优化、站点的设置等都具有极其重要的意义. 相似文献
34.
Zymogen granule (ZG) constituents play important roles in pancreatic injury and disease. In previous studies, proteomic analyses with rat zymogen granules were separated by two‐dimensional gel electrophoresis or one‐dimensional SDS–PAGE, followed by in‐gel tryptic digestion. In order to overcome the disadvantage of in‐gel digestion and to carry out further in‐depth proteomic analysis of the zymogen granules, in this study, by combining a filter‐aided sample preparation method and fully automated 2D‐LC‐MS/MS technique, 800 ZG proteins were identified with at least two unique peptides for each protein, 75% of which have not been previously reported. The identified proteins revealed broad diversity in protein identity and function. This is the largest dataset of ZG proteome, and also the first dataset of the mouse ZG proteome, which may help elucidate on the molecular architecture of ZGs and their functions. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
35.
Copper(II) complexes of the type [Cu(SPF)(Ln)Cl] (where SPF is sparfloxacin and Ln = substituted terpyridines) were synthesized and found to have a distorted octahedral geometry. Superoxide dismutase‐like activity of the complexes was measured using a nitroblue tetrazolium/reduced nicotinamide adenine dinucleotide/phenazine methosulfate system and expressed in terms of the concentration of complex which terminates the formation of formazan by 50% (IC50 value), which was found to range from 0.572 to 1.522 µm . Interactions of the complexes with herring sperm DNA were studied by absorption titration, viscosity measurement and gel electrophoresis under physiological conditions. The antimicrobial efficiency of the complexes was tested against five different microorganisms and showed good biological activity. All the complexes showed good cytotoxic activity, with LC50 values ranging from 4.01 to 9.64 µg ml?1. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
36.
Ashok Zakkula Sreekanth Dittakavi Malika Muskan Maniyar Naveem Syed Suresh P. Sulochana Mohd Zainuddin Ramesh Mullangi 《Biomedical chromatography : BMC》2019,33(11)
Isocitrate dehydrogenase (IDH) inhibitors comprise a novel class of anticancer drugs, which are approved to treat acute myeloid leukemia patients having mutations on IDH1/2. We report the development and validation of a high‐performance liquid chromatography (HPLC) method for the simultaneous quantitation of IDH inhibitors, namely enasidenib (EDB), ivosidenib (IDB) and vorasidenib (VDB), in mouse plasma as per the US Food and Drug Administration regulatory guidelines. The method involves extraction of EDB, IDB and VDB along with internal standard (IS; phenacetin) from mouse plasma (100 μl) using a simple protein precipitation process. The chromatographic analysis was performed on an HPLC system using a gradient mobile phase (comprising 10 mm ammonium acetate and acetonitrile in a flow‐gradient) and an X‐Terra Phenyl column. The UV detection wave length was set at λmax 265 nm. EDB, IDB, VDB and the IS eluted at 7.36, 8.60, 9.50 and 5.12 min, respectively, with a total run time of 10 min. The calibration curve was linear over a concentration range of 0.20–12.5 μg/ml for EDB and 0.50–12.5 μg/ml for IDB and VDB (r2 = ≥0.998 for all of the analytes). Validation results met the acceptance criteria. The validated HPLC method was successfully applied to a pharmacokinetic study in mice. 相似文献
37.
Jessica Silva Joo Basso Joo Sousa Ana Fortuna Carla Vitorino 《Biomedical chromatography : BMC》2019,33(10)
There is increasing interest in atorvastatin and curcumin owing to their potential anticancer activity. A new, accurate and sensitive HPLC method was developed, for the first time, to simultaneously quantify atorvastatin and curcumin in mouse plasma and brain, liver, lung and spleen tissues following protein precipitation sample preparation. The chromatographic separation was achieved in 13 min on a C18 column, at 35°C, using a mobile phase composed of acetonitrile–methanol–2% (v/v) acetic acid (37.5:2.5:60, v/v/v) at a flow rate of 1.0 mL/min. The detection of analytes and internal standard was carried out at 247, 425 and 250 nm, respectively. According to international guidelines, the method was shown to be selective, with lower limits of quantification ranging from 10 to 500 ng/mL for curcumin, and from 100 to 600 ng/mL for atorvastatin, linear over a wide concentration range (r2 ≥ 0.9971) and with acceptable accuracy (bias ± 12.29%) and precision (coefficient of variation ≤13.15%). The analytes were reproducibly recovered at a percentage >81.10% and demonstrated to be stable under various experimental conditions in all biological matrices. This method can be easily applied to in vivo biodistribution studies related to the intranasal administration of atorvastatin and curcumin, separately or simultaneously. 相似文献
38.
Pharmacokinetics and metabolism study of veratramine in mice after oral administration using LC‐MS/MS
下载免费PDF全文
![点击此处可从《Biomedical chromatography : BMC》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Yue Cong Jun‐Li Zhang Sha‐Sha Li Shan Shen Jiang‐Ying Wang Zongwei Cai 《Biomedical chromatography : BMC》2016,30(9):1515-1522
A simple and sensitive high‐performance liquid chromatography coupled with hybrid triple quadrupole–linear ion trap mass spectrometry (Q‐trap‐MS) method was developed and validated for the determination of veratramine, the major bioactive and neurotoxic component in Veratrum nigrum L. Veratramine and the internal standard (IS) were separated with a Waters Symmetry C18 column and eluted with a gradient mobile phase system containing acetonitrile and 0.1% aqueous formic acid. The analysis was performed by using positive electrospray ionization mode with multiple reaction monitoring (MRM). Transition ions of m/z 410.2 → 295.2 for veratramine and m/z 426.1 → 113.8 for the IS were monitored. The method was validated with a good linearity in the range of 1–1000 ng/mL and lower limit of quantification of 1 ng/mL. The precision (CV) of intra‐ and inter‐day ranged from 3.92 to 7.29%, while the accuracy (bias) intra‐ and inter‐day were between ?4.78 and 1.65%. The recovery, stability and matrix effect were within the acceptable ranges. Five metabolites of veratramine, including four hydroxylated and one sulfated metabolites, were tentatively identified using predictive MRM–information dependent acquisition–enhanced product ion mode (predictive MRM‐IDA‐EPI). The developed method was successfully applied to the pharmacokinetic and metabolic study of veratramine in mice after oral administration of veratramine. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
39.
Harsha K. Tripathy S. V. Nair Manju Rama Murthy Bestha Vinay Kiran Sreekanth Dittakavi Ramesh Mullangi 《Biomedical chromatography : BMC》2022,36(8):e5387
In this study, we report the development and validation of an LC–tandem mass spectrometry method for the simultaneous quantitation of bendamustine and copanlisib in mouse plasma as per the US FDA regulatory guidelines. The sample processing involves extraction of bendamustine and copanlisib along with internal standard (IS; warfarin) from 50 μL mouse plasma using a liquid–liquid extraction method. The chromatographic separation of bendamustine, copanlisib and the IS was achieved on an Atlantis dC18 column using an isocratic mobile phase (5 mM ammonium acetate:methanol, 20:80 v/v). Bendamustine, copanlisib and the IS eluted at 0.88, 1.39 and 0.74 min, respectively, with a total run time of 2.5 min. The calibration curve ranged from 3.99–2996 and 4.33–3248 ng/mL for bendamustine and copanlisib, respectively. Inter- and intra-day precision and accuracy, stability in processed samples and upon storage, dilution integrity and incurred sample reanalysis were investigated for both the analytes. The intra- and inter-day precisions were in the ranges of 2.01%–5.05% and 2.74%–6.13% and 1.98%–7.64 and 8.62%–9.04% for bendamustine and copanlisib, respectively. Stability studies showed that both analytes were stable on bench top for 6 h, in auto-sampler for 24 and at −80°C for 30 days. The validated method was successfully applied to a pharmacokinetic study in mice. 相似文献
40.
A simple, sensitive and rapid assay method has been developed and validated as per regulatory guidelines for the estimation of enasidenib on mouse dried blood spots (DBS) using liquid chromatography coupled to tandem mass spectrometry with electrospray ionization in the positive‐ion mode. The method employs liquid extraction of enasidenib from DBS disks of mouse whole blood followed by chromatographic separation using 0.2% formic acid–acetonitrile (25:75, v/v) at a flow rate of 1.0 mL/min on an Atlantis dC18 column with a total run time of 2.0 min. The MS/MS ion transitions monitored were m/z 474.0 → 267.1 for enasidenib and m/z 309.2 → 251.3 for the internal standard (warfarin). The assay was linear in the range of 1.01 – 3044 ng/mL. The within‐run and between‐run precisions were in the range of 3.18 – 9.06 and 4.66 – 8.69%, respectively. Stability studies showed that enasidenib was stable on DBS cards for 1 month. This novel method has been applied to analyze the DBS samples of enasidenib obtained from a pharmacokinetic study in mice. 相似文献