全文获取类型
收费全文 | 288篇 |
免费 | 27篇 |
专业分类
各国政治 | 1篇 |
工人农民 | 2篇 |
世界政治 | 2篇 |
外交国际关系 | 2篇 |
法律 | 268篇 |
中国政治 | 4篇 |
政治理论 | 1篇 |
综合类 | 35篇 |
出版年
2023年 | 6篇 |
2022年 | 7篇 |
2021年 | 10篇 |
2020年 | 9篇 |
2019年 | 9篇 |
2018年 | 7篇 |
2017年 | 8篇 |
2016年 | 13篇 |
2015年 | 16篇 |
2014年 | 18篇 |
2013年 | 24篇 |
2012年 | 21篇 |
2011年 | 23篇 |
2010年 | 15篇 |
2009年 | 30篇 |
2008年 | 19篇 |
2007年 | 14篇 |
2006年 | 11篇 |
2005年 | 8篇 |
2004年 | 6篇 |
2003年 | 7篇 |
2002年 | 3篇 |
2001年 | 8篇 |
2000年 | 9篇 |
1998年 | 5篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1984年 | 1篇 |
排序方式: 共有315条查询结果,搜索用时 15 毫秒
221.
Ailiang Chen M.Sc. Guoqing Wang M.Sc. Qin Cao B.Sc. Yan Wang M.Sc. Zhaohui Zhang Ph.D. Yimin Sun M.Sc. Hui Wang M.Sc. Chaoyi Xu B.Sc. Qi Zhou B.Sc. Pei Han B.Sc. Miao Liu B.Sc. Yang Yang B.Sc. Wanli Xing Ph.D. Keith R. Mitchelson Ph.D. Jing Cheng Ph.D. 《Journal of forensic sciences》2009,54(4):953-960
Abstract: The abuse of antibiotic drugs during animal production remains a worldwide problem and the subsequent detection of the residues of various drugs present at low concentrations in complex biological matrices poses significant analytical challenges. The present study outlines a practical biochip assay system to identify antibiotic residues in different animal tissue extracts. The system uses a simple but efficient multiresidue sample extraction procedure to isolate the antibiotic residues which were then identified directly using high‐affinity monoclonal antibodies presented in a competitive immunoassay with conjugated antibiotic hapten‐chips. The hapten‐chip can analyze six samples each for eight antibiotics on a single chip within 3 h. The analytical results with both artificial positive standard samples and the incurred samples show that the antibody hapten‐chip system has a comparable accuracy and a similar sensitivity to a standard ultra performance liquid chromatography–mass spectrometry (MS)/MS assay. In conclusion, an effective analytical screening system based on antibody hapten‐chip was developed for detecting multiple antibiotic residues from multiple samples. 相似文献
222.
Timothy J. Verdon B.Sc. Robert J. Mitchell Ph.D. Roland A. H. van Oorschot Ph.D. 《Journal of forensic sciences》2014,59(4):1080-1089
Currently, there is a variety of swabs for collection of biological evidence from crime scenes, but their comparative efficiency is unknown. Here, we report the results of an investigation into the efficiency of different swab types to collect blood, saliva and touch DNA from a range of substrates. The efficiency of extracting blood and saliva from each swab type was also tested. Some swabs were significantly more effective than others for sampling biological materials from different substrates. Swabs with the highest sampling efficiency, however, often did not have the highest extraction efficiency. Observations were recorded regarding practicality of each swab in a variety of situations. Our study demonstrates that selection of sampling device impacts greatly upon successful collection and extraction of DNA. We present guidelines to assist in evaluation of swab choice. 相似文献
223.
224.
Kopka J Leder M Jaureguiberry SM Brem G Boselli GO 《Journal of forensic sciences》2011,56(5):1235-1240
Abstract: Obtaining complete short tandem repeat (STR) profiles from fingerprints containing minimal amounts of DNA, using standard extraction techniques, can be difficult. The aim of this study was to evaluate a new kit, Fingerprint DNA Finder (FDF Kit), recently launched for the extraction of DNA and STR profiling from fingerprints placed on a special device known as Self‐Adhesive Security Seal Sticker® and other latent fingerprints on forensic evidentiary material like metallic guns. The DNA extraction system is based on a reversal of the silica principle, and all the potential inhibiting substances are retained on the surface of a special adsorbent, while nucleic acids are not bound and remain in solution dramatically improving DNA recovery. DNA yield was quite variable among the samples tested, rendering in most of the cases (>90%) complete STR profiles, free of PCR inhibitors, and devoid of artifacts. Even samples with DNA amount below 100 pg could be successfully analyzed. 相似文献
225.
226.
目的建立血样中4种常见巴比妥类药物的固相萃取方法。方法采用Oasis MAX固相萃取柱对样品进行预处理,以2%氨水淋洗2,%甲酸-甲醇洗脱,GC/NPD定量检验,GC/MS定性检验。结果血样中4种常见巴比妥类药物平均萃取回收率达80%以上,以信噪比10/1计,最小定量限为1~2μg/mL,以信噪比3/1计,检出限为0.5~1μg/mL,在1~50μg/mL范围内,线性相关系数均在0.99以上。结论本文固相萃取方法检出限低,回收率高,选择性强,可应用于血样中4种常见巴比妥类药物的检测。 相似文献
227.
目的通过对DNA碱性裂解提取法进行优化和改进,建立一种操作更简便、检验快速、结果更可靠的生物检材DNA提取方法。方法以抗凝血作为检验样本,通过改变提取试剂的浓度、pH值、保存时间及孵化样本的温度、时间等条件,观测对检验结果峰值的影响,以确定提取试剂最佳条件,DNA提取物最佳保存条件。通过用改良后的碱性裂解法及Chelex100法同时提取不同量的抗凝血样本、各类法医生物检材,用不同厂家的DNA试剂盒扩增,对碱性裂解法的灵敏度、适应性和适用性进行评估。结果改良后的碱性裂解法只需将生物检材用NaOH(0.25mol/L)99℃孵化8min,振荡后加入TrisHCl(0.05mol/L,pH=6.5)中和液,离心后直接扩增检测。DNA提取物于-20℃冰箱可长期保存。对于毛发及精斑类检材优于Chelex100法。DNA提取物适用于现有各种DNA试剂盒扩增检测,其灵敏度与Chelex100法相似。结论改良后的碱性裂解法,操作简便、检验快速、结果可靠,可适合于法庭科学的检案与建库。 相似文献
228.
Laza D Nys B Kinder JD Kirsch-De Mesmaeker A Moucheron C 《Journal of forensic sciences》2007,52(4):842-850
In traditional scanning electron microscopy/energy dispersive X-ray analysis of gunshot residue (GSR), one has to cope more and more frequently with limitations of this technique due to the use of lead-free ammunition or ammunition lacking heavy metals. New methods for the analysis of the organic components of common propellant powder stabilizers were developed based on liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). A multiple reactions monitoring scanning method was created for the screening of akardite II, ethylcentralite, diphenylamine, methylcentralite, N-nitrosodiphenylamine, 2-nitrodiphenylamine, and 4-nitrodiphenylamine, present in standards mixtures. Five out of seven of these target compounds can be selectively identified and distinguished from the two others with a high accuracy. Samples from the hands of a shooter were collected by swabbing and underwent solid phase extraction prior to analysis. Detection limits ranging from 5 to 115 mug injected were achieved. Results from several firing trials show that the LC-MS/MS method is suitable for the detection of stabilizers in samples collected following the firing of 9 mm Para ammunitions. 相似文献
229.
Norris JV Manning K Linke SJ Ferrance JP Landers JP 《Journal of forensic sciences》2007,52(4):800-805
This report focuses on the development of a method for chemically induced enhancement of cell elution and recovery from cotton swabs. The method exploits the exclusive use of detergents for intact cell removal, and can be utilized in conjunction with, or to circumvent, conventional differential extraction (DE). Samples treated with Sarkosyl (54.4 +/- 1.8%) and sodium dodecyl sulfate (SDS) (78.5 +/- 0.7%) yielded higher sperm cell recoveries than a conventional DE buffer (39.4 +/- 2.1%). The results indicated that the choice of detergent affected sperm cell yield, with anionic detergents having the greatest effect. Storage time of samples affected the concentration of detergent required for optimal sperm cell recovery, longer times requiring increased detergent concentrations. In addition, the extent of sperm cell lysis by proteinase K digestion was evaluated. The results indicate that the exclusive use of SDS enhances the release of sperm and epithelial cells from a cotton swab as compared with DE buffer, providing for a more effective DNA analysis. 相似文献
230.
A rapid and simple gas chromatography-mass spectrometry (GC-MS) method was developed and validated for the simultaneous detection and quantification of five psychotropic phenylalkylamines (amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, and norketamine) in toenails. After external decontamination, nail clippings were mechanically pulverized with a bead mill and then incubated in methanol under ultrasonication at 50°C for 1 h. The resulting solutions were evaporated to dryness, derivatized, and analyzed by GC-MS. The intra- and inter-day precisions were within 10.7% and 13.9%, respectively. The intra- and inter-day accuracies were -4.2% to 5.0% and -2.4% to 8.4%, respectively. Limits of detection and quantification for each analyte were lower than 0.024 and 0.08 ng/mg, respectively. The recoveries were in the range of 80.6-87.5%. The results indicated that the proposed method is a simple, rapid, accurate, and precise for quantification of five phenylalkylamines in nails. The method was successfully applied to the simultaneous detection and quantification of phenylalkylamines in nail samples of possible drug abusers. 相似文献