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981.
Janine Schulte MSc Nicole Rittiner MSc Ilona Seiberle MSc Sarah Kron Iris Schulz PhD 《Journal of forensic sciences》2023,68(4):1133-1147
Touch DNA has become increasingly important evidence in todays' forensic casework. However, due to its invisible nature and typically minute amounts of DNA, the collection of biological material from touched objects remains a particular challenge that underscores the importance of the best collection methods for maximum recovery efficiency. So far, swabs moistened with water are often utilized in forensic crime scene investigations for touch DNA sampling, even though an aqueous solution provokes osmosis, endangering the cell's integrity. The aim of the research presented here was to systematically determine whether DNA recovery from touched glass items can be significantly increased by varying swabbing solutions and volumes compared with water-moistened swabs and dry swabbing. A second objective was to investigate the possible effects of storage of swab solutions prior to genetic analysis on DNA yield and profile quality when stored for 3 and 12 months, as is often the case with crime scene samples. Overall, the results indicate that adapting volumes of the sampling solutions had no significant effect on DNA yield, while the detergent-based solutions performed better than water and dry removal, with the SDS reagent yielding statistically significant results. Further, stored samples showed an increase in degradation indices for all solutions tested, but no deterioration in DNA content and profile quality, allowing for unrestricted processing of touch DNA samples stored for at least 12 months. One further finding was a strong intraindividual change in DNA amounts observed over the 23 deposition days which may be related to the donor's menstrual cycle. 相似文献
982.
Natalia Czado MS Bobby LaRue PhD Amanda Wheeler MS Rachel Houston PhD Amy Holmes PhD Kelly Grisedale PhD Sheree Hughes PhD 《Journal of forensic sciences》2023,68(2):596-607
Formalin-fixed tissues provide the medical and forensic communities with alternative and often last resort sources of DNA for identification or diagnostic purposes. The DNA in these samples can be highly degraded and chemically damaged, making downstream genotyping using short tandem repeats (STRs) challenging. Therefore, the use of alternative genetic markers, methods that pre-amplify the low amount of good quality DNA present, or methods that repair the damaged DNA template may provide more probative genetic information. This study investigated whether whole genome amplification (WGA) and DNA repair could improve STR typing of formaldehyde-damaged (FD) tissues from embalmed cadavers. Additionally, comparative genotyping success using bi-allelic markers, including INDELs and SNPs, was explored. Calculated random match probabilities (RMPs) using traditional STRs, INDEL markers, and two next generation sequencing (NGS) panels were compared across all samples. Overall, results showed that neither WGA nor DNA repair substantially improved STR success rates from formalin-fixed tissue samples. However, when DNA from FD samples was genotyped using INDEL and SNP-based panels, the RMP of each sample was markedly lower than the RMPs calculated from partial STR profiles. Therefore, the results of this study suggest that rather than attempting to improve the quantity and quality of severely damaged and degraded DNA prior to STR typing, a more productive approach may be to target smaller amplicons to provide more discriminatory DNA identifications. Furthermore, an NGS panel with less loci may yield better results when examining FD samples, due to more optimized chemistries that result in greater allelic balance and amplicon coverage. 相似文献
983.
《Science & justice》2023,63(5):624-634
According to criminal botany, the offender unknowingly carries plant samples from the crime scene. Therefore, studying the genetic data of plants native to the crime scene can solve many ambiguities in the criminal files. In this regard, the aim of this study was to investigate the genome of 5 endemic plants in some areas of Iran with high crime rate. Quercus brantii, Curpressus arizonica, Crataegus pentagyna, Ziziphus Spina-chtista, and Buxus hyrcana were assessed using 1 genetic fragment on plastid regions (trnH-psbA) as well as 1 gene on nuclear chromosome called ITS. The alignment of DNA sequences of trnH-psbA and ITS genes was done using BioEdit, Clustal X, and Muscle v4.0 software programs. The phylogenetic analysis was performed on aligned data using Maximum Parsimony (MP) and the Bayesian methods. The Splits Tree v.4.14.4 software program was used for phylogenetic network analysis. Finally, the data combinability test was conducted using the Incongruence Length Difference (ILD) test by PAUP* software program. All data from nrDNA ITS and trnH-psbA sequences were consistent with Information Compatibility Test (ICT) results. Moreover, the nrDNA ITS indicated more resolved relationship than trnH-psbA. The results from MP and Bayesian analyses did not differ significantly between singular and combined forms, except for a slight variance in confidence interval of branches. As the phylogenetic trees provide more thorough and deeper conception of species relations, it is hoped that they would be useful to illuminate some forensic gaps in regions with high crime rates enriched by these plants, not only in Iran, but also in all areas over the world with this vegetation. 相似文献
984.
为了研究湖南省华支睾吸虫分离株线粒体细胞色素c氧化酶第Ⅰ亚基(cox1)基因部分序列(pcox1)和烟酰胺腺嘌呤二核苷酸脱氢酶亚单位Ⅰ基因(nad1)部分序列(pnad1)的遗传变异情况,并用pcox1和pnad1序列构建华支睾吸虫与其他吸虫的种群遗传进化树。应用聚合酶链反应扩增华支睾吸虫虫株的pcox1和pnad1,应用ClustalX 1.81程序对序列进行比对,然后用Phylip3.67程序中的MP法和MEGA4.0程序NJ法绘制种系发育树,并用Puzzle5.2程序构建最大似然树。结果显示,所获得的pcox1和pnad1序列长度分别为1 100bp和790bp,种系发育进化表分析表明,25个华支睾吸虫分离株位于同一分枝。证实华支睾吸虫pcox1和pnad1序列种内相对保守,种间差异较大,故可作为种间遗传变异研究的标记,从而为华支睾吸虫的分类鉴定以及进一步的分子流行病学调查和群体遗传研究奠定基础。 相似文献
985.
Chin-Yuan Tzen Tsu-Yen Wu Hsin-Fu Liu 《Forensic Science International Supplement Series》2001,120(3):291
Analysis of the polymorphic sequences in mitochondrial DNA (mtDNA) has been widely applied to forensic tests and anthropology studies. However, these polymorphic data in human have thus far been derived from the displacement-loop and intergenic regions only. Here, we report the identification of clustered polymorphic sites in the mitochondria coding region encompassing position 8389–8865. The DNA sequences of 119 unrelated Chinese were determined by PCR amplification and direct sequencing. The results showed that heteroplasmy was found in five individuals, 39 sites were noted in this 477 bp region, and 41 haplotypes were identified. The probability of identity and allelic diversity were estimated as 0.1265 and 0.8809, respectively. The results suggest that sequence polymorphism from position 8389–8865 in human mtDNA can be used as a marker for identity investigation. 相似文献
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990.
大鼠脑细胞DNA含量与死亡时间关系的图像分析 总被引:47,自引:18,他引:29
运用计算机图像分析技术 ,对大鼠死后脑细胞DNA的变化进行观测 ,以寻找一种客观、量化的推断早期死亡时间的标准。实验选择 1 5只大鼠。处死后 ,在 2 4h内每隔 1h分别取脑细胞进行细胞学涂片、福尔马林液固定、Feulgen染色、自动图象分析仪测量、统计学处理。结果显示 :大鼠的早期死亡时间与其脑细胞DNA降解速率呈线性关系 ,其中积分光密度 (IOD)、平均灰度 (AG)、异形指数 (ID)提示本法有可能作为精确推断死亡时间 (PMI)的辅助手段。 相似文献