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Analogs and derivatives of traditional illicit drugs are ever increasing in variety and creativity. Staying abreast of the new developments is a constant challenge for every forensic laboratory. Recently, a seizure from Australian Customs Service presented our laboratory with the designer cathinone 3,4-dimethylmethcathinone (3,4-DMMC). Gas chromatography/mass spectrometry (GC/MS), liquid chromatography/mass spectrometry (LC/MS), nuclear magnetic resonance (NMR) spectroscopy, infrared (IR) spectroscopy, and ultraviolet (UV) spectrophotometry were employed to analyze the spectroscopic characteristics of this cathinone. As an analog, 3,4-DMMC exhibits similar if not identical IR and UV profiles to mephedrone (4-MMC) and methcathinone; however, the retention time from GC is unique as expected, and the electron impact fragmentation pattern is consistent with the fragmentation pattern of other cathinones. The chemical shifts of the carbons and hydrogens were assigned by both one- and two-dimensional NMR techniques, while the molecular weight was confirmed by LC/MS. 相似文献
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Jennifer R. Verkouteren M.S. Jessica L. Coleman M.S. Inho Cho B.S. 《Journal of forensic sciences》2010,55(2):334-340
Abstract: A method is described to perform automated mapping of hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine (RDX) particles in C‐4 fingerprints. The method employs polarized light microscopy and image analysis to map the entire fingerprint and the distribution of RDX particles. This method can be used to evaluate a large number of fingerprints to aid in the development of threat libraries that can be used to determine performance requirements of explosive trace detectors. A series of 50 C‐4 fingerprints were characterized, and results show that the number of particles varies significantly from print to print, and within a print. The particle size distributions can be used to estimate the mass of RDX in the fingerprint. These estimates were found to be within ±26% relative of the results obtained from dissolution gas chromatography/μ‐electron capture detection for four of six prints, which is quite encouraging for a particle counting approach. By evaluating the average mass and frequency of particles with respect to size for this series of fingerprints, we conclude that particles 10–20 μm in diameter could be targeted to improve detection of traces of C‐4 explosives. 相似文献
115.
Sabrina B. Sholts M.A. Sebastian K.T.S. Wärmländer Ph.D. Louise M. Flores B.A. Kevin W.P. Miller Ph.D. Phillip L. Walker Ph.D. 《Journal of forensic sciences》2010,55(4):871-876
Abstract: Three‐dimensional (3D) laser scanner models of human crania can be used for forensic facial reconstruction, and for obtaining craniometric data useful for estimating age, sex, and population affinity of unidentified human remains. However, the use of computer‐generated measurements in a casework setting requires the measurement precision to be known. Here, we assess the repeatability and precision of cranial volume and surface area measurements using 3D laser scanner models created by different operators using different protocols for collecting and processing data. We report intraobserver measurement errors of 0.2% and interobserver errors of 2% of the total area and volume values, suggesting that observer‐related errors do not pose major obstacles for sharing, combining, or comparing such measurements. Nevertheless, as no standardized procedure exists for area or volume measurements from 3D models, it is imperative to report the scanning and postscanning protocols employed when such measurements are conducted in a forensic setting. 相似文献
116.
传统方法很难检验追加文本内容打印变造的文件。运用图像处理软件Photoshop对追加文本内容的打印文件可疑之处的字体墨迹进行放大观察,对可疑之处字体笔画特征进行比对,对字间距、行间距进行测量比对检验,可以作出正确的检验结论。运用Photoshop软件对追加文本内容的打印文件检验具有直观、可靠的效果。 相似文献
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Chris Kotsirilos Stamatis Elntib 《The journal of forensic psychiatry & psychology》2019,30(4):706-725
In this experiment, both thermal imaging and the Concealed Information Test (CIT) methodologies were adopted, for the first time, to explore the efficacy of the thermal imaging of the thoracolumbar (T1–L3) region of the spinal column within the context of deception detection. Thirty-one participants followed a CIT-based structured interview process in a low-stakes laboratory setting whereby temperature fluctuations induced by the preganglionic neurons in the spinal column were measured with a thermal imaging camera during verbal responses to interview questions. The degree of temperature changes was then analyzed in order to determine truthfulness and deceit. Thermal imaging of the thoracolumbar region of the spinal column during sympathetic activation was effective in determining truthful responses with an accuracy rate of 91.9% and deceitful responses with an accuracy rate of 71.0%. Current findings support the potential use of temperature fluctuations of preganglionic neuron sites in the thoracolumbar section for lie-detection purposes. 相似文献
119.
Waltraud Baier M.Sc. Jason M. Warnett Ph.D. Mark Payne M.B.A. Mark A. Williams Ph.D. 《Journal of forensic sciences》2018,63(4):1298-1302
This case report presents one of the first reported uses of a 3D printed exhibit in an English homicide trial, in which two defendants were accused of beating their victim to death. The investigation of this crime included a micro‐CT scan of the victim's skull, which assisted the pathologist to determine the circumstances of the assault, in particular regarding the number of assault weapons and perpetrators. The scan showed two distinct injury shapes, suggesting the use of either two weapons or a single weapon with geometrically distinct surfaces. It subsequently served as the basis for a 3D print, which was shown in court in one of the first examples that 3D printed physical models have been introduced as evidence in a criminal trial in the United Kingdom. This paper presents the decision‐making process of whether to use 3D printed evidence or not. 相似文献
120.
Laser scanning technology is increasingly being used in forensic anthropological research to obtain virtual data for archival purposes and post hoc measurement collection. This research compared the measurement accuracy of two laser scanners—the FARO Focus3D 330X and the FARO Freestyle3D—against traditionally obtained (i.e., by hand) control data (N = 454). Skeletal data were collected to address a novel question: the ability of laser scanning technology to produce measurements useful for biological characteristic estimation, such as sex and stature. Results indicate that both devices produced measurements very similar to control (c. 3‐mm average absolute error), but also illuminate a tendency to under‐measure. Despite these findings, the virtual data produced sex and stature estimates that varied little from control‐produced estimates, signifying the usefulness of virtual data for preliminary biological identification when the skeletal elements are no longer available for physical analysis. 相似文献