首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   163篇
  免费   7篇
各国政治   7篇
工人农民   17篇
世界政治   17篇
外交国际关系   8篇
法律   99篇
中国政治   1篇
政治理论   20篇
综合类   1篇
  2024年   8篇
  2023年   46篇
  2021年   10篇
  2020年   5篇
  2019年   5篇
  2018年   8篇
  2017年   5篇
  2016年   8篇
  2015年   3篇
  2014年   3篇
  2013年   20篇
  2012年   4篇
  2011年   6篇
  2010年   3篇
  2009年   2篇
  2008年   4篇
  2007年   6篇
  2006年   4篇
  2005年   2篇
  2004年   2篇
  2003年   3篇
  2000年   1篇
  1999年   1篇
  1998年   2篇
  1995年   1篇
  1994年   1篇
  1993年   2篇
  1992年   1篇
  1989年   1篇
  1987年   1篇
  1986年   1篇
  1980年   1篇
排序方式: 共有170条查询结果,搜索用时 609 毫秒
31.
While canines are most commonly trained to detect traditional explosives, such as nitroaromatics and smokeless powders, homemade explosives (HMEs), such as fuel–oxidizer mixtures, are arguably a greater threat. As such, it is imperative that canines are sufficiently trained in the detection of such HMEs. The training aid delivery device (TADD) is a primary containment device that has been used to house HMEs and HME components for canine detection training purposes. This research assesses the odor release from HME components, ammonium nitrate (AN), urea nitrate (UN), and potassium chlorate (PC), housed in TADDs. Canine odor recognition tests (ORTs) were used with analytical data to determine the detectability of TADDs containing AN, UN, or PC. Headspace analysis by gas chromatography/mass spectrometry (GC/MS) with solid-phase microextraction (SPME) or online cryotrapping were used to measure ammonia or chlorine, as well as other unwanted odorants, emanating from bulk AN, UN, and PC in TADDs over 28 weeks. The analytical data showed variation in the amount of ammonia and chlorine over time, with ammonia from AN and UN decreasing slowly over time and the abundance of chlorine from PC TADDs dependent on the frequency of exposure to ambient air. Even with these variations in odor abundance, canines previously trained to detect bulk explosive HME components were able to detect all three targets in glass and plastic TADDs for at least 18 months after loading. Detection proficiency ranged from 64% to 100% and was not found to be dependent on either age of material.  相似文献   
32.
The storage and use of explosives is regulated at the state and federal level, with a particular focus on physical security and rigorous accounting of the explosive inventory. For those working with explosives for the training and testing of explosive-detecting canines, cross-contamination is an important concern. Hence, explosives intended for use with canine teams must be placed into secondary storage containers that are new, clean, and airtight. A variety of containers meet these requirements and include screw-top glass jars (e.g., mason jars). However, an additional need from the explosive-detecting canine community is secondary containers that can also be used as training aids whereby the volatiles emitted by explosives are emitted in a predictable and stable manner. Currently, a generally accepted method for the storage of explosives and controlled emission of explosive vapor for canine detection does not exist. Ideally, such containers should allow odor to escape from the training aid but block external contaminates such as particulates or other volatiles. One method in use places the explosive inside a permeable cotton bag when in use for training and then stores the cotton bag inside an impermeable nylon bag for long-term storage. This paper describes the testing of an odor permeable membrane device (OPMD) as a new way to store and deploy training aids. We measured the evaporation rate and flux of various liquid explosives and volatile compounds that have been identified in the headspace of actual explosives. OPMDs were used in addition to traditional storage containers to monitor the contamination and degradation of 14 explosives used as canine training aids. Explosives were stored individually using traditional storage bags or inside an OPMD at two locations, one of which actively used the training aids. Samples from each storage type at both locations were collected at 0, 3, 6, and 9 months and analyzed using Fourier Transform Infrared (FTIR) Spectroscopy and Gas Chromatography–Mass Spectrometry (GC–MS) with Solid-Phase Microextraction (SPME). FTIR analyses showed no signs of degradation. GC–MS identified cross-contamination from ethylene glycol dinitrate (EGDN) and/or 2,3-dimethyl-2,3-dinitrobutane (DMNB) across almost all samples regardless of storage condition. The contamination was found to be higher among training aids that were stored in traditional ways and that were in active use by canine teams.  相似文献   
33.
This work presents a data survey regarding the qualitative chemical analysis of drugs seized by the Police in the state of Minas Gerais between July 2017 and June 2022, including an evaluation of labeling of 265 samples of anabolic androgenic steroids (AAS) seized in 2020. The Active Pharmaceutical Ingredients (API) present in the samples were identified through chemical analysis and classified by system Anatomical Therapeutic Chemical (ATC) methods. Analysis of the labeling information for 265 samples of AAS followed the guidance of legislation RDC 71 (2009) from ANVISA. For this study 6355 seized pharmaceuticals underwent qualitative chemical analysis that corresponded to 7739 APIs successfully identified and classified. Among the components studied AAS, psychostimulants, anesthetics, and analgesics were the most commonly examined. AAS seized and tested increased by over 100% and for the majority of the samples analyzed were found to not match the labeling on the packaging. In the meantime, anti-obesity drugs presented a prominent increase of 400% from 2020/1 to 2021/2, during covid-19 quarantine. Seized pharmaceuticals and tests can support information in the planning of public health and safety policies.  相似文献   
34.
Human hairs are one of the most commonly encountered items of trace evidence. Currently, conventional methods for hair analysis include microscopic comparison and DNA analysis (nuclear and mitochondrial). Each approach has its own drawbacks. Hair proteins are stable and offer an alternative to DNA testing, as demonstrated with proteomics for distinguishing humans. However, proteomics is complicated and requires identifying peptides to remain intact following harsh sample preparation methods. Alternatively, the actual amino acid content of a hair sample may also offer important identifying information and actually requires proteins and peptides to be broken down completely rather than remaining intact. This study evaluated the discriminating power of using hair amino acid ratios to differentiate hair samples from 10 unrelated individuals with dark colored hair. Hair proteins were digested, derivatized, and analyzed using gas chromatography–mass spectrometry. Amino acid ratios were calculated for each individual and comparisons using ANOVA and post-hoc pairwise t-test with Bonferroni correction were made with amino acid ratios for individuals. Overall, out of the 45 possible pairwise comparisons between all hair samples, 38 (84%) were differentiable. Out of the 36 possible pairwise comparisons between brown haired individuals, 32 (89%) were considered differentiable using univariate statistics. Multivariate statistics were also attempted but, overall, univariate models were sufficient for exclusionary purposes. These results indicate that amino acid ratio analysis can potentially be used as an exclusionary method using hair if DNA analysis cannot be performed, or to corroborate conclusions made following microscopic analysis.  相似文献   
35.
36.
Hand–foot syndrome, a chemotherapy‐induced cutaneous toxicity, can cause an alteration in fingerprints causing a setback for cancer patients due to the occurrence of false rejections. A colon cancer patient was fingerprinted after not having been able to use fingerprint recognition devices after 6 months of adjuvant chemotherapy. The fingerprint images were digitally processed to improve fingerprint definition without altering the papillary design. No evidence of skin toxicity was present. Two months later, the situation returned to normal. The fingerprint evaluation conducted on 15 identification points highlighted the quantitative and qualitative fingerprint alteration details detected after the end of chemotherapy and 2 months later. Fingerprint alteration during chemotherapy has been reported, but to our knowledge, this particular case is the first ever reported without evident clinical signs. Alternative fingerprint identification methods as well as improved biometric identification systems are needed in case of unexpected situations.  相似文献   
37.
Three studies used the symbolic theory of history and identity to examine the impact of social representations of the 1986 EDSA I ??People Power?? revolution on participation in subsequent protest social movements in the Philippines. Study 1 found that in 4 state universities scattered across the archipelago of the Philippines, the first EDSA revolution was nominated as the most important event in Filipino history, and formed part of a narrative moving from authoritarian to democratic rule. Study 2 employed a mixed convenience sample of university students and adults to show that a measure of historical fatalism, or cynicism about the ability of EDSA I to produce lasting social change together with low identification with the social movement predicted lack of passive behavioral participation in the social movement that overthrew President Estrada in the EDSA II revolution. The importance of removing Estrada (derived from an expectancy?Cvalue/cost?C-benefit analysis formulation) was the best predictor of active behavioral participation. Study 3 showed that historical fatalism was the best predictor of behavioral intentions to actively participate in an attempt to overthrow Estrada??s successor President Arroyo, whereas anger was the best predictor of passive behavioral intentions among university students. Results suggest an exhaustion of goodwill from Filipinos, who no longer believe that People Power can force positive change against endemic corruption in national governance.  相似文献   
38.
Sevoflurane concentrations in blood, brain, and lung were measured in an individual apparently dying from sevoflurane inhalation. Sevoflurane is a volatile nonflammable fluorinated methyl isopropyl ether inhaled anesthetic, chemically related to desflurane and isoflurane. The incidence of abuse of sevoflurane is lower than that of other drugs of abuse possibly due to its inaccessibility to the general public and less pleasurable and addicting effects. The dead subject was an anesthetist found prone in bed holding an empty bottle of sevoflurane (Ultane). Serum, urine, and liver were screened for numerous drugs and metabolites using enzyme immunoassays and gas chromatography-mass spectrometry. Analysis did not reveal presence of any drug, including ethanol, other than sevoflurane. Sevoflurane was determined by headspace gas chromatography and revealed concentrations of 15 microg/mL in blood and 130 mg/kg in brain and lung. Autopsy revealed pulmonary edema and frothing in the lung, pathological findings associated with death by sevoflurane or hypoxia. The cause of death was ruled as sevoflurane toxicity and the manner of death as accident.  相似文献   
39.
The accurate quantification of target DNA is an important step in the short tandem repeat analysis of forensic biological samples. By utilizing quantification data to control the amount of template DNA in the polymerase chain reaction (PCR), forensic scientists can optimize testing and minimize the consumption of limited samples. The ability to identify and quantify target DNA in mixed-species samples is crucial when it may be overwhelmed by nontarget DNA, as in cases of dog attack. We evaluated two quantitative real-time PCR assays for dynamic range, species specificity, and inhibition by humic acid. While both assays proved to be highly sensitive and discriminating, the Melanocortin-1 Receptor (MC1R) gene Taqman assay had the advantages of a shorter run time, greater efficiency, and safer reagents. In its application to forensic casework, the MC1R assay has been advantageous for quantifying dog DNA in a variety of mixed-species samples and facilitating the successful profiling of individual dogs.  相似文献   
40.
Trace DNA analysis is a significant part of a forensic laboratory's workload. Knowing optimal sampling strategies and item success rates for particular item types can assist in evidence selection and examination processes and shorten turnaround times. In this study, forensic short tandem repeat (STR) casework results were reviewed to determine how often STR profiles suitable for comparison were obtained from “handler” and “wearer” areas of 764 items commonly submitted for examination. One hundred and fifty‐five (155) items obtained from volunteers were also sampled. Items were analyzed for best sampling location and strategy. For casework items, headwear and gloves provided the highest success rates. Experimentally, eyeglasses and earphones, T‐shirts, fabric gloves and watches provided the highest success rates. Eyeglasses and latex gloves provided optimal results if the entire surfaces were swabbed. In general, at least 10%, and up to 88% of all trace DNA analyses resulted in suitable STR profiles for comparison.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号