全文获取类型
收费全文 | 870篇 |
免费 | 9篇 |
专业分类
各国政治 | 77篇 |
工人农民 | 23篇 |
世界政治 | 103篇 |
外交国际关系 | 44篇 |
法律 | 517篇 |
中国共产党 | 1篇 |
中国政治 | 4篇 |
政治理论 | 99篇 |
综合类 | 11篇 |
出版年
2024年 | 3篇 |
2023年 | 26篇 |
2022年 | 10篇 |
2021年 | 24篇 |
2020年 | 40篇 |
2019年 | 39篇 |
2018年 | 48篇 |
2017年 | 52篇 |
2016年 | 56篇 |
2015年 | 30篇 |
2014年 | 37篇 |
2013年 | 166篇 |
2012年 | 45篇 |
2011年 | 23篇 |
2010年 | 25篇 |
2009年 | 36篇 |
2008年 | 34篇 |
2007年 | 37篇 |
2006年 | 20篇 |
2005年 | 10篇 |
2004年 | 18篇 |
2003年 | 18篇 |
2002年 | 15篇 |
2001年 | 12篇 |
2000年 | 12篇 |
1999年 | 10篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
排序方式: 共有879条查询结果,搜索用时 15 毫秒
161.
气相色谱-串联质谱法分析尿和血中除草剂百草枯 总被引:1,自引:1,他引:0
目的建立尿和血中百草枯的离子交换固相萃取-气相色谱-串联质谱分析方法。方法尿样加内标乙基百草枯,用732阳离子交换树脂提取;血样加内标乙基百草枯,用三氯乙酸凝聚蛋白质后取上清液用732阳离子交换树脂提取。提取物用硼氢化钠在水溶液中碱性条件下还原,还原物用有机溶剂提取进行气相色谱-串联质谱法分析。结果尿和血中百草枯的提取率分别为76%和74%,检测限分别为2ng/mL和10ng/mL,尿添加百草枯100ng/mL和血添加百草枯500ng/mL水平的回收率分别为99.6±5.6%和99.3±7.6%(Mean±CV)。结论本文建立的分析方法灵敏度高,能够满足中毒致死案件检验及临床毒物检验的需要。 相似文献
162.
目的推测氯硝安定在生物体内的主要代谢方式,检测其代谢产物。方法取5只Wistar大鼠,连续3d给每只大鼠灌胃氯硝安定(剂量分别为1、2、2mg),收集灌胃后24h内尿液;给3只大鼠各灌胃2mg氯硝安定,2h后处死,取血液和肝组织等检材;收集3名口服5mg氯硝安定的志愿者24h内尿液。分别对不同检材进行处理后,气相色谱/质谱联用(GC/MS)检测。结果在大鼠阳性尿液和志愿者阳性尿液中,均检出7-乙酰氨基氯硝安定和7-氨基氯硝基安定;在大鼠血液中,主要检出氯硝安定和7-氨基氯硝基安定;在大鼠肝组织中,主要检出7-乙酰氨基氯硝安定,还有少量7-氨基氯硝安定和氯硝安定。结论氯硝安定进入生物体后,其7位硝基被还原为氨基,氨基接着被乙酰化,形成7-氨基氯硝基安定和7-乙酰氨基氯硝安定代谢物,其中7-乙酰氨基氯硝安定为主要代谢物。 相似文献
163.
分散固相萃取法测定人体血液中曲马多含量 总被引:1,自引:1,他引:0
目的建立一种测定人体血液中曲马多含量的规范化方法。方法采取分散固相萃取,以乙腈为提取剂,用无水硫酸镁为脱水剂,应用PSA(乙二胺N丙基硅烷)和C18进行净化,在柱温:90℃保持1min,以20℃/min升至280℃,保持7min条件下进行分析。结果曲马多的浓度在2-10ug/ml范围内,质量浓度和峰面积呈线性关系,线性方程为y=1232975.3x773017.8,相关系数为0.9982,回收率在83.729/6~91.58%之间,相对偏差为3.05%。结论此方法准确、灵敏,稳定性好,且提取过程中不易出现乳化。 相似文献
164.
应用气相色谱-串联质谱(GC/MS-MS)分别采用EI/MS、PCI/MS、NCI/MS以及EI/MS-MS、NCI/MS-MS的方法分析六种有机炸药,通过不同检测方法的检测限比较,建立了适用于法庭科学的有机炸药检测方法。 相似文献
165.
Elke Raes Kristof Pil Alain G. Verstraete 《Forensic Science International Supplement Series》2009,1(1):11-14
Research on alcohol, drugs and driving can be broadly separated into experimental and epidemiological studies. Every approach has its inherent advantages and disadvantages. Experimental studies can result in an interpretation by single cause, but can only identify potential risks, and the results can sometimes be of limited value because of the use of non-realistic doses or because of the drug use history or inter-individual differences of the volunteers. Recent studies have used higher, more realistic doses and paid more attention to the combination of alcohol and drugs and have shown that the chronic use of illicit drugs can be associated with some cognitive and/or psychomotor impairment, and can lead to a decrease in driving performance even when the subject is no longer intoxicated.Epidemiological studies include roadside surveys, studies in a subset of drivers, accident risk studies, responsibility analyses, surveys and pharmaco-epidemiological studies. Between studies, results may be incomparable due to testing different populations, different kinds of samples, etc. More large-scale roadside studies are conducted now.Advances in analytical toxicology have also contributed to a better understanding of the risks associated with driving under the influence. While older studies measured the inactive metabolite THC-COOH and did not show an increased risk in cannabis-positive drivers, more recent studies measured the active THC in blood and did show a concentration dependent increase in crash risk. The use of LC–MS/MS has allowed more broad-range screening as this technique can measure many different drugs in a small sample volume. While some older studies used saliva but had many analytical problems (including an insufficient sample volume in up to a third of the cases), newer methods of saliva sampling and analysis give better results. The use of saliva for roadside surveys allows non-invasive sampling, but the lack of correlation with the concentrations in blood makes interpretation of results difficult.The results of both epidemiological and experimental studies should be combined to obtain a good estimate of the impact of certain drugs on driving performance and accident risk. In 2006–07 a committee of international experts drafted guidelines for future research into drugs and driving. These have been taken on board by the DRUID project, a large-scale EU funded project on driving under the influence of drugs, alcohol and medicines. 相似文献
166.
Kintz P Villain M Vallet E Etter M Salquebre G Cirimele V 《Forensic science international》2008,176(1):87-90
Ethyl glucuronide (EtG) is a minor metabolite of ethanol that can be detected in hair. In some specific situations, head hair can be missing, and therefore, alternative anatomical locations of hair are of interest. In this study, paired hair specimens (head hair and pubic hair) from eight social drinkers were analyzed for EtG. Each sample was decontaminated by two dichloromethane bathes (5 ml) for 2 min. After cutting into small pieces, about 50 mg of hair was incubated in 2 ml water in the presence of 10 ng of EtG-d5, used as internal standard and submitted to ultra-sonication for 2 h. The aqueous phase was extracted by SPE using Oasis MAX columns. The hair extract was separated on an ACQUITY BEH HILIC column using a gradient of acetonitrile and formate buffer. Detection was based on two daughter ions: transitions m/z 221-85 and 75 and m/z 226-75 for EtG and the IS, respectively. This laboratory is using a positive cut-off at 50 pg/mg. All eight head hair specimens were negative for EtG at a limit of quantitation fixed at 10 pg/mg. Surprisingly, EtG was identified at high concentrations in pubic hair, in the range 12-1370 pg/mg. It appears, therefore, that it is not possible to document the drinking status of a subject by simply switching from head hair to pubic hair. 相似文献
167.
Two groups were selected from the remainder of hair samples that had been tested for drugs at TrichoTech for medico-legal cases: samples that tested negative (drug-negative group; N=42, age 33.4+/-7.2 years) and samples that tested positive for drugs (drug-positive group; N=57, age 32.5+/-8.8 years). A rapid, simple method to detect the ethanol metabolite, ethyl glucuronide (EtG) in hair has been developed. The hair samples were sectioned, and then submitted to overnight sonication in water. Samples then underwent SPE using anion exchange cartridges, followed by derivatisation with N,O-bis[trimethylsilyl]trifluoroacetamide (BSTFA), before confirmation by GC-MS/MS. The assay produced excellent linearity and sensitivity over the calibration range 0.02-1.0 ng/mg, assuming a 10 mg hair sample. The mean age of the two groups was not statistically different (p=0.575, Student t-test), indicating a homogeneous group. Twelve of the 57 (21.0%) hair samples of the drug-positive group tested positive for EtG, and 17 of the 42 (40.5%) hair samples of the drug-negative group tested positive for EtG. The mean concentration of EtG in the drug-positive group was 0.011 ng/mg compared to 0.107 ng/mg in the drug-negative group. When the full results of this study were subjected to statistical analysis it was shown that EtG levels in the drug-negative group were statistically higher than those found in the drug-positive group (p<0.05). This preliminary finding may be of use in the study of addiction and adds valuable data to previous studies regarding the use of EtG as a valuable marker for alcohol levels in hair. 相似文献
168.
169.
体液中常见滥用药物的系统筛选分析 总被引:6,自引:1,他引:5
本文建立了体液中常见滥用药物的筛选分析体系.尿液或血液经固相萃取(SPE)或液提取(LLE)后,直接用GC/NPD分析或经TFA、BSTFA衍生化后用GC/MS分析.方法适用于同时分析甲基苯丙胺、MDMA、度冷丁、去甲度冷丁、曲马多、美沙酮、EDDP、可卡因、苯甲酰芽子碱、可待因、安定、氯丙嗪、吗啡、单乙酰吗啡等十四种常见滥用药物及代谢物.SPE法和LLE法回收率分别为66~102%和50~86%,最低检出限为2-5ng/ml尿.涉毒案件的鉴定应用表明该分析方法简便、快速、可靠. 相似文献
170.
ABSTRACTThis article analyses two confronting narratives authored by Ukrainian and Russian bloggers who reported the Dutch referendum held on 6 March 2016, and discussed Dutch citizens’ referendum vote on the Ukraine–EU Association Agreement. The considered narratives, addressed to the Ukrainian and Russian audiences respectively, are viewed as strategic because they specifically portray political actors of the referendum “drama” – the Netherlands, the European Union (EU), Ukraine and Russia. These actors are significant participants of European international relations, and their perceptions of one another are important for European security at the present time of critical diplomacy. In this paper, information about the DUTCH REFERENDUM obtained from the new media texts is regarded as a narrative-based political concept (NBPC). It is argued that this concept has different versions, or images that reflect the narrators’ biased perceptions imposed upon the public. Identification and comparison of such images require a particular methodology. Therefore, the objective of this paper is two-fold: to expose the two confronting versions of a strategically relevant political image, and to develop an authentic, interdisciplinary methodology for its analysis. The proposed methodology is informed by the ontology theory employed in cognitive science and cognitive linguistics. 相似文献