全文获取类型
收费全文 | 949篇 |
免费 | 47篇 |
专业分类
各国政治 | 113篇 |
工人农民 | 56篇 |
世界政治 | 110篇 |
外交国际关系 | 52篇 |
法律 | 424篇 |
中国政治 | 27篇 |
政治理论 | 198篇 |
综合类 | 16篇 |
出版年
2023年 | 6篇 |
2022年 | 8篇 |
2021年 | 15篇 |
2020年 | 16篇 |
2019年 | 34篇 |
2018年 | 42篇 |
2017年 | 46篇 |
2016年 | 48篇 |
2015年 | 25篇 |
2014年 | 33篇 |
2013年 | 191篇 |
2012年 | 22篇 |
2011年 | 35篇 |
2010年 | 22篇 |
2009年 | 23篇 |
2008年 | 32篇 |
2007年 | 33篇 |
2006年 | 33篇 |
2005年 | 19篇 |
2004年 | 20篇 |
2003年 | 15篇 |
2002年 | 28篇 |
2001年 | 13篇 |
2000年 | 18篇 |
1999年 | 15篇 |
1998年 | 13篇 |
1997年 | 6篇 |
1996年 | 12篇 |
1995年 | 9篇 |
1994年 | 14篇 |
1993年 | 5篇 |
1992年 | 14篇 |
1991年 | 6篇 |
1990年 | 11篇 |
1989年 | 8篇 |
1988年 | 4篇 |
1987年 | 10篇 |
1986年 | 5篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1983年 | 9篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1979年 | 6篇 |
1978年 | 8篇 |
1977年 | 4篇 |
1975年 | 5篇 |
1972年 | 5篇 |
1966年 | 3篇 |
排序方式: 共有996条查询结果,搜索用时 15 毫秒
111.
112.
113.
Drug screening through urinalysis is a widely accepted tool for rapid detection of potential drug use at a relatively low cost. It is, therefore, a potentially useful method for detecting and monitoring drug use in a variety of contexts such as the criminal justice system, pre-employment screening and a variety of treatment centers. This article explores the efficacy of two commercially available drug-screening assays: Online KIMS assay (Roche) and EMIT II assays. First, we evaluate the sensitivity and specificity of two immunoassays. A total of 738 urine samples were collected among adult arrestee populations from Chicago, New Orleans and Seattle through the Arrestee Drug Abuse Monitoring (ADAM) program. Partial samples were split within one laboratory and analyzed by both enzymes multiplied immunoassay technique (EMIT) II and kinetic interaction of microparticle in solution (KIMS) assays for a 10-drug panel (amphetamine, barbiturates, benzodiazepines, marijuana, cocaine, methadone, methaqualone, opiate, phencyclidine and propoxyphene). Gas chromatography-mass spectrometry (GC-MS) was used as a confirmation method for all positives from either EMIT II or KIMS for all experiments. Second, the paper examines whether using different testing laboratories plays a role in the final results. The same experiments were repeated at two different testing locations: one in California and one in London and England. Third, the paper studies whether drug testing results vary between two laboratories when each of them had used their own routine screening method: the Forensic Science Service (FSS) at Birmingham, United Kingdom with KIMS assay and Medscreen Limited at London, United Kingdom with EMIT II. In summary, both EMIT II and KIMS assays generate fairly consistent results. The concordance rate against each of the 10 drugs tested is relatively high (97.4-100%). The discrepancies, in most cases, occurred at drug concentrations near the cut-off levels. There were more discrepant results between two laboratories compared to when specimens were analyzed at the same laboratory using two different assays. 相似文献
114.
Mura P Chatelain C Dumestre V Gaulier JM Ghysel MH Lacroix C Kergueris MF Lhermitte M Moulsma M Pépin G Vincent F Kintz P 《Forensic science international》2006,160(2-3):168-172
A collaborative study was conducted in France in order to determine the prevalence of cannabinoids, opiates, cocaine metabolites and amphetamines in blood samples from drivers killed in road accidents in 2003 and 2004 and to compare these values with those of a previous study performed during the period 2000-2001 involving 900 drivers. Blood samples were provided from 2003 under 30-year-old drivers, killed in a traffic accident. Drugs of abuse were determined by gas chromatography-mass spectrometry using the same analytical procedures in all the 12 laboratories. The most frequently observed compounds were by far cannabinoids, that tested positive in 39.6% of the total number of samples. Delta9 tetrahydrocannabinol (THC), the most active of the principle constituents in marijuana (cannabis sativa), was detected in the blood of 28.9% drivers and was the single drug of abuse in 80.2% of the positive cases. It was associated with amphetamines in 7.4% and with opiates and cocaine in 1.9 and 4.8%, respectively. Amphetamines were present in 3.1% of the total number of samples, cocaine metabolites in 3.0% and opiates in 3.5%. When comparing these results with those of a previous study performed 3 years before, a significant increase is observed for THC (28.9% versus 16.9%), cocaine metabolites (3.0% versus 0.2%) and amphetamines (3.1% versus 1.4%). This study demonstrates the critical necessity of implementing in France as soon as possible systematical roadside testing for drugs of abuse. 相似文献
115.
Stability of Delta(9)-tetrahydrocannabinol (THC) in oral fluid using the Quantisal collection device
Moore C Vincent M Rana S Coulter C Agrawal A Soares J 《Forensic science international》2006,164(2-3):126-130
This article details the stability of Delta(9)-tetrahydrocannabinol (THC) in oral fluid during collection, extraction and storage. Oral fluid is being increasingly used as the specimen of choice for the detection of drug use in various applications. Studies to determine the extraction efficiency of THC from the collection buffer and stability under various laboratory storage conditions were carried out. THC was extracted from the collection pad and buffer with an average efficiency over 80% and was stable in Quantisal oral fluid extraction buffer when stored at refrigerated temperatures. Fluorescent lighting caused THC losses of over 50%, however the presence of the pad reduced the loss. In the dark, the loss of THC at room temperature was approximately 20% over 14 days. When stored with the serum separators in place, THC losses were significant. After 3 days, THC concentration was reduced by almost 30%, and after 14 days, 60% of the drug was lost and the losses were not concentration dependent. 相似文献
116.
A rapid urinalysis system based on SPE-LC-MS/MS with an in-house post-analysis data management system has been developed for the simultaneous identification and semi-quantitation of opiates (morphine, codeine), methadone, amphetamines (amphetamine, methylamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA) and 3,4-methylenedioxymethamphetamine (MDMA)), 11-benzodiazepines or their metabolites and ketamine. The urine samples are subjected to automated solid phase extraction prior to analysis by LC-MS (Finnigan Surveyor LC connected to a Finnigan LCQ Advantage) fitted with an Alltech Rocket Platinum EPS C-18 column. With a single point calibration at the cut-off concentration for each analyte, simultaneous identification and semi-quantitation for the above mentioned drugs can be achieved in a 10 min run per urine sample. A computer macro-program package was developed to automatically retrieve appropriate data from the analytical data files, compare results with preset values (such as cut-off concentrations, MS matching scores) of each drug being analyzed and generate user-defined Excel reports to indicate all positive and negative results in batch-wise manner for ease of checking. The final analytical results are automatically copied into an Access database for report generation purposes. Through the use of automation in sample preparation, simultaneous identification and semi-quantitation by LC-MS/MS and a tailored made post-analysis data management system, this new urinalysis system significantly improves the quality of results, reduces the post-data treatment time, error due to data transfer and is suitable for high-throughput laboratory in batch-wise operation. 相似文献
117.
Robinson N Castella V Saudan C Sottas PE Schweizer C Dimo-Simonin N Mangin P Saugy M 《Forensic science international》2006,163(1-2):148-151
The case of seven urine samples collected for anti-doping purposes during a cycling stage race with moderately elevated testosterone and epitestosterone ratio (T/E) is reported. The very low probability of having all seven urine samples with such similar elevated T/E ratio (from 3.2 to 4.7) was very suspicious. Different pattern classification tools were tested to categorize the most similar steroid profiles, but none of the models enabled a clear classification of the different urine samples. Subsequently, genetic profiling of all urine samples was performed and demonstrated that three of the seven samples were collected from the same cyclist. Finally, the International Federation confirmed DNA profiling results. This suggests that urinary steroid data using several methodologies are not appropriate for identification purposes and to an extent not unique to individuals. 相似文献
118.
Ronald S. Bond John E. Kwoka Jr. John J. Phelan Ira Taylor 《Law and human behavior》1983,7(2-3):219-234
This study provides an empirical analysis of the effects of advertising and commercial practice on the price and quality of optometrists' services. Data were collected by actually purchasing eye examinations and eyeglasses from optometrists in cities with and without restrictions on advertising and commercial practice. Analysis of the data supports the view that advertising and commercial practice lower prices but do not lower the quality of professional care available in the market. The implications of these findings are discussed. 相似文献
119.
120.