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31.
Devesh Kapur Centre for Advanced Study of India, University of Pennsylvania, 3600 Market Street, Suite 560, Philadelphia, PA 19104 e-mail: dkapur{at}sas.upenn.edu e-mail: herrera{at}fas.harvard.edu (corresponding author) This paper examines the construction and use of data sets inpolitical science. We focus on three interrelated questions:How might we assess data quality? What factors shape data quality?and How can these factors be addressed to improve data quality?We first outline some problems with existing data set quality,including issues of validity, coverage, and accuracy, and wediscuss some ways of identifying problems as well as some consequencesof data quality problems. The core of the paper addresses thesecond question by analyzing the incentives and capabilitiesfacing four key actors in a data supply chain: respondents,data collection agencies (including state bureaucracies andprivate organizations), international organizations, and finally,academic scholars. We conclude by making some suggestions forimproving the use and construction of data sets. Authors' note: For generous comments at many stages in the paper,the authors would like to thank Dawn Brancati, Bear Braumoeller,Kanchan Chandra, Jorge Dominguez, Errol D'Souza, Richard Grossman,Ana Grzymala-Busse, Andrew Kydd, David Laitin, Daniel Posner,Jasjeet Sekhon, Hillel Soifer, Jessica Wallack, and Steven Wilkinsonand the Comparative Politics Research Workshop at Harvard University,and the anonymous reviewers from Political Analysis. The authorstake full responsibility for any errors. An earlier versionof this paper was presented at the American Political ScienceAssociation Annual Meetings, Boston, MA, August 2002.  相似文献   
32.
A method is described for the determination of delta 9-tetrahydrocannabinol (delta 9-THC) in the saliva by the use of a combination of moving-precolumn injector and glass capillary gas chromatograph with electron capture detector (GC/ECD). There were no interfering peaks due to impurities around the peak of pentafluoropropyl derivative of delta 9-THC (delta 9-THC-PFP). This GC/ECD method was linear over the range of 5-200 ng/ml of delta 9-THC-PFP. The lower detection limit was approximately 1 ng/ml. delta 9-THC content in the saliva after experimental marihuana smoking was measured by this method. It was demonstrated that for at least 4 h after smoking the level of delta 9-THC was sufficient for detection.  相似文献   
33.
Sectional analysis of methamphetamine abuser's hair was performed by using stable-isotope dilution GC/MS method. Drug concentrations of hair shaft cut into 2-cm sections from the root side were compared with the self-reported drug histories of 11 cases and the results of experiments on monkeys. It was found that in nine of the 11 cases, the relationship between the results of sectional analysis and drug histories coincided, but the sectional analyses of two cases were not consistent with self-reported drug history. The difference in drug concentrations between the regions of scalp hair was also investigated. Our study suggests that hair analysis, especially sectional analysis, may be useful in determining past drug history even though it is not exact.  相似文献   
34.
Internationally shared basins supply 60 % of global freshwater supply, are home to about 1/3 of the world’s population, and are focal points for interstate conflict and, as importantly, cooperation. To manage these waters, states have developed a large set of formal treaties, but until now these treaties have been difficult to access and systematically assess. This paper presents and makes publicly available the assembly and organization of the largest known collection of transboundary water agreements in existence. We apply for the first time a “lineage” concept to differentiate between independent agreements and groups of legally related texts, spatially reference the texts to a global basin database, and identify agreement purposes, goals and a variety of content areas. The 688 agreements identified were signed between 1820 and 2007 and constitute 250 independent treaties which apply to 113 basins. While the scope and content varies widely, these treaties nominally govern almost 70 % of the world’s transboundary basin area. In terms of content, treaties have shifted from an earlier focus on regulation and development of water resources to the management of resources and the setting of frameworks for that management. While “traditional” issues such as hydropower, water allocation and irrigation are still important, the environment is now the most commonly mentioned issue in treaty texts. Treaties are also increasingly likely to include data and information sharing provisions, have conflict resolution mechanisms, and include mechanisms for participation beyond traditional nation-state actors. Generalizing, treaties have become more comprehensive over time, both in the issues they address and the tools they use to manage those issues cooperatively.  相似文献   
35.
A delayed drowning death case with histological findings of shock was described. The person was sustained by continuous positive-pressure respiration and died 2 days after resuscitation from drowning. The histological findings were intravascular microthrombi, hyaline bodies and fibrin thrombi in the brain, multiple megakaryocytes in the pulmonary capillaries, hyaline membranes of the lung, multiple small hyaline bodies in the liver sinusoids, and erosion of the mucous membrane of the stomach as well as histological findings of shock kidney. Drowning and systemic hypotension during resuscitation seemed to cause irreversible oxygen debt of the organs and the tissues to lead to shock.  相似文献   
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37.
To investigate the effects of very high concentrations of carbon dioxide (CO2) upon the course of respiration and circulation, dogs were allowed to breathe high concentrations of CO2 while intrathoracic pressure, blood pressure (BP) in the femoral artery, electrocardiogram and electroencephalogram readings were registered. The respiratory movements either increased just after inhalation of high concentrations of CO2 and then ceased in 1 min, or decreased and continued for a while according to the concentrations of CO2. The BP showed an initial depression, then returned to the original level, then fell again rapidly or maintained an appreciable level for a while until circulatory breakdown. In the dogs allowed to breathe the gas mixture of 80% CO2 with 20% O2, the respiratory movement ceased in 1 min, and the terminal respirations were seen with the circulatory breakdown after apnoea of several minutes. These findings showed that the cause of death in breathing high concentrations of CO2 is not hypoxia, but the CO2 poisoning.  相似文献   
38.
A 41-year-old man was accidentally exposed to carbon monoxide (CO) gas and found in a state of cardiopulmonary arrest while he took bath. After admission, he was resuscitated and underwent artificial ventilation in a comatose state and died about 19h later. Computed tomography (CT) examination disclosed bilateral low density area in the basal ganglia and the thalamus, a well-known finding in the CO intoxication. Necropsy, histological examination, DNA ladder assay gave the first line of evidence for the presence of apoptosis as well as necrosis in the human case of CO intoxication. TdT-mediated dUTP-biotin nick-end labeling (TUNEL) positive apoptotic cells were more predominant in the CA2 area than in CA1 area. There is general co-relation between the ratio of TUNEL-positive cells and the DNA laddering on the agarose gel. Basal ganglia and thalamus, which showed bilateral low density area in CT, were revealed to be severe edema. The two types of cell death occurred in the cortex, basal ganglia, hippocampus, thalamus, and cerebellum. Hypoxia caused by CO-hemoglobin formation alone cannot explain the phenomena.  相似文献   
39.
An experimental study of death in a reverse suspension.   总被引:3,自引:0,他引:3  
To investigate the course of respiration and circulation in a head-down position, 14 rabbits were set in reverse suspension. The respiratory rate increased a little, but the amplitude of the respiratory movements did not change in the beginning of the experiment. The amplitude of respiratory movements then began to reduce gradually, and toward the end of the experiment, it reduced suddenly. PaO2 increased in the beginning of the experiment and then began to decrease in accordance with the reduction of the amplitude of the respiratory movements. The blood pressure decreased with relation to the decrease of PaO2 resulting from the reduction of the amplitude of the respiratory movements. All rabbits died in 17 to 44 hours (average, 26 hours). The results suggested that the cause of death in a head-down position is due to postural asphyxia resulting from hindered respiratory movements, and that it is possible to survive for at least half a day in a head-down position.  相似文献   
40.
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