全文获取类型
收费全文 | 9379篇 |
免费 | 298篇 |
专业分类
各国政治 | 513篇 |
工人农民 | 311篇 |
世界政治 | 757篇 |
外交国际关系 | 419篇 |
法律 | 5147篇 |
中国共产党 | 1篇 |
中国政治 | 75篇 |
政治理论 | 2337篇 |
综合类 | 117篇 |
出版年
2020年 | 111篇 |
2019年 | 166篇 |
2018年 | 223篇 |
2017年 | 217篇 |
2016年 | 223篇 |
2015年 | 174篇 |
2014年 | 215篇 |
2013年 | 1114篇 |
2012年 | 247篇 |
2011年 | 232篇 |
2010年 | 217篇 |
2009年 | 235篇 |
2008年 | 240篇 |
2007年 | 257篇 |
2006年 | 260篇 |
2005年 | 227篇 |
2004年 | 237篇 |
2003年 | 238篇 |
2002年 | 226篇 |
2001年 | 266篇 |
2000年 | 230篇 |
1999年 | 204篇 |
1998年 | 138篇 |
1997年 | 128篇 |
1996年 | 108篇 |
1995年 | 112篇 |
1994年 | 112篇 |
1993年 | 122篇 |
1992年 | 153篇 |
1991年 | 179篇 |
1990年 | 148篇 |
1989年 | 178篇 |
1988年 | 149篇 |
1987年 | 179篇 |
1986年 | 165篇 |
1985年 | 179篇 |
1984年 | 168篇 |
1983年 | 166篇 |
1982年 | 132篇 |
1981年 | 119篇 |
1980年 | 111篇 |
1979年 | 107篇 |
1978年 | 90篇 |
1977年 | 72篇 |
1976年 | 76篇 |
1975年 | 76篇 |
1974年 | 82篇 |
1973年 | 82篇 |
1972年 | 60篇 |
1969年 | 62篇 |
排序方式: 共有9677条查询结果,搜索用时 31 毫秒
891.
892.
893.
A Bargaining Model of Holdouts and Takings 总被引:1,自引:0,他引:1
The holdout problem is commonly cited as the justification foreminent domain, but the nature of the problem is not well understood.This article models the holdout problem in a bargaining framework,where a developer seeks to acquire several parcels of land fora large-scale development. We show that in the absence of eminentdomain, holdouts are a significant threat, resulting in costlydelay. However, if the developer has the power to use eminentdomain to acquire the land from holdouts, all sellers will bargain,thus avoiding delay. An offsetting cost is that owners may negotiateprices below their true value, possibly resulting in excessivetransfer of land to the developer. 相似文献
894.
895.
A range of fibre samples was measured using J&M MSP400 and J&M MSP800 microspectrophotometers across the visible and UV/visible wavelength ranges respectively. The first derivative of the absorbance spectra was then calculated and studied. When the absorbance spectra produced for some samples were broad and featureless, the first derivative spectra provided more points of comparison that facilitated discrimination. For many of the samples, calculating the first derivative did not result in any additional discrimination due to the high number of points of comparison present in the absorbance spectra. However, for the samples that exhibited a high level of intra-sample colour variation (e.g. through uneven dye uptake common in cotton and wool, etc.), which was evident in the absorbance spectra, the associated first derivative spectra highlighted this variation between the fibres and could potentially have resulted in false exclusions. The results show that whilst calculating first derivative can be a useful aid in the comparison of spectra, a high degree of caution is required when applying this method to fibres which exhibit a large intra-sample variation in colour. 相似文献
896.
Brett A. Schweers Jennifer Old P.W. Boonlayangoor Karl A. Reich 《Forensic Science International: Genetics Supplement Series》2008,2(3):243-247
Human blood is the body fluid most commonly encountered at crime scenes, and blood detection may aid investigators in reconstructing what occurred during a crime. In addition, blood detection can help determine which items of evidence should be processed for DNA-STR testing. Unfortunately, many common substances can cause red-brown stains that resemble blood. Furthermore, many current human blood detection methods are presumptive and prone to false positive results. Here, the developmental validation of a new blood identification test, Rapid Stain Identification™-Blood (RSID™-Blood), is described. RSID™-Blood utilizes two anti-glycophorin A (red blood cell membrane specific protein) monoclonal antibodies in a lateral flow strip test format to detect human blood. We present evidence demonstrating that this test is accurate, reproducible, easy to use, and highly specific for human blood. Importantly, RSID™-Blood does not cross-react with ferret, skunk, or primate blood and exhibits no high-dose hook effect. Also, we describe studies on the sensitivity, body fluid specificity, and species specificity of RSID™-Blood. In addition, we show that the test can detect blood from a variety of forensic exhibits prior to processing for DNA-STR analysis. In conclusion, we suggest that RSID™-Blood is effective and useful for the detection of human blood on forensic exhibits, and offers improved blood detection when compared to other currently used methods. 相似文献
897.
W F McCormick J H Stewart H Greene 《The American journal of forensic medicine and pathology》1991,12(2):175-181
Measurement of clavicular length and circumference, and computation of clavicular robustness and length-circumference product from 724 autopsied adults of known age, sex, and body length between the ages of 15 and 96 years produced useful sex-predictive values. This predominantly North American white population contained 560 males and 164 females with intact, nondeformed clavicles. Clavicle length and circumference and particularly their product have been found useful in sexing, but robustness as a single trait has not. Despite a significant overlap of male and female values, the use of single cutoff values allowed correct sex assignment of up to 93% of the entire study population, including 94% of males and 89% of females. The ratios of body length to clavicle circumference and to clavicle length are on average greater in women than in men. The former ratio yields male predictive values greater than 95% for those individuals with ratios falling below the cutoff value of 43, whereas the latter ratio is a relatively poor sex predictor. 相似文献
898.
899.
Peak blood-ethanol concentration and the time of its occurrence after rapid drinking on an empty stomach 总被引:2,自引:0,他引:2
Healthy men, 20 to 60 years old, drank a moderate dose of ethanol in the morning after an overnight fast. They consumed either neat whisky in amounts corresponding to 0.34, 0.51, 0.68, 0.85, or 1.02 g of ethanol per kilogram of body weight or 0.80 g/kg ethanol solvent diluted with orange juice. The peak blood-ethanol concentration (BEC) increased with the dose administered, but the time required to reach the peak was not markedly influenced over the range of doses studied. At a dose of 0.68 g/kg, the peak BEC ranged from 52 to 136 mg/dL (N = 83), and slow absorption (a late-occurring peak) produced a lower peak BEC. The peak BEC was reached between 0 and 45 min for 77% of the subjects (N = 152) and between 0 and 75 min for 97% of them. The time of peaking in venous blood occurred, on average, 10 min later than in capillary (fingertip) blood although the peak BEC was not appreciably different; the mean venous BEC was 97.0 mg/dL (range, 76 to 112 mg/dL), and the mean capillary BEC was 99.6 mg/dL (range, 75 to 123 mg/dL). When subjects drank 0.80 g/kg ethanol diluted with orange juice over 30 min, the average BEC increment between the end of drinking and the peak was 33 mg/dL (range, 0 to 58 mg/dL). The rate of absorption of ethanol was 1.78 mg/dL/min (range, 0.52 to 4.8 mg/dL/min), and the peak BEC occurred within 60 min after the end of drinking in 92% of the trials. The largest BEC increment (mean, 21 mg/dL; range, 0 to 44 mg/dL) was seen during the first 15 min after the drinking period. 相似文献
900.
J G Prichard P D Kossoris R A Leibovitch L D Robertson F W Lovell 《Journal of forensic sciences》1986,31(1):301-306
Bites of Trombiculid mites implicated a suspect during a homicide investigation. Clinical documentation of the bites, correlation with entomological studies, and submission of evidence at trial are reported. Insects that have a discrete geographic distribution and leave bites of a characteristic nature may have important forensic science implications. 相似文献