全文获取类型
收费全文 | 12668篇 |
免费 | 1301篇 |
专业分类
各国政治 | 460篇 |
工人农民 | 414篇 |
世界政治 | 945篇 |
外交国际关系 | 410篇 |
法律 | 9434篇 |
中国共产党 | 1篇 |
中国政治 | 86篇 |
政治理论 | 2139篇 |
综合类 | 80篇 |
出版年
2020年 | 367篇 |
2019年 | 372篇 |
2018年 | 416篇 |
2017年 | 498篇 |
2016年 | 515篇 |
2015年 | 459篇 |
2014年 | 454篇 |
2013年 | 1313篇 |
2012年 | 298篇 |
2011年 | 411篇 |
2010年 | 566篇 |
2009年 | 522篇 |
2008年 | 313篇 |
2007年 | 273篇 |
2006年 | 393篇 |
2005年 | 277篇 |
2004年 | 268篇 |
2003年 | 260篇 |
2002年 | 228篇 |
2001年 | 460篇 |
2000年 | 376篇 |
1999年 | 315篇 |
1998年 | 164篇 |
1997年 | 144篇 |
1996年 | 114篇 |
1995年 | 140篇 |
1994年 | 149篇 |
1993年 | 127篇 |
1992年 | 225篇 |
1991年 | 248篇 |
1990年 | 230篇 |
1989年 | 238篇 |
1988年 | 213篇 |
1987年 | 185篇 |
1986年 | 209篇 |
1985年 | 234篇 |
1984年 | 227篇 |
1983年 | 195篇 |
1982年 | 155篇 |
1981年 | 133篇 |
1980年 | 135篇 |
1979年 | 153篇 |
1978年 | 95篇 |
1977年 | 85篇 |
1976年 | 69篇 |
1975年 | 76篇 |
1974年 | 80篇 |
1973年 | 65篇 |
1972年 | 60篇 |
1971年 | 56篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
811.
Event reconstruction plays a critical role in solving physical crimes by explaining why a piece of physical evidence has certain characteristics. With digital crimes, the current focus has been on the recognition and identification of digital evidence using an object's characteristics, but not on the identification of the events that caused the characteristics. This paper examines digital event reconstruction and proposes a process model and procedure that can be used for a digital crime scene. The model has been designed so that it can apply to physical crime scenes, can support the unique aspects of a digital crime scene, and can be implemented in software to automate part of the process. We also examine the differences between physical event reconstruction and digital event reconstruction. 相似文献
812.
The New York State Convicted Offender DNA Databank is the first U.S. lab to complete an internal validation of the TrueAllele expert data review system. TrueAllele is designed to assess short tandem repeat (STR) DNA data based on several key features such as peak height, shape, area, and position relative to a standard ladder and use this information to make accurate allele calls. The software then prioritizes the allele calls based on several user-defined rules. As a result, the user need only review low-quality data. The validation of this system consisted of an extensive optimization phase and a large concordance phase. During optimization, the rule settings were tailored to minimize the amount of high-quality data viewed by the user. In the concordance phase, a large dataset was typed in parallel with the ABI software Gene Scan and Genotyper (manual review) and TrueAllele (automated review) for comparison of allele calls and sample state assignment. Only one significant difference was discovered out of 2048 samples in the concordance study. In this case, TrueAllele revealed a spike in the profile that was interpreted as a DNA peak by the analyst in Genotyper. TrueAllele was designed to focus the review on poor data and to eliminate the need for complete reanalysis technical review. This validation project proved TrueAllele to be dependable for use at the NYS Convicted Offender DNA Databank. 相似文献
813.
Armstrong A Babrauskas V Holmes DL Martin C Powell R Riggs S Young LD 《Journal of forensic sciences》2004,49(4):741-748
Tests have determined that boots or shoes of individuals at a fire scene do not transport sufficient contaminants ("tracking") through the fire scene to produce a positive laboratory result for the presence of gasoline in a fire scene that was not present at the time of the fire. Questions about the validity of forensic laboratory results have been raised on the basis that low-level gasoline residues detected in the laboratory samples could have been the result of transporting the residue by footwear contaminated from the fire scene ("tracking"). The data collected in this study establish that "tracking" does not lead to false-positive laboratory results. Canines trained and experienced in the detection of trace ignitable liquid residues were also utilized in this study. The canine results confirmed that properly trained canines show a higher sensitivity than do standard ASTM laboratory techniques for fire debris analysis. In a few cases, canines responded to contamination, but laboratory testing (which is the definitive indicator) did not produce positive results. 相似文献
814.
Gel ink pens have become a common writing instrument in the United States. Questioned document examiners often attempt to optically differentiate gel inks from each other and from other non-ballpoint ink writings (e.g., those from roller-ball pens). Since early formulations were primarily pigment-based, they do not elute when analyzed by thin-layer chromatography. However, recent gel ink formulations (i.e., within the past five years) include dye-based inks that can be easily separated. This study differentiates black gel inks using optical and chemical techniques. The techniques include: microscopy, visible and near infrared reflectance, near infrared luminescence, thin-layer chromatography (TLC), spot tests, and gas chromatography/mass spectrometry (GC/MS). As a result of this study a flow chart has been developed allowing for a systematic determination of a questioned ink. In addition, an analysis of volatile compounds found in gel inks revealed that there are some unique ingredients that may be found in gel inks that are not typically found in other non-ballpoint inks. 相似文献
815.
The pathomorphology of intoxication of alcohol surrogates is described. A high frequency rate of DIC-syndrome is shown for the condition. A majority of thrombi accumulates at places with the highest concentrations of toxic substances as well as at those places, through which poisoning substances are brought out of the body, i.e. in the liver (since toxic substances are introduced perorally) and kidneys. Thrombi were detected in all internals, including the brain, in lethal intoxication. The immediate toxic effect from methanol and from higher spirits can matter in the genesis of changes, including acute swelling and chromatolysis with subsequent cell death. Exclusively cerebral or coagulopathic-cerebral types of thanatogenesis were registered in studied case of intoxication. 相似文献
816.
Kornienko IV Vodolazhskiĭ DI Afanas'eva GV Ivanov PL 《Sudebno-meditsinskaia ekspertiza》2004,47(6):27-32
Polymorphism of mDNA D-loop central region (CR), positions 16366-0072) was studied versus hypervariable sections (HVS1), positions 16024-16365, and HVS2, positions 00073-00340, for a sample of 71 residents of the Russian Federation. Ten polymorphic positions with 56 nucleotide substitutions, 55 of which are transitions, were detect in the CR section; no insertions or deletions were found there. It was proven as possible to use the mDNA CR locus as an additional identification marker in the forensic-expert of the mDNA control region. The probability of random coincidence (RC) of haplotypes in joint typing of HVS1, HVS2 and CR made 0.0208, which is 1.4-fold less versus the same parameter for haplotypes HVS1/HVS2 (RC = 0.0284). 相似文献
817.
Previous research shows that expert testimony on eyewitness memory influences mock-juror judgments. We examined the extent to which opposing expert testimony mitigates the impact of defense-only expert testimony. Participants (N = 497) viewed a video-taped trial involving an eyewitness identification and individually rendered verdicts and evaluated the evidence and the experts. We manipulated the Foils (unbiased vs. biased) and Instructions (unbiased vs. biased) of the lineup and Expert Testimony (no expert vs. defense-only expert vs. opposing experts). Expert testimony did not significantly influence juror judgments, but the opposing expert testimony diminished the credibility of the defense expert in the eyes of the jurors. Results point to the need for further research on conditions that qualify the impact of expert testimony. 相似文献
818.
819.
Two studies examined unconscious racial stereotypes of decision makers in the juvenile justice system. Police officers (Experiment 1) and juvenile probation officers (Experiment 2) were subliminally exposed to words related to the category Black or to words neutral with respect to race. In a presumably unrelated task, officers read 2 vignettes about a hypothetical adolescent who allegedly committed either a property crime (shoplifting from a convenience store) or an interpersonal crime (assaulting a peer). The race of the offender was left unstated and the scenarios were ambiguous about the causes of the crime. Respondents rated the hypothetical offender on a number of traits (e.g., hostility and immaturity) and made judgments about culpability, expected recidivism, and deserved punishment. They also completed a self-report measure of conscious attitudes about race. As hypothesized, officers in the racial prime condition reported more negative trait ratings, greater culpability, and expected recidivism, and they endorsed harsher punishment than did officers in the neutral condition. The effects of the racial primes were not moderated by consciously held attitudes about African Americans. The implications of the findings for racial disparity in the juvenile justice system and for changing unconscious stereotypes were discussed. 相似文献
820.
Lora-Tamayo C Tena T Rodríguez A Moreno D Sancho JR Enseñat P Muela F 《Forensic science international》2004,140(2-3):195-206
A total of 137 urine samples and 46 serum samples, corresponding to 154 self-confessed designer drugs consumers in Ibiza island, were analyzed for the presence of designer drugs: amphetamine and amphetamine derivatives (methamphetamine, methylenedioxymethamphetamine (MDMA), methylenedioxyethylamphetamine (MDEA), methylenedioxyamphetamine (MDA), p-methoxymethylamphetamine (PMMA), p-methoxyamphetamine (PMA), etc.), ketamine and gamma-hydroxybutyric acid. Among this population, coming both from the forensic clinic and from the emergency room of a hospital, a total of 99 cases were found positive for some designer drug. This study shows the prevalence of methylenedioxymethamphetamine (MDMA) among designer drug users, sole or in association with other drugs. Also, the mixture of MDMA with other designer drugs, ethanol and/or cocaine is shown to be more likely to produce toxic symptoms requiring clinical attendance in a hospital emergency room. These findings along with the consumption history, the concentrations of drugs and metabolites in urine and serum and the toxicological significance for the interpretation of some MDMA metabolites such as 4-hydroxy-3-methoxymethamphetamine (HMMA) are discussed in this study. 相似文献