全文获取类型
| 收费全文 | 23065篇 |
| 免费 | 258篇 |
专业分类
| 各国政治 | 717篇 |
| 工人农民 | 861篇 |
| 世界政治 | 1501篇 |
| 外交国际关系 | 792篇 |
| 法律 | 14986篇 |
| 中国共产党 | 35篇 |
| 中国政治 | 210篇 |
| 政治理论 | 4006篇 |
| 综合类 | 215篇 |
出版年
| 2023年 | 108篇 |
| 2021年 | 129篇 |
| 2020年 | 491篇 |
| 2019年 | 485篇 |
| 2018年 | 594篇 |
| 2017年 | 684篇 |
| 2016年 | 738篇 |
| 2015年 | 640篇 |
| 2014年 | 635篇 |
| 2013年 | 2064篇 |
| 2012年 | 514篇 |
| 2011年 | 637篇 |
| 2010年 | 737篇 |
| 2009年 | 752篇 |
| 2008年 | 602篇 |
| 2007年 | 605篇 |
| 2006年 | 684篇 |
| 2005年 | 563篇 |
| 2004年 | 525篇 |
| 2003年 | 476篇 |
| 2002年 | 447篇 |
| 2001年 | 749篇 |
| 2000年 | 663篇 |
| 1999年 | 531篇 |
| 1998年 | 312篇 |
| 1997年 | 250篇 |
| 1996年 | 256篇 |
| 1995年 | 248篇 |
| 1994年 | 270篇 |
| 1993年 | 244篇 |
| 1992年 | 393篇 |
| 1991年 | 449篇 |
| 1990年 | 405篇 |
| 1989年 | 412篇 |
| 1988年 | 417篇 |
| 1987年 | 372篇 |
| 1986年 | 403篇 |
| 1985年 | 404篇 |
| 1984年 | 374篇 |
| 1983年 | 326篇 |
| 1982年 | 248篇 |
| 1981年 | 244篇 |
| 1980年 | 219篇 |
| 1979年 | 241篇 |
| 1978年 | 181篇 |
| 1977年 | 151篇 |
| 1976年 | 132篇 |
| 1975年 | 141篇 |
| 1974年 | 143篇 |
| 1973年 | 143篇 |
排序方式： 共有10000条查询结果，搜索用时 15 毫秒
961.
Methoxetamine (MXE) is a new synthetic drug of abuse structurally related to ketamine and phencyclidine. A case of a 29-year-old male with acute toxicity related to the analytically confirmed use of MXE is reported. The man was found dead at his residence. Biological material was analyzed using liquid chromatography–tandem mass spectrometry. The concentration of MXE in urine of the deceased was 85 μg/mL. Despite the vial containing the blood sample being destroyed during transportation and the blood leaking out into the cardboard packaging, the blood level of MXE was estimated. After determination of the cardboard grammage (approx. 400 g/m3) and the mean mass of the blood obtained after drying (0.1785 ± 0.0173 g per 1 mL), the estimated blood concentration of MXE was found to be 5.8 μg/mL. The high concentration of MXE in blood and urine and the circumstances of the case indicate an unintentional, fatal intoxication with this substance. 相似文献
962.
Huipin Wang M.D. Yan Liu M.D. Jian Zhao B.D. Sunlin Hu Ph.D. Yuzhong Wang M.D. Chao Liu Ph.D. Yanji Zhang B.D. 《Journal of forensic sciences》2015,60(Z1):S227-S230
Presence of diatoms in tissues has been considered as a significant sign of drowning. However, there are limitations in the present extraction methods. We developed a new digestion method using the Lefort aqua regia solution (3:1 nitric acid to hydrochloric acid) for diatom extraction and evaluated the digestive capability, diatom destruction, and diatoms' recovery of this new method. The kidney tissues from rabbit mixed with water rich in diatoms were treated by the Lefort aqua regia digestion method (n = 10) and the conventional acid digestion method (n = 10). The results showed that the digestive capability of Lefort aqua regia digestion method was superior to conventional acid digestion method (p < 0.01); the structure of diatom remained almost intact; and the recovery of diatom was comparable to the conventional acid digestion method (p > 0.05). The Lefort aqua regia reagent is an improvement over the conventional acid digestion for recovery of diatoms from tissue samples. 相似文献
963.
Latent fingerprint deposits on thermal paper sourced from the U.S., China, the U.K., and Australia have been visualized by heating. U.S. and Chinese sourced paper produced two distinct types of fingerprint development. In one type (type 1), the paper dye colors where the deposit is present (as previously reported) and in the other type (type 2) the ‘inverse’ of this gives paper coloring only in areas not coincident with the deposit. Both development types gave identifiable fingerprints, the majority fading within 24 h of heating. Fingerprint development from U.K. and Australian sourced paper was exclusively type 1 and resistant to fading. Temperatures for fingerprint visualization were higher for U.S. paper (64–71°C) and Chinese paper (75–95°C) than for U.K. and Australian sourced paper (43–50°C). Particularly for Chinese sourced paper, these temperatures were within a few degrees of the normal paper color temperature. A mechanism for type 2 fingerprint development is proposed. 相似文献
964.
Homicide–suicide represents a single episode of violence which may decimate an entire family. This study aimed to further describe motives and context of these tragedies. Psychological autopsies were completed for 18 homicide–suicide cases in Dallas, Texas. This included postevent interviews with surviving family members and review of police and coroner records. Two‐thirds of perpetrators had made either verbal or written threats prior to the homicide–suicide. A simplified typology describing victim–perpetrator relationship and motive type is suggested for future studies and clinical ease. Two‐thirds of perpetrators fell into the category of Intimate‐Possessive, most of whom were depressed men who were abusing substances and undergoing separation. Additional categories included Intimate‐Ailing, Filial‐Revenge, Familial‐Psychotic, and Friend‐Psychotic. Further, implications from this psychological autopsy study regarding risk assessment include use of collateral interviews regarding threats and past violence. 相似文献
965.
Geroncio C. Fajardo M.D. M.B.A. M.S. M.S. Joseph Posid M.P.H. Stephen Papagiotas M.P.H. Luis Lowe M.S. M.P.H. 《Journal of forensic sciences》2015,60(Z1):S76-S82
There have been periodic electronic news media reports of potential bioterrorism-related incidents involving unknown substances (often referred to as “white powder”) since the 2001 intentional dissemination of Bacillus anthracis through the U.S. Postal System. This study reviewed the number of unknown “white powder” incidents reported online by the electronic news media and compared them with unknown “white powder” incidents reported to the U.S. Centers for Disease Control and Prevention (CDC) and the U.S. Federal Bureau of Investigation (FBI) during a 2-year period from June 1, 2009 and May 31, 2011. Results identified 297 electronic news media reports, 538 CDC reports, and 384 FBI reports of unknown “white powder.” This study showed different unknown “white powder” incidents captured by each of the three sources. However, the authors could not determine the public health implications of this discordance. 相似文献
966.
Kristen Leigh Boyd B.S. Chiara Villa M.Sc. Niels Lynnerup M.D. Ph.D. 《Journal of forensic sciences》2015,60(2):363-369
We examined the utility of CT scans in the evaluation of degree of ectocranial suture closure. Five cranial points (left and right midcoronal positions, left and right midlambdoidal positions, and the lambda) were evaluated in 231 CT scans using a three‐point scoring system (open, partial closed, and closed). The slice increment and thickness varied between three groups of the scans. The results showed a good correlation between degree of suture closure and increasing age in each group. Young individuals (<40 years) and old individuals (>60 years) could be clearly distinguished from the middle‐aged individuals. ANOVA test revealed no difference between two groups of scans and between left and right sides (p > 0.05). Interobserver agreement was good, especially considering the score by sides. The results of this study create the base for developing a robust and simple method to estimate the age at death using CT scans. 相似文献
967.
Jess Beck M.A. Ian Ostericher M.A. Gregory Sollish B.A. Jason De León Ph.D. 《Journal of forensic sciences》2015,60(Z1):S11-S20
Since 1998, over 5500 people have died while attempting to cross the U.S.–Mexico border without authorization. These deaths have primarily occured in the Arizona desert. Despite the high volume of deaths, little experimental work has been conducted on Sonoran Desert taphonomy. In this study, pig carcasses were used as proxies for human remains and placed in different depositional contexts (i.e., direct sunlight and shade) that replicate typical sites of migrant death. Decomposition was documented through daily site visits, motion-sensitive cameras and GIS mapping, while skeletal preservation was investigated through the collection of the remains and subsequent faunal analysis. Our results suggest that vultures and domestic dogs are underappreciated members of the Sonoran scavenging guild and may disperse skeletal remains and migrant possessions over 25 m from the site of death. The impact of scavengers and the desert environment on the decomposition process has significant implications for estimating death rates and identifying human remains along the Arizona/Mexico border. 相似文献
968.
Patricia E. J. Wiltshire D.Sc. David L. Hawksworth D.Sc. Kevin J. Edwards D.Sc. 《Journal of forensic sciences》2015,60(6):1441-1450
A rapid method for evaluating suspect testimony is valuable at any stage in an inquiry and can result in a change of direction in an investigation. Rape cases, in particular, can present problems where a defendant renders DNA analysis redundant by claiming that the claimant consented to have sexual relations. Forensic palynology is valuable in confirming or eliminating locations as being crime scenes, thus checking the testimony of both parties. In contrast to some forensic disciplines, forensic palynology can provide critical information without time-consuming full analysis. Two cases are described where the palynological assemblages from comparator samples of pertinent places were compared with those obtained from clothing of claimants and defendants. The results of rapid microscopical scanning of relevant preparations led to early confessions, thus obviating the need for costly analyses and protracted court proceedings. A third case demonstrates the unbiased nature of this technique where a man, although innocent of any offense, lied about having visited the crime scene for fear of prosecution. This highlights the need for sensitive policing in claims of rape. 相似文献
969.
Björn Bäckström M.D. Bengt Johansson M.D. Ph.D. Anders Eriksson M.D. Ph.D. 《Journal of forensic sciences》2015,60(6):1662-1665
Nitrous oxide is an inflammable gas that gives no smell or taste. It has a history of abuse as long as its clinical use, and deaths, although rare, have been reported. We describe two cases of accidental deaths related to voluntary inhalation of nitrous oxide, both found dead with a gas mask covering the face. In an attempt to find an explanation to why the victims did not react properly to oncoming hypoxia, we performed experiments where a test person was allowed to breath in a closed system, with or without nitrous oxide added. Vital signs and gas concentrations as well as subjective symptoms were recorded. The experiments indicated that the explanation to the fact that neither of the descendents had reacted to oncoming hypoxia and hypercapnia was due to the inhalation of nitrous oxide. This study raises the question whether nitrous oxide really should be easily, commercially available. 相似文献
970.
Lisa B. E. Shields M.D. Cristin M. Rolf M.D. John C. Hunsaker III M.D. J.D. 《Journal of forensic sciences》2015,60(6):1647-1651
Excited delirium denotes a life-threatening medical condition characterized by the acute onset of agitated and violent behavior that often results in a sudden and unexplained death. Cocaine-induced excited delirium refers to fatal cocaine intoxication with the following symptoms occurring sequentially: hyperthermia, delirium with agitation, respiratory arrest, and death. We present a case of cocaine-induced excited delirium in a cocaine “body packer” or a “mule”, specifically an individual who attempts to smuggle cocaine within the body. Investigators at the scene initially suspected homicide due to the victim's sharp and blunt force injuries. Three rubber packets containing cocaine were removed from the victim's rectum. Blood toxicological analysis revealed an alcohol concentration of 0.016 g/100 and cocaine >1 mg/L. The forensic pathologist should consider cocaine-induced excited delirium when an individual exhibits aggressive behavior, unexpected strength, and resistance to pain who dies suddenly. Further analysis should be performed during the scene investigation and autopsy for evidence of body packing. 相似文献