全文获取类型
收费全文 | 8133篇 |
免费 | 489篇 |
专业分类
各国政治 | 394篇 |
工人农民 | 380篇 |
世界政治 | 534篇 |
外交国际关系 | 271篇 |
法律 | 5523篇 |
中国政治 | 50篇 |
政治理论 | 1432篇 |
综合类 | 38篇 |
出版年
2023年 | 43篇 |
2020年 | 183篇 |
2019年 | 194篇 |
2018年 | 230篇 |
2017年 | 249篇 |
2016年 | 248篇 |
2015年 | 229篇 |
2014年 | 209篇 |
2013年 | 863篇 |
2012年 | 184篇 |
2011年 | 203篇 |
2010年 | 229篇 |
2009年 | 263篇 |
2008年 | 196篇 |
2007年 | 202篇 |
2006年 | 199篇 |
2005年 | 198篇 |
2004年 | 217篇 |
2003年 | 184篇 |
2002年 | 169篇 |
2001年 | 322篇 |
2000年 | 272篇 |
1999年 | 237篇 |
1998年 | 108篇 |
1997年 | 76篇 |
1996年 | 85篇 |
1995年 | 87篇 |
1994年 | 100篇 |
1993年 | 93篇 |
1992年 | 162篇 |
1991年 | 172篇 |
1990年 | 157篇 |
1989年 | 165篇 |
1988年 | 127篇 |
1987年 | 142篇 |
1986年 | 140篇 |
1985年 | 144篇 |
1984年 | 109篇 |
1983年 | 127篇 |
1982年 | 93篇 |
1981年 | 84篇 |
1980年 | 62篇 |
1979年 | 112篇 |
1978年 | 74篇 |
1977年 | 64篇 |
1976年 | 51篇 |
1975年 | 50篇 |
1974年 | 58篇 |
1973年 | 55篇 |
1972年 | 45篇 |
排序方式: 共有8622条查询结果,搜索用时 15 毫秒
181.
Marloes E. M. Vester M.D. Ph.D. Kurt B. Nolte M.D. Ph.D. Gary M. Hatch M.D. Chandra Y. Gerrard M.P.H. B.S. Reinoud D. Stoel Ph.D. Rick R. van Rijn M.D. Ph.D. 《Journal of forensic sciences》2020,65(5):1568-1573
Postmortem computed tomography (PMCT) is integrated into the evaluation of decedents in several American medical examiner offices and medicolegal death investigative centers in many other countries. We retrospectively investigated the value of PMCT in a series of firearm homicide cases from a statewide centralized medical examiner’s office that occurred during 2016. Autopsies were performed or supervised by board-certified forensic pathologists who reviewed the PMCT scans prior to autopsy. PMCT scans were re-evaluated by a forensic radiologist blinded to the autopsy findings and scored by body region (head–neck, thoracoabdominal, and extremities). Injury discrepancies were scored using a modified Goldman classification and analyzed with McNemar’s test. We included 60 males and 20 females (median age 31 years, range 3–73). Based on PMCT, 56 (79.1%) cases had injuries relevant to the cause of death in a single body region (24 head–neck region, 32 thoracoabdominal region). Out of these 56 cases, 9 had a missed major diagnosis by PMCT outside that region, including 6 extremity injuries visible during standard external examination. Yet all had evident lethal firearm injury. We showed that PMCT identifies major firearm injuries in homicide victims and excludes injuries related to the cause of death in other regions when a single body region is injured. Although PMCT has a known limited sensitivity for soft tissue and vascular pathology, it can be combined with external examination to potentially reduce or focus dissections in some of these cases depending on the circumstances and medicolegal needs. 相似文献
182.
Adam Lanzarotta Ph.D. Michael D. Thatcher B.S. Lisa M. Lorenz B.S. JaCinta S. Batson M.S. 《Journal of forensic sciences》2020,65(5):1443-1449
A simple, quick, selective, sensitive, and effective field-friendly method capable of being used by nonexperts has been developed for detecting mitragynine in Mitragyna speciosa (kratom) using surface-enhanced Raman spectroscopy (SERS). Over 100 samples and blanks (known to be either positive or negative for the presence of mitragynine) were examined in duplicate using five identical handheld Raman spectrometers, which provided a data set of over 1,000 examinations. Based on the results of these analyses, the method yielded a true-positive rate of 99.3%, a true-negative rate of 97.9%, a false-positive rate of 2.1%, and a false-negative rate of 0.7%. The average minimum detectable concentration (Cm) of mitragynine that reproducibly yielded a match for one of the library spectra on all five instruments was determined to be 342 ng/mL (ppb). This Cm value is a conservative estimate considering that the extraction process was not fully optimized by this study, which was not necessary since the Cm value achieved was well below typical mitragynine concentrations in kratom (1.3–2.3%). The method is ideal (i) for prioritizing samples for additional testing using other more time-consuming laboratory-based techniques needed to detect and quantify mitragynine and (ii) for field use at international mail facility (IMF) satellite laboratories to help interdict kratom and prevent this dangerous product from reaching the U.S. supply chain. 相似文献
183.
Dalia M. Al-Saif M.B.B.S. S.B.F.L.M. Maram A. Al-Farayedhi M.B.B.S. S.B.F.L.M Ghadah A. Al-Shamsi M.B.B.S. S.B.F.L.M. Marwah I. Al-Bayat M.B.B.S. S.B.F.L.M. Osama M. Almadani M.D. Ph.D. F.F.F.L.M. Magdy A. Kharoshah M.B.Bch. M.Sc. M.D F.F.F.L.M. 《Journal of forensic sciences》2020,65(5):1574-1578
Examination of the female external genitalia to assess for sexual abuse is performed in living individuals, and the interpretation of the findings is based on evidence-based studies. However, in the deceased, no such studies are available, and postmortem changes could present as suspicious findings that can be mistaken for trauma. Patches of discoloration in the hymen were reported previously in one case as hypostasis (i.e., livor and lividity), and based on this finding, it was listed as a finding that is not associated with trauma. This was a retrospective study that was conducted in the Center of Forensic and Legal Medicine in Dammam, Saudi Arabia over a 4-year period. The study included 30 deceased women in whom photographic documentation of their external genitalia was assessed for postmortem changes. The postmortem interval ranged from less than 24 h to more than 100 days, and the ages of these deceased women were in the 20–40 year-old age group. In cases where the hymen, vagina, and/or fossa navicularis were clearly visible, none of these areas showed any hypostatic discoloration. A comparison between antemortem and postmortem appearance of the hymen in one case clearly showed the absence of hypostatic changes in the hymen. In conclusion, any discoloration of the external genitalia that is detected in a female decedent requires serious consideration. 相似文献
184.
When a bullet punctures a surface, it leaves behind a bullet impact, which can be analyzed in order to determine the origin and trajectory path from which a bullet was discharged using many different scientific methods to reconstruct a shooting scene. The purpose of the research was to test the accuracy and repeatability of reconstructing the impact angle of single bullet impacts using the ellipse method. The research was conducted by firing various calibers of ammunition into drywall panels positioned at varying angles of incidence from 88° until ricochet occurred. This was done in order to determine which caliber type and angle of incidence are most accurate and precise for reconstructing a shooting scene. The study examined four caliber types fired into drywall panels, with 5 repeated shots for each of the 11 angles of incidence (n = 220). Furthermore, 31 participants partook in the study to estimate a bullet impact angle of incidence utilizing the ellipse method. The results show that the best performance (accuracy and repeatability) is seen with the measurements of the 0.45 caliber ammunition. When angle of incidences is low (<64°), the performance (accuracy and repeatability) was seen to be better in all caliber ammunitions. Overall, the data provided for single bullet impacts deposited in drywall show that the ellipse method is useful in providing measurements for most crime scene reconstruction purposes and has also demonstrated that results vary depending on the type of ammunition, firearm, and angle of incidence being examined. 相似文献
185.
186.
Jessica E. Sanger Ciarleglio M.A. Kristen M. Perez M.S. Haley L. Motola M.S. Elizabeth A. DiGangi Ph.D. 《Journal of forensic sciences》2020,65(5):1698-1703
Dermestid beetles (Dermestes maculatus De Geer 1774) are small carrion insects characterized by a rounded or oval-shaped body and white abdomen with black markings. Given their natural propensity to consume soft tissue throughout various stages of decomposition, biological anthropologists have sought to use dermestids as a forensic processing method in addition to traditional chemical tissue removal techniques. Although useful, most of the existing academic literature regarding the upkeep of dermestid colonies for skeletal remains processing either lack specificity or are outdated. Additionally, nonacademic sources that contain information regarding dermestid maintenance are often disjointed, resulting in a difficulty to replicate habitat construction and ideal environmental conditions. Therefore, this technical note presents recommendations for anthropologists interested in establishing and maintaining a D. maculatus population. These recommendations are based on our experiences using several dermestid colonies to process five unembalmed human heads, procured from an anatomical gift company for a larger study on gunshot trauma. Aspects of the dermestids’ environment that are crucial for the management of a healthy colony include the type of bedding, food, water, and containment method used, in addition to maintaining appropriate temperature ranges (24–27°C) and humidity levels (35–73%). Although habitat construction and dermestid maintenance involve materials that are relatively inexpensive and readily available, setting up and maintaining a D. maculatus colony can be laborious and time consuming and should only be undertaken when the volume of casework is such that this investment would be offset. 相似文献
187.
Sophia K. Chiu M.D. M.P.H. Jessica F. Li M.S.P.H. Kurt B. Nolte M.D. 《Journal of forensic sciences》2020,65(4):1324-1327
Recent increases in deaths in the United States from synthetic opioids such as fentanyl and fentanyl analogues (fentanyls) have raised concerns about possible occupational exposures to these potent agents. Medicolegal death investigators and autopsy suite staff might perform job tasks involving exposure to fentanyls. The potential for exposure to fentanyls among medicolegal death investigators and autopsy technicians at a state medical examiner's office was evaluated through review of caseload characteristics, injury and illness logs, and procedures and policies and discussions with management and employee representatives. The evaluation showed that this medical examiner's office had low potential for work-related exposure to fentanyls; its standard operating procedures and personal protective equipment requirements should reduce the potential for occupational exposure. Medicolegal death investigation agencies can develop and implement guidance to control exposures and provide workforce education and training to reduce the potential for work-related exposure to fentanyls. 相似文献
188.
The present study provides a comparative analysis of sexual-minority and heterosexual emerging adult women’s experiences seeking support for sexual issues from parents and friends. Participants included 229 college women (88 sexual-minority women; 141 heterosexual women), ranging from 18 to 25 years of age, who provided written responses to an inquiry about a time they went to friends and parents for support for a issue related to their sexuality. Responses indicated that the majority of participants had sought support from either a parent or a friend and that mothers and female friends were more likely involved than fathers or male friends, respectively. Sexual issues that participants reported discussing with parents and friends were inductively grouped into five categories: dating and romantic relationships, sexual behavior, sexual health, identity negotiation, and discrimination and violence. Issues that were discussed differed based on sexual orientation identity and the source of support (parent or friend); they did not differ by age. Participants generally perceived parents and friends’ responses as helpful, though sexual-minority participants perceived both parents and friends’ responses as less helpful than did heterosexual participants. Overall, results suggest both similarities and differences between sexual-minority and heterosexual young women’s experiences seeking support for sexual issues from parents and friends. 相似文献
189.
190.
Raymond B. Firehock John A. Gentry Julia W. Rogers James M. Simon Jr 《Intelligence & National Security》2018,33(5):774-783
The literature on intelligence analysis contains many references to the ‘review process’, the mechanism by which analysts’ drafts are converted into corporate products. Analysts whose drafts consistently navigate the process quickly and smoothly are regarded as star performers. Divining the practical meaning of organizational definitions of ‘good’ analysis and the personal preferences of specific senior reviewers is not easy, however. Analysts occasionally commit their understanding of reviewers’ stylistic preferences to paper, effectively providing style guides to help others. This essay presents and explains the development and implications of one such guide, which was designed to help analysts in CIA’s Office of Strategic Research in the early 1970s. 相似文献