首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   10003篇
  免费   529篇
各国政治   640篇
工人农民   278篇
世界政治   601篇
外交国际关系   393篇
法律   6465篇
中国共产党   39篇
中国政治   305篇
政治理论   1645篇
综合类   166篇
  2021年   60篇
  2020年   201篇
  2019年   226篇
  2018年   297篇
  2017年   308篇
  2016年   331篇
  2015年   295篇
  2014年   242篇
  2013年   999篇
  2012年   302篇
  2011年   386篇
  2010年   369篇
  2009年   394篇
  2008年   336篇
  2007年   332篇
  2006年   372篇
  2005年   264篇
  2004年   272篇
  2003年   252篇
  2002年   241篇
  2001年   375篇
  2000年   320篇
  1999年   258篇
  1998年   116篇
  1997年   79篇
  1996年   83篇
  1995年   89篇
  1994年   98篇
  1993年   90篇
  1992年   159篇
  1991年   172篇
  1990年   151篇
  1989年   163篇
  1988年   134篇
  1987年   150篇
  1986年   135篇
  1985年   144篇
  1984年   105篇
  1983年   126篇
  1982年   88篇
  1981年   88篇
  1980年   57篇
  1979年   114篇
  1978年   74篇
  1977年   60篇
  1976年   51篇
  1975年   48篇
  1974年   56篇
  1973年   57篇
  1972年   44篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Semaan et al. (J Forensic Res, 2020, 11, 453) discuss a mock case “where eight different individuals [P1 through P8] could not be excluded in a mixed DNA analysis. Even though … expert DNA mixture analysis software was used.” Two of these are the true donors. The LRs reported are incorrect due to the incorrect entry of propositions into LRmix Studio. This forced the software to account for most of the alleles as drop-in, resulting in LRs 60–70 orders of magnitude larger than expected. P1, P2, P4, P5, and P8 can be manually excluded using peak heights. This has relevance when using LRmix which does not use peak heights. We extend the work using the same two reference genotypes who were the true contributors as Semaan et al. (J Forensic Res, 2020, 11, 453). We simulate three two-donor mixtures with peak heights using these two genotypes and analyze using STRmix?. For the simulated 1:1 mixture, one of the non-donors’ LRs supported him being a contributor when no conditioning was used. When considered in combination with any other potential donors (i.e., with conditioning), this non-donor was correctly eliminated. For the 3:1 mixture, all results correctly supported that the non-donors were not contributors. The low-template 4:1 mixture LRs with no conditioning showed support for all eight profiles as donors. However, the results from pair-wise conditioning showed that only the two ground truth donors had LRs supporting that they were contributors to the mixture. We recommend the use of peak heights and conditioning profiles, as this allows better sensitivity and specificity even when the persons share many alleles.  相似文献   
2.
Tim Spier 《German politics》2019,28(2):282-303
While political parties in Germany have been steadily losing members for more than two decades, there has been no sign of a breakdown in their day-to-day grass-roots activities. Despite many prophecies of doom, the ‘party on the ground’ does not seem to be dead yet. There is some evidence that the declining number of party members is compensated for by an increasing share of party activists. The question is how the erosion of the political parties’ member-ship base affects their levels and types of activity. This paper aims to describe and explain these two dimensions of activity in German political parties, using data from German party membership studies from 1998 and 2009. The analyses show that parties are partly able to compensate for membership losses via an increased activity of the remaining members, but at the same time, it is possible that changes in the social profile and motivations of the most active group of members may lead to future difficulties in coping with party work and canvassing new members.  相似文献   
3.
This study describes the performance of handheld Raman devices for determining whether suspect pharmaceutical tablets declared to contain controlled substances were consistent with authentic (CWA) or not consistent with authentic (NCWA) tablets using a simple, rapid, field-friendly method capable of being used by nonexperts. Twenty-five authentic products and 84 known NCWA tablets were examined using three “parent” devices for a total of 327 analyses. On average, the parent devices yielded a true pass rate of 100%, a true fail rate of 98.4%, a false pass rate of 1.6%, and a false fail rate of 0%. The methods/libraries were then transferred to 13 identical “daughter” devices, which were used to examine 10 suspect finished dosage forms in duplicate (six known NCWA tablets and four authentic tablets) for a total of 260 measurements. On average, the daughter devices had a true pass rate of 100%, a true fail rate of 95.5%, a false pass rate of 4.5%, and a false fail rate of 0.0%. These data demonstrate that the parent–daughter electronic transfer method was successful, which permits the ability to develop methods in the laboratory that can be seamlessly pushed out to field devices. The methods can then be used to (i) prioritize samples for additional testing using other more time-consuming laboratory-based techniques needed to detect and quantify active ingredients and (ii) help support the interdiction of dangerous tablets at ports of entry, thereby preventing them from reaching the supply chain.  相似文献   
4.
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   
5.
Fatal fall from a height initiated with a swinging motion on the sagittal plane of the victim's body is examined. Method of analytical mechanics is adopted to establish the functional relations between the swinging angle of the body and the force needed to sustain the body until release, and the amount of the horizontal displacement that would occur after release. The analysis is applied to support an expert opinion presented in a criminal court in which two accused were convicted of murder for dropping a female victim from a bridge. The results indicate that it is unlikely for the body to locate as recorded by the police investigation report in the case. This study demonstrates that a straightforward mechanical analysis can be utilized to examine uncommon falling scenarios.  相似文献   
6.
The literature on child sexual abuse (CSA) perpetrated by female sexual offenders (FSOs) is exiguous, and many studies have focused on judicial databases. The present retrospective study, instead, analyzed clinical and judicial data of a group of both victims and alleged FSOs, to additionally include women who have not been convicted by the criminal justice system, but who hold strong clinical suspicions of being perpetrators of CSA. The medical records and the Court files of 11 children and their eight suspected FSOs have been collected and critically reviewed in light of the literature to date. This approach allowed for a deeper understanding of the relationship between child and FSO. The authors hypothesize that the victims’ severe psychopathological outcomes were a result of a failure to develop appropriate attachments with their prospective caregivers, which could have been damaged by the pathological relationship with FSOs, who were the victims’ caregivers.  相似文献   
7.
The problem‐solving capacity and problem‐generating potential of multilevel systems entail the need for the delegation of authority. When the problem concerned is about how to put an abstract policy concept into a practicable policy tool, the choice of the respective delegation trajectory depends on the policy models or the policy‐relevant knowledge that the respective political levels can supply. When regarding the European Union (EU) level as the starting point of knowledge creation and delegation trajectories, and concentrating on transaction costs, policy knowledge and models generated at the international level provide the most cost‐effective solution. Only when the international level is not able to provide further policy knowledge and innovation does the EU delegate its definitional authority, first downward to the member states and then sideways to EU agencies. We illustrate the plausibility of our dynamic understanding of multilevel governance by using Environmental Policy Integration as an example.  相似文献   
8.
The Journal of Technology Transfer - Despite the growing interest in understanding innovative activities, an important limitation of the current literature on innovation—both public and...  相似文献   
9.
An important component of crime scene reconstruction is bloodstain pattern analysis (BPA). Where BPA concerns impact patterns, estimating the area of origin is critical information for scene reconstruction. Traditionally, this is achieved by measuring individual bloodstains and performing trigonometric calculations; however, 3D scanning has been proposed as a viable alternative for overcoming logistical and practical concerns with the manual method. Therefore, this project aimed to establish whether the FARO Focus 3D scanner and FARO Zone 3D software can improve the accuracy of area of origin estimates relative to the manual method. We created a series of eight bloodstain impact patterns and performed paired analysis using the two methods to estimate areas of origin for each pattern. Our data suggested that FARO-derived estimates were generally more accurate than using the manual method. FARO-estimated heights of origin areas were generally closer to the true distance. Both methods underestimated the distance from the wall for most patterns originating 150mm or greater from the wall, but overestimated distances for patterns originating closer to the wall. The degree to which distances were underestimated increased significantly the further the blood source was from the wall and was greater for FARO-derived estimates. The results of this research contribute to the validation of these instruments for operational implementation for BPA and should be considered alongside the practical benefits of 3D scanning relative to manual methods. Further, 3D scanning can provide reliable BPA reconstruction documentation for technical review and court presentation.  相似文献   
10.
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   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号