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   2690篇
  免费   166篇
各国政治   254篇
工人农民   159篇
世界政治   324篇
外交国际关系   189篇
法律   1404篇
中国政治   10篇
政治理论   497篇
综合类   19篇
  2024年   4篇
  2023年   41篇
  2022年   21篇
  2021年   43篇
  2020年   94篇
  2019年   112篇
  2018年   138篇
  2017年   178篇
  2016年   177篇
  2015年   117篇
  2014年   157篇
  2013年   505篇
  2012年   142篇
  2011年   108篇
  2010年   72篇
  2009年   63篇
  2008年   97篇
  2007年   110篇
  2006年   75篇
  2005年   70篇
  2004年   83篇
  2003年   56篇
  2002年   43篇
  2001年   46篇
  2000年   51篇
  1999年   28篇
  1998年   26篇
  1997年   16篇
  1996年   14篇
  1995年   19篇
  1994年   11篇
  1993年   13篇
  1992年   12篇
  1991年   11篇
  1990年   8篇
  1989年   9篇
  1988年   7篇
  1987年   8篇
  1986年   4篇
  1985年   4篇
  1984年   6篇
  1983年   8篇
  1982年   3篇
  1979年   3篇
  1975年   4篇
  1974年   4篇
  1973年   4篇
  1972年   5篇
  1967年   6篇
  1965年   4篇
排序方式: 共有2856条查询结果,搜索用时 15 毫秒
71.
Ammonium nitrate fuel oil is an explosive mixture found in most antipersonnel landmines (APL) buried throughout the Colombian territory. During more than 50 years of internal conflict, the Colombian government has found that trained dogs are the most effective method to detect APL. However, the olfactive signature in ANFO is unknown and also if there are differences in detection related to the explosive manufacturing origin. Therefore, this work begins with the analytical validation of the method used to determine ammonia, in its derivatized form as carbamate, released by home-made ANFO using HS-SPME-GC-FID. Once validated, the method was used to identify ammonia and other organic volatile compounds present in ANFO, under laboratory and simulated field conditions. The validation process includes the evaluation of the optimum conditions for the derivation and extraction of butylcarbamate, the determination of the working ranges with linear response in FID, the limits of detection and quantification, the sensitivity, and the precision. The results of the validation established linearity and sensitivity in a concentration between 20 and 120 mg/L, as well as low limits of detection and quantification of 6.4 and 21.4 mg/L, respectively. Also, an intermediate precision of 11% for butylcarbamate with a repeatability of 8%. The validated method showed in real samples of home-made ANFO besides ammonia, the presence of low molecular methylamines, and also exhibited differences in volatile compositions according to the origin. The objective of this work is to offer a reliable analytical methodology for the extraction and analysis of volatile compounds from ANFO.  相似文献   
72.
Gunshot residue (GSR) analysis and their interpretation provide crucial information on a criminal investigation involving the use of firearms. To date, several approaches have been proposed for the implementation of a combined sampling and analysis of inorganic (IGSR) and organic GSR (OGSR). However, it is not clear at this stage if concurrent analyses of both types of residue might be detrimental to the analysis of IGSR currently applied in forensic laboratories. Thus, this work aims to compare and evaluate three different protocols for the combined collection and analysis of IGSR and OGSR. These methods, respectively, involve the use of a modified stub (with two halves, one for the detection of IGSR and the other for the analysis of OGSR); the sequential recovery of GSR with two stubs mounted with different adhesives (double-sided carbon tape and Tesa® TACK) and the sequential analysis of IGSR and OGSR from a single carbon stub following carbon deposition. The detection of IGSR was carried out using SEM-EDX, while OGSR analysis was performed using ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS). Obtained results for experiments performed using Geco Sinoxid® ammunition indicated that sequential analysis was the most suitable protocol for the combined collection and analysis of both IGSR and OGSR. A higher number of inorganic (characteristic and consistent) particles and higher concentrations of ethylcentralite, N-nitrosodiphenylamine, diphenylamine, and nitroglycerin were recovered with this method.  相似文献   
73.
ABSTRACT

Studies have demonstrated the efficacy of the Scharff technique for gathering human intelligence, but little is known about how this efficacy might vary among different samples of practitioners. In this training study we examined a sample of military officers (n?=?37). Half was trained in the Scharff technique and compared against officers receiving no Scharff training. All officers received the same case file describing two sources holding information about a terrorist attack. University students (n?=?74) took the role of the semi-cooperative sources. Scharff-trained officers adhered to the training as they (1) aimed to establish the ‘knowing-it-all’ illusion, (2) posed claims as a means of eliciting information, and (3) asked fewer explicit questions. The ‘untrained’ officers asked many explicit questions, questioned the reliability of the provided information, pressured the source, and displayed disappointment with the source's contribution. Scharff-trained officers were perceived as less eager to gather information and left their sources with the impression of having provided comparatively less new information, but collected a similar amount of new information as their untrained colleagues. The present paper both replicates and advances previous work in the field, and marks the Scharff technique as a promising technique for gathering human intelligence.  相似文献   
74.

The aim of this paper is to examine the influence of the right to information laws on sustainability transparency in European local governments. This goal is novel, in that previous studies have examined the effects of various factors on the dissemination of government information (demographic, socioeconomic, political and financial) but not the contribution of legal factors to online transparency on environmental, social and economic sustainability. Our research question is this: Do information laws contribute to transparency on sustainability? Using the Global Reporting Initiative guidelines and a statistical regression analysis, we studied the websites of 106 local governments in ten European countries. The results obtained show that when transparency laws clearly stipulate the rules applicable and the procedures established for appeals, exceptions, refusals and requests, this can favour transparency on environmental, social and economic sustainability. Our findings advance understanding of this field and reinforce the basis for legal reforms to enhance sustainability transparency.

  相似文献   
75.
76.
Postmortem stability of DNA   总被引:11,自引:0,他引:11  
High-molecular-weight DNA was recovered postmortem in sufficient quantities from various human organ tissues as well as from blood, although not all organs were equally well suitable. Good DNA stability was found in brain cortex, lymph nodes and psoas muscle over a period of three weeks postmortem. Spleen and kidney showed good DNA stability up to five days postmortem but after longer periods, rapid degradation was observed. Yields of DNA from blood were not consistent because of the non homogeneity of samples. Blood clots were rich with DNA. Generally, the amount of degraded DNA correlated directly with the duration of the postmortem period. However in some cases, DNA degradation was already prominent after a short period. However in some cases, DNA degradation was already prominent after a short period. Case histories showed that high environmental temperature at the site of death and/or infectious diseases prior to death were the main factors for rapid autolysis. Gradual disappearance to complete loss of the long fragments (15-23 kb) was observed in DNA fingerprinting using the minisatellite probe 33.15. No extra-bands were noted, thus excluding erroneous conclusions. However, evidentiary value of older samples was lower.  相似文献   
77.
Although the Great Depression has been the subject of much research, focus normally centers on the impact instead of the tactics developed by working-class organizations to tackle the problems it caused, specifically unemployment. Recent research has sought to fill this gap, but numerous areas remain uncovered. This paper covers two of these: the situation in Spain and the reaction of anarcho-syndicalist union – the Confederación Nacional de Trabajo. Spain presents an anomalous case; a country that saw the replacement of a semi-fascist dictatorship by a democracy in the 1930s. Furthermore, the fact that the initial government of the Spanish Second Republic included the Socialists provides an opportunity of comparing and contrasting the positions and policies of reformist and revolutionary workers’ organizations. The study is based on predominantly on articles appearing in the CNT newspaper Solidaridad Obrera. The conclusion reached is that for the CNT rising unemployment was a symptom of an irreversible trend in a failing capitalist system, which could only be solved by the revolutionary overthrow of that system. Nonetheless, the union had to present plausible solutions to ameliorate the conditions of the workers to attract the unemployed and thus, create a force strong enough to lead that revolutionary change.  相似文献   
78.
The ‘reflexive turn’ transcended disciplinary boundaries within the social sciences. Feminist scholars in particular have taken up its core concerns, establishing a wide-ranging literature on reflexivity in feminist theory and practice. In this paper, I contribute to this scholarship by deconstructing the ‘story’ of my own research as a white, genderqueer, masculine-presenting researcher in Ghana. This deconstruction is based on thirteen months of field research exploring LGBT activism in the capital city of Accra. Using a series of ethnographic vignettes, I examine questions of queer subjectivity, embodiment and self/Other dynamics in the research encounter. Specifically, I interrogate what a reflexive concern for power relations means when researchers share moments of commonality and difference with research participants, here in relation to axes of gender, sexuality, race and class. Finally, I explore the challenge of theorising resistance in light of feminist postcolonial critiques of the politics of representation. I conclude that it is only by locating these tensions and dissonances in the foreground of our inquiries that reflexivity becomes meaningful as a way of rendering knowledge production more accountable and transparent, of practising feminist solidarity, and of excavating our own queer research journeys.  相似文献   
79.
Persistent underperformance of public policy and program implementation in Aboriginal affairs is widely recognised. We analysed the results of two case studies of attempted reforms in public administration of Aboriginal primary health care in the Northern Territory, using a framework based on the institutionalist and systemic racism literatures, with the aim of better understanding the sources of implementation failure. Implementation of the agreed reforms was unsuccessful. Contributing factors were as follows: strong recognition of the need for change was not sustained; the seeds of change, present in the form of alternative practices, were not built on; there was a notable absence of sustained political/bureaucratic authorisation; and, interacting with all of these, systemic racism had important consequences and implications. Our framework was useful for making sense of the results. It is clear that reforms in Aboriginal affairs will require government authorities to engage with organisations and communities. We conclude that there are four requirements for improved implementation success: clear recognition of the need for change in ‘business as usual’; sustainable commitment and authorisation; the building of alternative structures and methods to enable effective power sharing (consistent with the requirements of parliamentary democracy); and addressing the impact of systemic racism on decision-making, relationships, and risk management.  相似文献   
80.
Housework and childcare have been considered mechanisms for ‘doing gender’ through the allocation of different functions to women and to men. Women continue to devote more time and effort to this type of work, in spite of their progressive incorporation into the labour market. Same-sex couples escape this gender binarism, and so this study set out to learn the distribution criteria work, as well as the influence of gender socialization when it comes to establishing this distribution. A qualitative investigation was carried out with 21 Spanish same-sex families. The results indicate that the majority of couples position themselves in an egalitarian discourse based on the absence of differentiated gender roles and a low level of specialization. No differences were found between male and female couples. Nevertheless, the female couples show higher levels of discontent when the distribution was not egalitarian. In conclusion, it is proposed that the effects of gender socialization are perpetuated beyond heterosexual relationships and also affect same-sex couples.  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