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   3273篇
  免费   206篇
各国政治   329篇
工人农民   198篇
世界政治   389篇
外交国际关系   220篇
法律   1691篇
中国共产党   1篇
中国政治   18篇
政治理论   606篇
综合类   27篇
  2023年   44篇
  2022年   30篇
  2021年   65篇
  2020年   108篇
  2019年   150篇
  2018年   183篇
  2017年   243篇
  2016年   200篇
  2015年   141篇
  2014年   182篇
  2013年   546篇
  2012年   158篇
  2011年   132篇
  2010年   85篇
  2009年   75篇
  2008年   119篇
  2007年   131篇
  2006年   113篇
  2005年   93篇
  2004年   110篇
  2003年   98篇
  2002年   73篇
  2001年   59篇
  2000年   54篇
  1999年   32篇
  1998年   28篇
  1997年   30篇
  1996年   11篇
  1995年   18篇
  1994年   10篇
  1993年   14篇
  1992年   15篇
  1991年   14篇
  1990年   7篇
  1989年   5篇
  1988年   8篇
  1987年   9篇
  1986年   6篇
  1985年   8篇
  1984年   7篇
  1983年   4篇
  1982年   6篇
  1978年   4篇
  1974年   7篇
  1972年   6篇
  1971年   4篇
  1968年   4篇
  1967年   5篇
  1966年   6篇
  1965年   4篇
排序方式: 共有3479条查询结果,搜索用时 31 毫秒
211.
Two species of blow flies (Diptera: Calliphoridae) were reared on tissues from rabbits administered different dosages of morphine. These species, Protophormia terraenovae and Calliphora vicina are among the first wave of insects colonizing a dead body. Two series of 3 rabbits were given dosages of 10, 20, and 40 mg/h of morphine over a 3 h period via ear artery perfusion. A morphine blood level plateau was attained after 1 h of perfusion. Two other rabbits were used as controls. Samples of tissues collected from rabbits using a coelioscopic technique were determined to have morphine concentrations similar to those encountered in human overdoses and were correlated with dosages of morphine administered. All samples from control rabbits were negative for morphine. Larvae and puparia of both species were regularly collected from each rabbit for toxicological analysis. Concentrations of morphine in larvae reared on rabbit carcasses containing morphine were significantly lower than concentrations found in the tissues. There was a decrease in concentration in morphine observed in transition from feeding 3rd instar larva to puparium. A correlation between larval concentration and tissue concentration was found only in feeding 3rd instar larvae.  相似文献   
212.
Initially Norwegian climate policy was very ambitious and Norway stood forth as a pusher on the international scene. Over time Norwegian policy has become more sober, stressing the need for differentiated commitments and flexible implementation. In contrast to the initial enthusiastic phase, climate change policy has been increasingly seen in pragmatic economic terms. Still, Norway is no laggard, as it has shown more willingness to pay for abatement measures than many other countries.  相似文献   
213.
The use of commercial explosives is an unusual method of commiting suicide, and only a few cases have been described in the medicolegal literature. In this paper, two cases of suicide are considered that reflect backgrounds of financial problems and psychological illnesses, respectively. Both individuals comitted suicide by detonating an explosive (fireworks). In the first case putting the explosive on his head and in the second case into his mouth. In both cases the cause of death was the destruction of the central nervous system. The following cases emphasize the importance of the forensic pathologist in the recognition of the scene, as well as the systematical collection of trace evidence of the explosion for their subsequent study in the laboratory and their correlation with the autopsy findings.  相似文献   
214.
Morphine was detected by immunohistochemistry on sections of third stage larvae of Calliphora vomitoria (Diptera, Calliphoridae) reared on minced beef meat previously treated with morphine hydrochloride. The detection was performed with an avidin-biotin-peroxidase-complex method. Positive specimens showed specific staining of the haemolymph and a more intense immunoreaction in an area located at the limit between exocuticle and endocuticle. These results constitute an evidence of morphine accumulation inside the cuticle of Diptera larvae during their development. During the pupariation, the larval cuticle is transformed into the sclerotized puparium. This study consequently points out the possibilities of analyzing empty pupariae when suitable tissues or living necrophagous insects are absent.  相似文献   
215.
Diabetes mellitus is a chronic metabolic illness responsible for a great number of deaths. In postmortem diagnosis, because of the difficulty involved in interpreting blood glucose levels and relatively nonspecific pathologic features, biochemical markers in vitreous humor are useful. The aim of this study was to compare the results obtained for the combined determination of lactate and glucose with fructosamine levels recorded in the vitreous humor of two diagnostic groups (one diabetic and the other nondiabetic). The authors intended to ascertain the capacity of different markers measured in vitreous humor to diagnose diabetes mellitus. Fifty-one cadavers (mean age, 58.7 years; standard deviation, 17.09) were studied. The mean postmortem interval was 16.4 hours (standard deviation, 9.05). Cases were assigned to two diagnostic groups according to whether they were previously diagnosed as either diabetic or nondiabetic. Statistically significant differences for glucose, fructosamine, and the sum values of glucose and lactate were found between the two diagnostic groups. The highest levels were obtained in the group of cases with a previous diagnosis of diabetes mellitus. After the comparison of receiver operating characteristic curves, the sum values of glucose and lactate in vitreous humor is a better predictor of antemortem diabetes mellitus than the fructosamine.  相似文献   
216.
1-Aryl-piperazine compounds are, depending on their substituents, selective for certain serotonin receptors and together with their easy availability and their so-called legal status, this group of psychoactive compounds are potential designer drugs-of-abuse. Internet in that respect is an important source of information and distribution facilities. Because this development may have consequences for the interpretation of future clinical and forensic toxicological case studies, some analytical aspects of 1-benzyl-piperazine (BZP), 1-[4-methoxyphenyl]-piperazine (pMeOPP) and 1-[3-trifluoromethylphenyl]-piperazine (TFMPP) were studied. BZP was not detected by the AxSYM FPIA technology designed to determine amphetamine-like compounds, but had showed some cross reactivity with EMIT d.a.u.. The cross reactivities at 300 and 12,000ng/ml (RS)-amphetamine equivalents were 0.4 and 1.3%, respectively. Although BZP was not identified directly by the REMEDi HS Drug Profiling System, it can be detected by this HPLC/UV scanning system. Using GC/NPD without derivatisation, BZP, pMeOPP and TFMPP can be analysed for and applying GC/MS without or with acetylation or trifluoroacetylation, these compounds can be identified unambiguously. The usefulness of GC/NPD and GC/MS in this respect was demonstrated by the quantitative and qualitative analysis of the content of a capsule with the synthetic stimulant A2, which proved to contain 86.4mg of BZP.  相似文献   
217.
The use of the LightCycler for the detection of Y chromosome SNPs   总被引:3,自引:0,他引:3  
A novel methodology based on PCR monitoring on-line with fluorescent formats using the LightCycler for Y chromosome SNP typing is proposed. The main advantages of the system are the time necessary for the analysis (which is around 20 min), the robustness and the accuracy of the method and especially its sensitivity, which permits the detection of the male component in male-female mixtures up to 1:300 for some of the SNPs.Singleplexes of four different SNPs (M9, sY81, SRY-1532 and SRY-2627) as well as two duplexes (M9 and sY81 on the one hand and SRY-1532 and SRY-2627 on the other) were efficiently implemented. A simultaneous amplification and analysis of the four SNPs is also possible. It seems difficult with the current methodology to implement more than a quadruplex.  相似文献   
218.
219.
Since the suicide—homicide of 53 members of the Order of the Solar Temple in 1994 and the gas attempt by Aum Shinrikyo in Tokyo's subway in 1995, a number of European states have decided to fight against sects. France and Belgium are in the forefront of this battle. Both countries have set up official observatories of sects and state agencies involving various ministries to combat them. Preventive policies targeting sects are being carried out. In Belgium, the Anthroposophic Society, a philosophical movement listed as 1 of 189 sects suspected of being dangerous, has sued one federal entity that printed unfounded accusations against their movement in a widely distributed brochure against sects. The same Anthoposophic Society has also petitioned the Court of Arbitration to have the law establishing an observatory of sects annuled. This report deals with both legal actions.  相似文献   
220.
Why do people vote? An experiment in rationality   总被引:1,自引:0,他引:1  
Blais  André  Young  Robert 《Public Choice》1999,99(1-2):39-55
The study presents the findings of an experiment conducted during the 1993 Canadian fedeal election campaign. Students in two universities were exposed to a ten-minute presentation about the rational model of voting and the ‘paradox’ that so many people vote when it is apparently irrational on a cost-benefit basis. Our data indicate that exposure to the presentation decreased turnout in the election by seven percentage points. This result contributes to the debate abut the effect of rational-choice models on real political behavior. More important, the experimental panel data permit the presentation's effect to be decomposed, and this helps explain why people do vote. In this study, turnout was reduced mainly because the presentation diminished the respondents' sense of duty, an effect that was indirect, because there was no reference in the presentation to such motives. Framing the voting act in rational-choice terms induced some students to reconsider whether they should feel obliged to vote.  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