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   1085篇
  免费   55篇
各国政治   62篇
工人农民   66篇
世界政治   81篇
外交国际关系   74篇
法律   532篇
中国政治   7篇
政治理论   299篇
综合类   19篇
  2023年   4篇
  2022年   5篇
  2021年   11篇
  2020年   21篇
  2019年   26篇
  2018年   40篇
  2017年   52篇
  2016年   45篇
  2015年   30篇
  2014年   44篇
  2013年   165篇
  2012年   39篇
  2011年   39篇
  2010年   22篇
  2009年   22篇
  2008年   36篇
  2007年   46篇
  2006年   45篇
  2005年   34篇
  2004年   42篇
  2003年   32篇
  2002年   19篇
  2001年   20篇
  2000年   27篇
  1999年   13篇
  1998年   11篇
  1997年   17篇
  1996年   11篇
  1995年   11篇
  1994年   14篇
  1993年   9篇
  1992年   6篇
  1991年   14篇
  1990年   8篇
  1989年   13篇
  1988年   12篇
  1987年   6篇
  1986年   6篇
  1985年   9篇
  1984年   12篇
  1983年   10篇
  1982年   11篇
  1981年   12篇
  1980年   11篇
  1979年   9篇
  1978年   6篇
  1977年   6篇
  1976年   6篇
  1973年   7篇
  1972年   4篇
排序方式: 共有1140条查询结果,搜索用时 31 毫秒
81.
Poppy seeds contain morphine in different amounts. Reported concentrations are up to 294 mg morphine/kg poppy seeds. Since penalties based on Street Traffic Law (parapgraph 24a StVG) in Germany (administrative offence) require definitive proof of morphine in blood samples, and the "Grenzwertkommission" in consultation with the Ministry of Transportation recommended a threshold of free morphine of 10 ng/mL, the question arose whether the consumption of poppy seeds can lead to a blood concentrations equal or higher than 10 ng/mL of free morphine. Therefore, five volunteers ate poppy seed products (50 mg morphine/kg poppy seeds). In urine, all on-site tests were enzyme immunologically positive for opiates and were positive to morphine by GC/MS. All the blood samples were negative to morphine by EIA and to free morphine by GC/MS. However, after hydrolysis, morphine was detected by GC/MS in all cases. Accordingly, in Germany, penalties based on parapgraph 24a StVG are not likely to cause road users any concerns should they have consumed poppy seeds. Driver Licensing Authorities, however, should be advised of this problem to avoid unjustified legal measures.  相似文献   
82.
Already the Celts and ancient Germanic peoples knew about the poisonousness of the yew, which played an important part in the mythology of these civilizations. For hunting, the arrows were made poisonous with yew juice, and yew leaves were used for homicide and suicide. In modern times taxine is rarely used with suicidal intent, although this method is actually recommended on the respective Websites. After a 14-year-old boy had intensively studied poisonous plants and methods of suicide on various Websites, he cut leaves from a yew tree (taxus baccata) in his parents' garden, crushed and ingested them and died soon afterwards. At the forensic autopsy pieces of the partially crushed, partially completely preserved yew leaves were found in the stomach. The histological findings were unspecific, e.g. marked general blood congestion of the internal organs and pronounced cerebral and pulmonary edema. When the tree leaves found in the stomach were viewed under the light microscope, a stoma typical of taxus was observed; chemical-toxicological investigations revealed 3,5-dimethoxyphenol in the gastric content, which is considered a marker for the ingestion of taxus.  相似文献   
83.
Diphenhydramine is an antihistamine available in numerous over-the-counter preparations. Often used for its sedative effects in adults, it can cause paradoxical central nervous system stimulation in children, with effects ranging from excitation to seizures and death. Reports of fatal intoxications in young children are rare. We present five cases of fatal intoxication in infants 6, 8, 9, 12, and 12 weeks old. Postmortem blood diphenhydramine levels in the cases were 1.6, 1.5, 1.6, 1.1 and 1.1 mg/L, respectively. Anatomic findings in each case were normal. In one case the child's father admitted giving the infant diphenhydramine in an attempt to induce the infant to sleep; in another case, a daycare provider admitted putting diphenhydramine in a baby bottle. Two cases remain unsolved; one case remains under investigation. The postmortem drug levels in these cases are lower than seen in adult fatalities. We review the literature on diphenhydramine toxicity, particularly as it pertains to small children, and discuss the rationale for treating these cases as fatal intoxications.  相似文献   
84.
Fighting for air     
Johnson D 《Newsweek》2003,142(12):54
  相似文献   
85.
The present research was designed to examine factors associated with career and marriage orientations in male and female college students. The first phase of the research identified qualitatively different factors associated with variations in life structure. Respondents completed an open-ended questionnaire which elicited the perceived consequences and normative pressures concerning three life structure alternatives: (a) emphasizing career, (b) emphasizing marriage, and (c) placing equal emphasis on career and mariage. A set of 24 concerns was identified, and sex differences on several of these dimensions were noted. In general, the data were consistent with previous analyses of value structures in adults. The second phase of the research used a quantitative approach to examine the three life structure alternatives. Males and females did not differ in the relative emphasis they intended to give to career and marriage. However, sex differences in the perceived consequences of the life structure alternatives were noted.This research was conducted while the first author was a National Research Service Award (NIMH) trainee, Grant No. 1 T32 MH14593. A modified version of this paper was presented at the 87th Annual Convention of the American Psychological Association, New York, september 1979.Current research interest is psychosocial development during the adult years.Received Ph.D. from the University of Illinois, 1976. Current research interest is attitude theory and measurement.  相似文献   
86.
Despite the persistent efforts of federal tax policymakers to place binding constraints on the economic development bond market in the United States, it has grown since the Tax Reform Act of 1986 and is a well established segment of the municipal securities market. This article provides an analysis of the development bond market by describing tax increment debt finance (TIF) in the United States and conducting an empirical analysis of California TIF debt. Our analysis indicates that tax increment debt finance (TIF) is no longer an obscure infrequently used financing tool, but for local governments in many states is a commonly used means of raising capital for multiple purposes. Our empirical analysis highlights the unique project-specific features of tax increment finance that bond issuers must understand and manage to enhance the credit quality and minimize the financing costs of tax increment debt.  相似文献   
87.
Health care reform became a premier issue on the U.S. policy agenda in the 1990s. While the comprehensive proposal put forth by President Clinton failed, states and the federal government successfully pursued a variety of lesser initiatives. This article focuses on a set of reforms intended to make private health insurance more accessible and affordable to individuals and workers in small firms. It outlines the key arguments made by experts to justify stronger regulation of health insurance and the options and difficult tradeoffs that must be considered in policy design. It then examines the scope and strength of legislation adopted by 45 states and the federal government from 1990 to 1996. The substantial variation in state policies demonstrates that even though insurance market reform was the one issue that commanded nearly universal support in the health care debate, few design features were universally accepted by those who crafted the reforms. The article concludes by assessing the pattern of state and federal action. The reforms represent some progress on nominal access to insurance but little progress on the affordability of insurance for individuals and small groups. Few of the reforms present a serious challenge to existing practices and interests of the insurance industry. This pattern of policy design reflects the logical and political constraints of incrementalism. In a system where insurance coverage is voluntary, changes to increase access for one group tend to increase costs and thereby decrease access for another segment of the population. In addition, because incremental reforms will not attract sustained attention and support from the general public, it is politically difficult to impose substantial new regulation on a powerful industry.  相似文献   
88.
89.
90.
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