全文获取类型
收费全文 | 873篇 |
免费 | 57篇 |
专业分类
各国政治 | 77篇 |
工人农民 | 89篇 |
世界政治 | 82篇 |
外交国际关系 | 47篇 |
法律 | 447篇 |
中国共产党 | 1篇 |
中国政治 | 6篇 |
政治理论 | 179篇 |
综合类 | 2篇 |
出版年
2024年 | 3篇 |
2023年 | 6篇 |
2022年 | 6篇 |
2021年 | 9篇 |
2020年 | 31篇 |
2019年 | 41篇 |
2018年 | 53篇 |
2017年 | 59篇 |
2016年 | 59篇 |
2015年 | 29篇 |
2014年 | 50篇 |
2013年 | 150篇 |
2012年 | 35篇 |
2011年 | 39篇 |
2010年 | 34篇 |
2009年 | 31篇 |
2008年 | 24篇 |
2007年 | 30篇 |
2006年 | 23篇 |
2005年 | 37篇 |
2004年 | 27篇 |
2003年 | 36篇 |
2002年 | 26篇 |
2001年 | 8篇 |
2000年 | 8篇 |
1999年 | 3篇 |
1998年 | 7篇 |
1997年 | 7篇 |
1996年 | 9篇 |
1995年 | 9篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1992年 | 3篇 |
1991年 | 6篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有930条查询结果,搜索用时 15 毫秒
851.
Sanchez JJ Brión M Parson W Blanco-Verea AJ Børsting C Lareu M Niederstätter H Oberacher H Morling N Carracedo A 《Forensic science international》2004,140(2-3):241-250
In the present study, we demonstrate that two commonly used Y-chromosome single nucleotide polymorphisms (SNPs), P25 and 92R7, are paralogous sequence variants (PSVs) originating from segmental duplications and that at least one of the sequence variants in each group of loci is polymorphic. Several methodologies were used in order to detect the SNP alleles and the PSVs of the loci. All results obtained with the various typing techniques supported the conclusion. The allele distributions of the binary markers were analysed in more than 600 males with seven different haplogroups. For P25, the ancestral allele C was found in several samples from different haplogroups. The derived allele A was always present with an additional C variant. Haplogroup P was defined by the derived allele A at the 92R7 locus. However, the ancestral allele G was always associated with an A variant due to the duplication. 相似文献
852.
Michelle Wood Marleen Laloup Maria del Mar Ramirez Fernandez Kevin M. Jenkins Michael S. Young Jan G. Ramaekers Gert De Boeck Nele Samyn 《Forensic Science International Supplement Series》2005,150(2-3):227
We present a validated method for the simultaneous analysis of basic drugs which comprises a sample clean-up step, using mixed-mode solid-phase extraction (SPE), followed by LC–MS/MS analysis. Deuterated analogues for all of the analytes of interest were used for quantitation. The applied HPLC gradient ensured the elution of all the drugs examined within 14 min and produced chromatographic peaks of acceptable symmetry. Selectivity of the method was achieved by a combination of retention time, and two precursor-product ion transitions for the non-deuterated analogues. Oral fluid was collected with the Intercept®, a FDA approved sampling device that is used on a large scale in the US for workplace drug testing. However, this collection system contains some ingredients (stabilizers and preservatives) that can cause substantial interferences, e.g. ion suppression or enhancement during LC–MS/MS analysis, in the absence of suitable sample pre-treatment. The use of the SPE was demonstrated to be highly effective and led to significant decreases in the interferences. Extraction was found to be both reproducible and efficient with recoveries >76% for all of the analytes. Furthermore, the processed samples were demonstrated to be stable for 48 h, except for cocaine and benzoylecgonine, where a slight negative trend was observed, but did not compromise the quantitation. In all cases the method was linear over the range investigated (2–200 μg/L) with an excellent intra-assay and inter-assay precision (coefficients of variation <10% in most cases) for QC samples spiked at a concentration of 4, 12 and 100 μg/L. Limits of quantitation were estimated to be at 2 μg/L with limits of detection ranging from 0.2 to 0.5 μg/L, which meets the requirements of SAMHSA for oral fluid testing in the workplace. The method was subsequently applied to the analysis of Intercept® samples collected at the roadside by the police, and to determine MDMA and MDA levels in oral fluid samples from a controlled study. 相似文献
853.
854.
855.
This paper focuses on the analysis of wage-price relationships during the period 1980–1991 in Poland. The dynamics of wage and price series under radical structural changes are examined, as well as the impact of earlier sharp price increases. The process of wages-to-prices adjustment both in the long- and short-term is analysed. The hypothesis that the introduction of economic reform (at the beginning of 1990) would result in a tendency towards the stabilization of real wages is investigated. This is done through integration and cointegration analysis of wage and price series with special attention being paid to the problems arising from theI(2) character of the variables investigated. The concept of polynomial cointegration is applied to formulate error correction terms for the short-run model of wages. The computations have been made using quarterly data. The results reflect an inhomogeneity of the period investigated, especially the effects of the introduction of economic reform at the beginning of 1990. The nonstationarity of real wages is confirmed, but not their tendency towards stabilization. 相似文献
856.
857.
John R. Lutzker Kathryn M. Bigelow Ronald M. Doctor Maria Lynn Kessler 《Journal of family violence》1998,13(2):163-185
This paper describes Project SafeCare, an ecobehavioral research and treatment project with families reported or at risk for child abuse or neglect. Preliminary demographic data are reviewed along with indirect assessment data. Four case studies are described to exemplify the effects of training provided to families. The implications for the current assessment data, treatment, and outcome are discussed. 相似文献
858.
Grace R. Kalfus Joseph R. Ferrari Patricia Arean David Balser Rose Cotronea Maria Franco William Hill 《Law and human behavior》1987,11(1):63-67
On January 1, 1985, the mandatory seat belt law went into effect in New York State; violators were now subject to a fine of $50.00. Police officers issued nonpenalty-based warnings during the month prior to the law's imposition. The purpose of the present study was to compare the effects of the warning versus the fine and a fine-plus-prompt condition (the prompt delivered by the experimenters) on seat belt use on a university campus. Results indicated that significantly more drivers used their sear belts during the fine conditions as compared with the warning condition and that significantly more female drivers used their seat belt during all conditions. A significant difference was not found, however, between the fine and fine-plus-prompt conditions.We gratefully acknowledge the comments of Michael Leippe on an earlier draft of this manuseript. 相似文献
859.
Chang?Woon?NamEmail author Doina?Maria?Radulescu 《Economic Change and Restructuring》2004,37(2):99-123
Not only a large number of developing countries but also transition economies have established free economic zones (FEZs) with the aim of attracting foreign capital by providing tax incentives, creating employment opportunities, and promoting exports and regional development. Tax investment promotion schemes include profit tax exemption, free or accelerated depreciation, investment tax allowance, subsidy for investment costs, etc., the effects of which on firms’ investment decisions can be compared based on the net present value model. This study suggests that even a low corporate tax rate combined with generous depreciation rules does not provide incentives for investors when the inflation rate is high. A case study on Najin–Sonbong FEZ in North Korea delivers a wide range of more crucial economic and political reasons why such a development project can fail, although tax concessions offered there are more favourable than those in China and other Asian nations. 相似文献
860.