全文获取类型
收费全文 | 469篇 |
免费 | 21篇 |
专业分类
各国政治 | 36篇 |
工人农民 | 23篇 |
世界政治 | 43篇 |
外交国际关系 | 27篇 |
法律 | 317篇 |
中国政治 | 2篇 |
政治理论 | 40篇 |
综合类 | 2篇 |
出版年
2024年 | 3篇 |
2023年 | 6篇 |
2022年 | 10篇 |
2021年 | 10篇 |
2020年 | 20篇 |
2019年 | 19篇 |
2018年 | 19篇 |
2017年 | 29篇 |
2016年 | 30篇 |
2015年 | 15篇 |
2014年 | 22篇 |
2013年 | 50篇 |
2012年 | 23篇 |
2011年 | 16篇 |
2010年 | 11篇 |
2009年 | 15篇 |
2008年 | 16篇 |
2007年 | 14篇 |
2006年 | 19篇 |
2005年 | 18篇 |
2004年 | 16篇 |
2003年 | 17篇 |
2002年 | 15篇 |
2001年 | 14篇 |
2000年 | 5篇 |
1999年 | 6篇 |
1997年 | 2篇 |
1994年 | 2篇 |
1993年 | 5篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1974年 | 5篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1968年 | 2篇 |
1967年 | 2篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1964年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有490条查询结果,搜索用时 171 毫秒
101.
102.
103.
Agroecology has played a key role in helping Cuba survive the crisis caused by the collapse of the socialist bloc in Europe and the tightening of the US trade embargo. Cuban peasants have been able to boost food production without scarce and expensive imported agricultural chemicals by first substituting more ecological inputs for the no longer available imports, and then by making a transition to more agroecologically integrated and diverse farming systems. This was possible not so much because appropriate alternatives were made available, but rather because of the Campesino-a-Campesino (CAC) social process methodology that the National Association of Small Farmers (ANAP) used to build a grassroots agroecology movement. This paper was produced in a 'self-study' process spearheaded by ANAP and La Via Campesina, the international agrarian movement of which ANAP is a member. In it we document and analyze the history of the Campesino-to-Campesino Agroecology Movement (MACAC), and the significantly increased contribution of peasants to national food production in Cuba that was brought about, at least in part, due to this movement. Our key findings are (i) the spread of agroecology was rapid and successful largely due to the social process methodology and social movement dynamics, (ii) farming practices evolved over time and contributed to significantly increased relative and absolute production by the peasant sector, and (iii) those practices resulted in additional benefits including resilience to climate change. 相似文献
104.
Rocío Dánica Cóndor Antonino Scarelli Riccardo Valentini 《International Environmental Agreements: Politics, Law and Economics》2011,11(2):117-137
The three Rio Conventions—the United Nations Framework Convention on Climate Change, the Convention on Biological Diversity,
and the United Nations Convention to Combat Desertification—face the challenge to create synergies at different levels. The
objective of this article is to describe how we have assessed synergies between the Rio Conventions at the project level in
the forest sector. Since the complexity of the decision problem is high, we adopted the Multicriteria Decision Aid approach,
which can provide a broad insight into the decision problem and find a compromise solution to a problem with multidimensional
and conflicting criteria including social, economic and environmental features. The ELECTRE TRI model was used for assessing
synergies at the project level, and has been a useful tool to quantify the performance of afforestation and reforestation
projects into three categories (synergistic, reasonably synergistic, and not synergistic). For the first time, afforestation
and reforestation projects have been assessed in a comprehensive way through decision criteria that reflect global and local
interests using a non-compensatory multicriteria method. 相似文献
105.
Romão W Vaz BG Lalli PM Bueno MI Correa DN Telles VL de Castro EV Eberlin MN 《Journal of forensic sciences》2012,57(2):539-543
Using desorption/ionization techniques such as easy ambient sonic-spray ionization mass spectrometry (EASI-MS), it is possible to analyze documents of Brazilian vehicles for authenticity, providing a chemical profile directly from the surface of each document. A method for the detection of counterfeit documents is described, and the falsification procedure is elucidated. Forty authentic and counterfeit documents were analyzed by both positive and negative ion modes, EASI(±)-MS. EASI(+)-MS results identified the presence of (bis(2-ethylhexyl)phthalate plasticizer and of dihexadecyldimethylammonium biocide in both types of documents. For EASI(-)-MS results, the 4-octyloxybenzoic acid additive ([M + H](+): m/z 249) is present only in counterfeit documents. It was also found that counterfeit vehicle documents are produced via Laserjet printers. Desorption/ionization techniques, such as EASI-MS, offer therefore, an intelligent way to characterize the counterfeiting method. 相似文献
106.
The purpose of this study is to clarify the chronology of different stages of dental development, according to Demirjian, in a sample of Spanish children, which will enable us to build a database that will be used as a reference in regard to the dental development of individuals of our socio-geographic environment. In the same studied sample, a calculation of the dental age according to Demirjian was carried out. This study was conducted in a final sample consisting of 1010 orthopantograms, corresponding to Spanish children (485 boys and 525 girls) ages 2-16. Comparing the age of onset of the different stages among the children, evidence was found that girls had an earlier general development than boys. These differences were only statistically significant in teeth and concrete stages. The canine teeth revealed greater gender dimorphism, with significant differences in all stages compared with the upper canines. The method proposed by Demirjian for dental age calculation resulted in a significant overestimation of dental age in relation to the chronological age in boys (average of 0.87 years) and girls (average of 0.55 years). Data from this study may be used as reference for dental maturity, as well as a standard for estimating age in Spanish children. 相似文献
107.
During criminal investigations involving firearms, the detection of gunshot residues (GSRs) is one of the most important evidences. In the present study, a new method to identify trace evidences of GSRs, deposited around the bullet entrance hole, in different types of fabrics used as targets, is described. The experiments were carried out using a 0.38-inch caliber revolver, and 9-mm and 0.40-inch caliber pistols. Testimonies of 2.25 cm(2) of the fabrics were cut around the bullet entrance and digested with 10% nitric acid. Antimony, barium, and lead were analyzed in the remaining solution using a sector field inductively coupled plasma mass spectrometer. The concentrations of the elements were detected at levels up to few microgram per square centimeter. The use of ternary graphics allowed us to identify specific patterns of distribution for blank samples and the clear distinction between the revolver and pistols used. 相似文献
108.
Błachut D Wojtasiewicz K Krawczyk K Maurin J Szawkało J Czarnocki Z 《Forensic science international》2012,216(1-3):108-120
The synthesis of the designer drug 4-methylthioamphetamine (4-MTA) has been carried out using the well-known Leuckart reaction in four versions. The treatment of 4-methylthiophenylacetone with formamide, mixture of formamide/formic acid, ammonium formate, and mixture of ammonium formate and formic acid followed by acid hydrolysis brought about the formation of 4-MTA contaminated with a number of impurities. The gas chromatography mass-spectrometry (GC-MS) analysis of the reaction mixtures allowed identification of the most prominent impurities, such as diasteromers of N,N-di-[β-(4-methylthiophenyl)isopropyl]amine, N,N-di-[β-(4-methylthiophenyl)isopropyl]methylamine, N,N-di-[β-(4-methylthiophenyl)isopropyl]formamide, the Schiff bases derived from 4-MTA and 4-methylbenzaldehyde (benzaldimine) and 4-methylthiophenylacetone (ketimine) as well as some heterocycles: 4-methyl-5-(4'-methylthiophenyl)pyrimidine, 4-(4'-methylthiobenzyl)pyrimidine, 2,6-dimethyl-3,5-di-(4'-methylthiophenyl)pyridine, 2,4-dimethyl-3,5-di-(4'-methylthiophenyl)pyridine. The correctness of identification was confirmed by independent synthesis of these compounds. Each synthesized reference compound was characterized by means of MS, (1)H and (13)C NMR, and IR methods. The stereochemistry of (RR/SS) diasteromer of N,N-di-[β-(4-methylthiophenyl)isopropyl]amine was confirmed by a crystallographic method. 相似文献
109.
Marek Szydło 《European Law Journal》2012,18(6):793-820
The European legislator, being supported in that regard by the Court of Justice, confers upon national regulatory authorities (NRAs) the exercise of the most important tasks concerned with the regulation of the network‐bound sectors, while at the same time guarantees NRAs a far‐reaching independence in exercising of their discretionary powers and shielding NRAs against other public authorities, including national parliaments. This, in turn, raises many doubts from the perspective of some essential constitutional principles of the Member States, such as, among others, ‘the domain of the law,’ which reserves the regulation of issues sensitive to the citizens as an exclusive parliament's prerogative. It is submitted in this article that national parliaments should play a much more active role in regulating the network‐bound sectors. The main point is to strengthen the protection of fundamental rights of regulated parties and create the real democratic legitimisation of NRAs, while not undermining those regulatory objectives that are already accorded at the EU level. 相似文献
110.
Gusmão L Butler JM Carracedo A Gill P Kayser M Mayr WR Morling N Prinz M Roewer L Tyler-Smith C Schneider PM;DNA Commission of the International Society of Forensic Genetics 《Forensic science international》2006,157(2-3):187-197
The DNA Commission of the International Society of Forensic Genetics (ISFG) regularly publishes guidelines and recommendations concerning the application of DNA polymorphisms to the problems of human identification. A previous recommendation published in 2001 has already addressed Y-chromosome polymorphisms, with particular emphasis on short tandem repeats (STRs). Since then, the use of Y-STRs has become very popular, and a numerous new loci have been introduced. The current recommendations address important aspects to clarify problems regarding the nomenclature, the definition of loci and alleles, population genetics and reporting methods. 相似文献