全文获取类型
收费全文 | 2608篇 |
免费 | 41篇 |
专业分类
各国政治 | 126篇 |
工人农民 | 62篇 |
世界政治 | 153篇 |
外交国际关系 | 66篇 |
法律 | 1918篇 |
中国政治 | 21篇 |
政治理论 | 286篇 |
综合类 | 17篇 |
出版年
2020年 | 31篇 |
2019年 | 22篇 |
2018年 | 22篇 |
2017年 | 33篇 |
2016年 | 40篇 |
2015年 | 23篇 |
2014年 | 38篇 |
2013年 | 187篇 |
2012年 | 61篇 |
2011年 | 68篇 |
2010年 | 36篇 |
2009年 | 35篇 |
2008年 | 56篇 |
2007年 | 71篇 |
2006年 | 71篇 |
2005年 | 74篇 |
2004年 | 72篇 |
2003年 | 70篇 |
2002年 | 70篇 |
2001年 | 156篇 |
2000年 | 123篇 |
1999年 | 76篇 |
1998年 | 26篇 |
1995年 | 18篇 |
1994年 | 22篇 |
1993年 | 21篇 |
1992年 | 63篇 |
1991年 | 69篇 |
1990年 | 61篇 |
1989年 | 84篇 |
1988年 | 83篇 |
1987年 | 72篇 |
1986年 | 76篇 |
1985年 | 65篇 |
1984年 | 35篇 |
1983年 | 41篇 |
1982年 | 19篇 |
1981年 | 30篇 |
1979年 | 28篇 |
1978年 | 21篇 |
1977年 | 27篇 |
1976年 | 19篇 |
1975年 | 31篇 |
1974年 | 30篇 |
1973年 | 31篇 |
1972年 | 32篇 |
1971年 | 24篇 |
1970年 | 20篇 |
1969年 | 24篇 |
1968年 | 20篇 |
排序方式: 共有2649条查询结果,搜索用时 15 毫秒
121.
There is a dearth of information on the mutual interaction between metal intoxication and adipocere formation. Herein, 40 adult female albino rats were distributed into two equal groups, one used as control while the other orally administered single dose of cadmium chloride (CdCl2) 225 mg/kg·bw (LDmin). Control group was killed by cervical dislocation. Half of dead rats of both groups were subjected for determination of iodine value and estimation of cadmium (Cd) residues while the other half of both groups were submerged in opened glass container previously filled with 4 L dechlorinated tap water kept in closed room with an open air access (one cadaver/container). Gross morphological changes of submerged cadavers were recorded weekly along the experiment. At the end of the experiment, after 3 months, samples were collected again for iodine value determination and estimation of Cd residues. The obtained results revealed the depressant effect of Cd toxicity on development of adipocere. Cd residues were found in different tissues of cadavers at time of death with the highest amount in the intestines followed by the liver and kidneys, then lungs, adipose tissue, muscles, and finally the bones. After 3 months of water submersion, tissues exhibited significant decrease in the amount of Cd residues but to a limit that was still detected. This study concluded the possibility of detection of Cd residues even after adipocere formation. Additionally, it shed light on the possibility of the interference of environmental pollution with the natural rate of decomposition especially adipocere formation. 相似文献
122.
Ahmet Içduygu 《Third world quarterly》2020,41(3):415-433
AbstractAlthough the Syrian conflict continues, local and global stakeholders have already begun to consider the return of the six million refugees, especially as neither the option of local integration in the countries of first asylum nor that of resettlement to third countries is seen as a realistic possibility. Elaborating on the return debates in Turkey, Lebanon and Jordan, we relate the politicisation of this question to the growing acceptance of the option of voluntary and involuntary repatriation in the international refugee regime as well as to policies and public opinion. We argue, based on empirical fieldwork, that any debate about the return of Syrian refugees is problematic, since the conditions of safety, voluntariness and sustainability are not fulfilled. Further, returns should not be left entirely to the individual hosting states and actors in the region but should be carried out in collaboration with representative authorities in Syria and the mediation of international organisations upon full resolution of conflict. 相似文献
123.
Gregory A. Porumbescu Meghan I. H. Lindeman Erica Ceka Maria Cucciniello 《Public administration review》2017,77(6):840-850
Voluntary policy compliance is an important yet rarely studied topic in public administration. To address the paucity of research, this article proposes and empirically tests a conceptual framework that ties policy transparency and policy understanding to voluntary policy compliance intentions. The reasoning is that the extent to which citizens understand a policy contributes to their intentions to comply with that policy. Further, the authors argue that policy transparency indirectly influences voluntary policy compliance intentions through a positive effect on citizens’ levels of policy understanding. To enhance the validity of the findings, the authors assess these relationships across two policy domains. The findings reflect an indirect positive effect of transparency on voluntary compliance occurring through policy understanding. However, this emerged only for one policy domain. These results suggest that the effects of policy transparency on policy understanding and voluntary policy compliance intentions may depend on the policy domain. 相似文献
124.
T Karlsmark H K Thomsen L Danielsen O Aalund O Nielsen K G Nielsen I K Genefke 《Forensic science international》1988,39(2):175-188
In order to establish pathological evidence in dermis for distinguishing between sequelae of electrical torture and those of other superficial injuries, the skin of eleven fully anaesthetized Danish Landrace pigs have been exposed to heat and electrical energy from either 50 Hz alternating current (a.c.) or direct current (d.c.) via 12 mm large contact knobs or via a pointed 0.5 mm large electrode (only 50 Hz a.c.). The lesions have been examined from 1 to 126 days after the injury. While heat lesions exposed to energy lower than 60 joule only gave minor changes, heat lesions exposed to more than 60 joule showed changes in both collagen fibres (basophilic or eosinophilic fibres without any birefringence or coarse cross-striation in polarized light, respectively) and dermal cells (granular cytoplasm). Areas exposed to 50 Hz a.c. via 0.5 mm. electrode showed basophilic collagen fibres and in a few biopsies on day 7 calcium salts on collagen fibres. Using 12 mm large electrodes the changes were minor, but basophilic and eosinophilic collagen fibres with no birefringence or with fine/coarse cross-striation respectively were seen. Even cells with 'vesicular nuclei' were seen on day 1 and 2 after the injury. The changes in the anode area showed resemblance to that of heat lesions (basophilic collagen fibres). Eosinophilic collagen fibres with fine densely spaced cross-striation in polarized light and 'vesicular nuclei' as well as collagen fibres with calcium salts were seen in the cathode lesions. It is concluded that the dermal changes in the cathode area are specific for electrical injury from day 1 to 14. However, earlier studies have demonstrated dermal changes specific for electrical injury at day 0 and the presence of calcified collagen fibres up to 2 months after injury. The dermal changes in anode lesions were non specific and could not be differentiated from those found in heat lesions. Alternating current lesions (50 Hz) were specific from day 1 to day 7, when the pointed electrode was used, but only in a few days when the energy was transferred via the 12-mm electrodes. 相似文献
125.
The polymorphism of the human vitamin D binding protein (Gc system) was investigated in a total of 149 sera from unrelated healthy Egyptians residing in Tanta City, Gharbiya Governorate, Nile Delta of Egypt, using isoelectric focusing (IEF) in thin-layer polyacrylamide gel followed by immunoblotting. The estimated gene frequencies were Gc1s = 0.540, Gc1f = 0.242 and Gc2 = 0.218. 相似文献
126.
This paper describes a simplified approach to calculating the Bayesian likelihood ratio for the case where two DNA single locus profiles are to be compared. It explains how the calculation allows for band shift and also for the variation in precision with molecular weight. A simple basic theory section explains the principles of the analysis but more detailed explanations are given in an advanced theory section. Experiments on substantial data collections are described which demonstrate the robustness of the method. 相似文献
127.
A small experiment is described which uses databases of Afro-Caribbeans and Caucasians to establish the quality of information that might be given to an investigator about the ethnic group of the donor of an unknown crime stain. The results show that the technique can provide qualified indications, but categoric conclusions are not, in general, feasible. An appraisal is given of the technique within the operational context. 相似文献
128.
Marcia M. Croft Maria I. Marshall Martins Odendo Christine Ndinya Naman N. Ondego Pamela Obura 《发展研究杂志》2018,54(4):758-775
Indigenous vegetables play an important role in Kenyan food security, but production is limited by poor seed quality. Traditionally, seeds have been traded through informal networks, but a new formal seed sector is emerging. This study assessed the relative potential for formal or informal seed systems to meet the need for high-quality indigenous vegetable seed. By evaluating determinants of farmers’ seed purchasing behaviour, we conclude that informal seed systems have greater potential to meet this need and should be strengthened. This study suggests that policy-makers should use context-specific data to guide decisions on seed policy. 相似文献
129.
Lorenzo-Blanco EI Unger JB Baezconde-Garbanati L Ritt-Olson A Soto D 《Journal of youth and adolescence》2012,41(10):1350-1365
The risk for depression increases as Hispanic youth acculturate to U.S. society. This association is stronger for Hispanic girls than boys. To better understand the influence of culture and family on depressive symptoms, we tested a process-oriented model of acculturation, cultural values, and family functioning. The data came from Project RED, which included 1,922 Hispanic students (53?% girls; 86?% were 14?years old; and 84?% were U.S. born) from Southern California. We used data from 9th to 11th grade to test the influence of acculturation-related experiences on depressive symptoms over time. Multi-group structural equation analysis suggested that both family conflict and cohesion were linked with depressive symptoms. Hispanic cultural values were associated with family cohesion and conflict but the strength and direction of these relationships varied across cultural values and gender. For girls and boys, familismo and respeto were associated with higher family cohesion and lower family conflict. Moreover, gender roles were linked with higher family cohesion in girls but not in boys. These results indicate that improving family functioning will be beneficial for boys' and girls' psychological well-being. This may be achieved by promoting familismo and respeto for boys and girls and by promoting traditional gender roles for girls. 相似文献
130.
David Córdova Seth J. Schwartz Jennifer B. Unger Lourdes Baezconde-Garbanati Juan A. Villamar Daniel W. Soto Sabrina E. Des Rosiers Tae Kyoung Lee Alan Meca Miguel Ángel Cano Elma I. Lorenzo-Blanco Assaf Oshri Christopher P. Salas-Wright Brandy Piña-Watson Andrea J. Romero 《Journal of youth and adolescence》2016,45(10):2164-2177