全文获取类型
收费全文 | 7149篇 |
免费 | 215篇 |
专业分类
各国政治 | 235篇 |
工人农民 | 244篇 |
世界政治 | 481篇 |
外交国际关系 | 214篇 |
法律 | 4892篇 |
中国政治 | 47篇 |
政治理论 | 1214篇 |
综合类 | 37篇 |
出版年
2020年 | 92篇 |
2019年 | 112篇 |
2018年 | 131篇 |
2017年 | 161篇 |
2016年 | 162篇 |
2015年 | 109篇 |
2014年 | 160篇 |
2013年 | 644篇 |
2012年 | 170篇 |
2011年 | 186篇 |
2010年 | 159篇 |
2009年 | 156篇 |
2008年 | 187篇 |
2007年 | 214篇 |
2006年 | 222篇 |
2005年 | 179篇 |
2004年 | 185篇 |
2003年 | 201篇 |
2002年 | 164篇 |
2001年 | 314篇 |
2000年 | 291篇 |
1999年 | 220篇 |
1998年 | 85篇 |
1997年 | 69篇 |
1996年 | 75篇 |
1995年 | 68篇 |
1994年 | 76篇 |
1993年 | 62篇 |
1992年 | 141篇 |
1991年 | 153篇 |
1990年 | 136篇 |
1989年 | 155篇 |
1988年 | 134篇 |
1987年 | 149篇 |
1986年 | 134篇 |
1985年 | 152篇 |
1984年 | 118篇 |
1983年 | 139篇 |
1982年 | 93篇 |
1981年 | 93篇 |
1980年 | 69篇 |
1979年 | 99篇 |
1978年 | 74篇 |
1977年 | 66篇 |
1976年 | 57篇 |
1975年 | 46篇 |
1974年 | 57篇 |
1973年 | 59篇 |
1971年 | 50篇 |
1970年 | 46篇 |
排序方式: 共有7364条查询结果,搜索用时 31 毫秒
261.
A report is given of two young people who died after intake of dextromethorphan, one by suicide and the other for uncertain reasons. To our knowledge this is the first reported fatal intoxications with this drug. 相似文献
262.
Signs of hypothermia injury were studied in rabbits cooled to a core temperature of 30 degrees C by immersion in ice water and thereafter rewarmed to 35 degrees C. Anaesthetized control rabbits were kept normothermic (37 degrees C) for a corresponding time (4 h). Creatine phosphokinase (CPK) activity increased 24 h after hypothermia to 20-fold in serum. In cerebrospinal fluid the activity was already significantly (5-fold) increased after hypothermia and was still as high at 24 h. Smaller increase was also found in the control normothermic rabbits both in serum (10-fold) and cerebrospinal fluid (2-fold). The values had returned to the initial level after 1 week. Small haemorrhages were observed in the brain at 24 h and slight scarring was seen in the myocardium of some rabbits which had lived 4 weeks following hypothermia. The results indicate that CPK can be a useful marker in the diagnostics of hypothermia death, especially in cerebrospinal fluid, which is less affected than blood by autolysis. 相似文献
263.
Adolescent romantic relationships have the potential to affect psychological functioning well into adulthood. This study assessed adolescent romantic relationship qualities as long-term predictors of psychological functioning utilizing a longitudinal multi-method, multi-informant study of 80 participants (59% female; 54% Caucasian, 35% African American, 11% mixed or other race) assessed at age 17 along with their romantic partners and at ages 25–27. Controlling for gender, family income, and baseline mental health, partner-reported hostile conflict at age 17 predicted relative increases in internalizing behaviors from age 17 to 27. In contrast, observed teen support with their partner during a help-seeking task at age 17 predicted relative decreases in externalizing behaviors over time. The results are interpreted as suggesting qualities that may help determine whether adolescent romances have positive vs. negative long-term psychological health implications. 相似文献
264.
Dorothy L. Espelage Kathleen C. Basile Ruth W. Leemis Tracy N. Hipp Jordan P. Davis 《Journal of youth and adolescence》2018,47(9):1880-1893
The Bully-Sexual Violence Pathway theory has indicated that bullying perpetration predicts sexual violence perpetration among males and females over time in middle school, and that homophobic name-calling perpetration moderates that association among males. In this study, the Bully-Sexual Violence Pathway theory was tested across early to late adolescence. Participants included 3549 students from four Midwestern middle schools and six high schools. Surveys were administered across six time points from Spring 2008 to Spring 2013. At baseline, the sample was 32.2% White, 46.2% African American, 5.4% Hispanic, and 10.2% other. The sample was 50.2% female. The findings reveal that late middle school homophobic name-calling perpetration increased the odds of perpetrating sexual violence in high school among early middle school bullying male and female perpetrators, while homophobic name-calling victimization decreased the odds of high school sexual violence perpetration among females. The prevention of bullying and homophobic name-calling in middle school may prevent later sexual violence perpetration. 相似文献
265.
Suicide is the second leading cause of death for older adolescents and young adults. Although empirical literature has identified important risk factors of suicidal behavior, it is less understood if changes in risk factors correspond with changes in suicide risk. To address this knowledge gap, we assessed if there were different trajectories of suicidal behavior as youth transition into young adulthood and determined what time-varying risk factors predicted these trajectories. This study used four waves of data spanning approximately 13 years from the National Longitudinal Study of Adolescent Health. The sample included 9027 respondents who were 12–18 years old (M?=?15.26; SD?=?1.76) at Wave 1, 50% male, 17% Hispanic, and 58% White. The results indicated that 93.6% of the sample had a low likelihood for suicide attempts across time, 5.1% had an elevated likelihood of attempting suicide in adolescence but not young adulthood, and 1.3% had an elevated likelihood of attempting suicide during adolescence and adulthood. The likelihood of a suicide attempt corresponded with changes on depression, impulsivity, delinquency, alcohol problems, family and friend suicide history, and experience with partner violence. Determining how suicide risk changes as youth transition into young adulthood and what factors predict these changes can help prevent suicide. Interventions targeting these risk factors could lead to reductions in suicide attempts. 相似文献
266.
267.
Inclusive growth is contested yet adopted by the World Bank to reduce poverty and inequality through rapid economic growth. Research has tested inclusive growth in sectors including agriculture, but few studies apply it to tourism which is significant for many developing countries. The paper interrogates tourism-led inclusive growth: supply chains, economic linkages/leakage, ownership, employment and expenditure. It draws from fieldwork in Vietnam where tourism has rapidly developed with partial economic benefits for local communities, but does not appear to fall within the inclusive growth paradigm. It is unclear if tourism-led growth will become any more inclusive in the short-to-medium term. 相似文献
268.
Using public sector employment and corruption perception data for 72 countries across the world, this article demonstrates that despite common notion countries with “smaller” governments do not tend to have lower corruption. Under general assumptions, one can demonstrate that there is an optimal size of public sector employment corresponding to the highest capital intensity. The model has several implications: lower optimal sizes of governments for labor intensive countries and higher sizes for capital intensive ones, possibility to reduce corruption paying a cost of suboptimal output, and a higher “price” of an oversized government for labor intensive countries. 相似文献
269.
Michael P. A. Murphy 《Cambridge Review of International Affairs》2018,31(3-4):368-369
270.
AbstractThis article explores the heterogeneous effects of the migration–remittance process on the educational attainment of Nepalese children. The results suggest that when controlling for remittances, the children of more educated or informed parents suffer from parental absence, while the children of less informed parents gain from migration, implying that the migration experience helps less educated parents estimate the value of and returns to education more precisely. The results also suggest that remittances help severely credit-constrained households enrol their children in school and prevent dropouts. These remittances help households that face less severe liquidity constraints increase their investment in quality education. 相似文献