全文获取类型
收费全文 | 512篇 |
免费 | 30篇 |
专业分类
各国政治 | 15篇 |
工人农民 | 66篇 |
世界政治 | 94篇 |
外交国际关系 | 10篇 |
法律 | 246篇 |
中国政治 | 7篇 |
政治理论 | 98篇 |
综合类 | 6篇 |
出版年
2024年 | 1篇 |
2023年 | 6篇 |
2022年 | 3篇 |
2021年 | 7篇 |
2020年 | 15篇 |
2019年 | 16篇 |
2018年 | 28篇 |
2017年 | 28篇 |
2016年 | 16篇 |
2015年 | 20篇 |
2014年 | 14篇 |
2013年 | 49篇 |
2012年 | 30篇 |
2011年 | 15篇 |
2010年 | 12篇 |
2009年 | 10篇 |
2008年 | 35篇 |
2007年 | 39篇 |
2006年 | 24篇 |
2005年 | 30篇 |
2004年 | 17篇 |
2003年 | 20篇 |
2002年 | 15篇 |
2001年 | 9篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 6篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 7篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 6篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 10篇 |
1984年 | 3篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有542条查询结果,搜索用时 10 毫秒
91.
92.
The early stages of adoptive placements are important in achieving successful long-term outcomes for adopted children and their families. This paper reports on findings from the Wales Adoption Study, in which adoptive parents shared their views and experiences of the legal and administrative processes in obtaining an adoption order. Parents described a range of difficulties that added to anxieties and delays. These arose mainly through poor communication about the steps in the legal process and avoidable administrative errors or oversights. Some parents also experienced lack of information and support regarding agreed contact arrangements and work with their child to help them make sense of their adoptive status. 相似文献
93.
Mental health,substance use,and offending patterns among Native American youth in juvenile detention
Research has shown that youthful offenders in the juvenile justice system report an array of substance use and emotional and other mental health needs. The current study closely examined these issues in a large national sample (n = 539) of Native American youth drawn from the Survey of Youth in Residential Placement. Results demonstrated that frequent substance use was associated with the likelihood of being detained for a drug offense, while emotional and mental health needs were associated with detention for the most serious offenses. These results highlight the need for comprehensive substance use and other mental health assessments for Native American youth in the juvenile justice system. 相似文献
94.
95.
Larry J. Nelson Laura M. Padilla-Walker Katherine J. Christensen Cortney A. Evans Jason S. Carroll 《Journal of youth and adolescence》2011,40(6):730-743
The changing nature of the transition to adulthood in western societies, such as the United States, may be extending the length
of time parents are engaged in “parenting” activities. However, little is known about different approaches parents take in
their interactions with their emerging-adult children. Hence, this study attempted to identify different clusters of parents
based on the extent to which they exhibited both extremes of control (psychological control, punishment, verbal hostility,
indulgence) and responsiveness (knowledge, warmth, induction, autonomy granting), and to examine how combinations of parenting
were related to emerging adult children’s relational and individual outcomes (e.g. parent–child relationship quality, drinking,
self-worth, depression). The data were collected from 403 emerging adults (M age = 19.89, SD = 1.78, range = 18–26, 62% female) and at least one of their parents (287 fathers and 317 mothers). Eighty-four
percent of participants reported being European American, 6% Asian American, 4% African American, 3% Latino, and 4% reported
being of other ethnicities. Data were analyzed using hierarchical cluster analysis, separately for mothers and fathers, and
identified three similar clusters of parents which we labeled as uninvolved (low on all aspects of parenting), controlling-indulgent (high on both extremes of control and low on all aspects of responsiveness), and authoritative (high on responsiveness and low on control). A fourth cluster was identified for both mothers and fathers and was labeled
as inconsistent for mothers (mothers were above the mean on both extremes of control and on responsiveness) and average for fathers (fathers were at the mean on all eight aspects of parenting). The discussion focuses on how each of these clusters
effectively distinguished between child outcomes. 相似文献
96.
97.
Gerostamoulos D Beyer J Wong K Wort C Drummer OH 《Forensic science international》2011,205(1-3):69-72
Blood was available for the estimation of carboxyhemoglobin saturation (COHb) in 30 of the 173 persons who died in the Victorian bushfires in February 2009. The ages of these 30 deaths ranged from 3 to 80 years and there were 8 females. 13 cases (43%) were considered negative (less than 5% COHb), 12 (40%) were between 5 and 40% COHb, 2 (6.7%) between 40 and 50% and 3 (10%) were greater than 50% COHb. There were 6 persons either found within a building or a car and the COHb in these cases ranged up to 69% (mean 50%). There were 5 cases where the location was unable to be determined as either indoor or outdoor due to the extensive nature of the fire. The remaining 19 deceased persons were all located outside in the open and the concentration of COHb in these cases ranged up to 30% (mean 19%). Hydrogen cyanide was only detected in two deceased persons at concentrations of 0.5 and 2.7 mg/L, respectively. 13 deceased were found to have soot in the airways following necropsy but this did not correlate with the COHb levels. 相似文献
98.
99.
Mahfouz M Badawi A Merkl B Fatah EE Pritchard E Kesler K Moore M Jantz R Jantz L 《Forensic science international》2007,173(2-3):161-170
Sex determination is one of the essential steps in personal identification of an individual from skeletal remains. Most elements of the skeleton have been subjected to discriminant function analysis for sex estimation, but little work has been done in terms of the patella. This paper proposes a new sex determination method from the patella using a novel automated feature extraction technique. A dataset of 228 patellae (95 females and 133 males) was amassed from the William M. Bass Donated Skeletal Collection from the University of Tennessee and was subjected to noninvasive high resolution computed tomography (CT). After the CT data were segmented, a set of features was automatically extracted, normalized, and ranked. The segmentation process with surface smoothing minimizes the noise from enthesophytes and ultimately allows our methods to distinguish variations in patellar morphology. These features include geometric features, moments, principal axes, and principal components. A feature vector of dimension 45 for each subject was then constructed. A set of statistical and supervised neural network classification methods were used to classify the sex of the patellar feature vectors. Nonlinear classifiers such as neural networks have been used in previous research to analyze several medical diagnosis problems, including quantitative tissue characterization and automated chromosome classification. In this paper, different classification methods were compared. Classification success ranged from 83.77% average classification rate using labels from a Fuzzy C-Means (FCM) clustering step, to 90.3% for linear discriminant classification (LDC). We obtained results of 96.02% and 93.51% training and testing classification rates, respectively, using feed-forward backpropagation neural networks (NN). These promising results using newly developed features and the application of nonlinear classifiers encourage the usage of these methods in forensic anthropology for identifying the sex of an individual from incomplete skeletons retaining at least one patella. 相似文献
100.
This study examines the amplification success rate of mitochondrial DNA from human head hair with respect to their potential for forensic application. Mitochondrial DNA was isolated using a Chelex-based extraction method and amplified using the LINEAR ARRAY duplex PCR system. The particular focus of this study was to characterize the morphological features of human head hair in order to further the understanding of the factors that influence amplification success rate in hair tissue using the LINEAR ARRAY duplex PCR system. 2554 head hairs from 132 individuals representing four population groups were amplified. The hair samples were characterized as follows: 1251 were identified microscopically as telogen hairs and 1303 were classified as hairs without roots (removed before extraction). Amplification success was assessed as a function of several independent variables: morphological characteristics; telogen root versus no root; donor age; scalp origin; use of cosmetic hair treatments; and race of the donor. The results show that a positive correlation exists between amplification success and the presence of a telogen root. Combining the amplification success with either the original or optimized protocol, telogen hairs result in an overall success rate of 77.5% compared with 65% for hairs with no roots. Controlling for telogen hairs, the findings indicate that the overall success rate is independent of cosmetic hair treatments; medulla structure; shaft length, diameter, and volume; and scalp origin. Conversely, the age of the donor, the race of the donor, and hair pigmentation all contribute to a variation in amplification success rate. 相似文献