全文获取类型
收费全文 | 1900篇 |
免费 | 94篇 |
专业分类
各国政治 | 58篇 |
工人农民 | 240篇 |
世界政治 | 107篇 |
外交国际关系 | 77篇 |
法律 | 1039篇 |
中国共产党 | 1篇 |
中国政治 | 26篇 |
政治理论 | 426篇 |
综合类 | 20篇 |
出版年
2023年 | 15篇 |
2022年 | 13篇 |
2021年 | 17篇 |
2020年 | 44篇 |
2019年 | 56篇 |
2018年 | 78篇 |
2017年 | 93篇 |
2016年 | 81篇 |
2015年 | 77篇 |
2014年 | 89篇 |
2013年 | 284篇 |
2012年 | 76篇 |
2011年 | 103篇 |
2010年 | 57篇 |
2009年 | 68篇 |
2008年 | 88篇 |
2007年 | 74篇 |
2006年 | 76篇 |
2005年 | 59篇 |
2004年 | 58篇 |
2003年 | 56篇 |
2002年 | 42篇 |
2001年 | 38篇 |
2000年 | 30篇 |
1999年 | 23篇 |
1998年 | 25篇 |
1997年 | 21篇 |
1996年 | 13篇 |
1995年 | 14篇 |
1994年 | 18篇 |
1993年 | 12篇 |
1992年 | 7篇 |
1991年 | 14篇 |
1990年 | 12篇 |
1989年 | 11篇 |
1988年 | 13篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 11篇 |
1984年 | 14篇 |
1983年 | 11篇 |
1982年 | 11篇 |
1981年 | 14篇 |
1980年 | 11篇 |
1979年 | 9篇 |
1978年 | 5篇 |
1977年 | 8篇 |
1976年 | 7篇 |
1973年 | 5篇 |
1967年 | 3篇 |
排序方式: 共有1994条查询结果,搜索用时 0 毫秒
201.
202.
Sandra H. Johnson 《The Journal of law, medicine & ethics》1995,23(3):266-272
203.
Papillary hyperplasia of the lingual tonsils is a rare entity not previously reported at autopsy. We report a case that occurred in a 19-year-old man who died suddenly from his epilepsy, associated with aspiration of gastric contents. We describe the pathological features of this unusual condition, discuss the possible significance in this case and stress the importance of routine examination of the tongue and pharynx in every autopsy. 相似文献
204.
205.
Robert T. Ammerman Jack Stevens Frank W. Putnam Mekibib Altaye Jaclyn E. Hulsmann Heather D. Lehmkuhl Jennifer C. Monroe Thomas A. Gannon Judith B. Van Ginkel 《Journal of family violence》2006,21(2):105-115
Predictors of engagement in mothers receiving home visitation in the first year of service was examined. Early engagement was studied in three ways: (1) length of time active in the program during the first year of service (duration), (2) number of visits received (quantity), and (3) gaps in service between visits (consistency). Examined visits received in 515 first-time mothers in a Healthy Families America (HFA) program. Parameters of engagement were investigated, and predictors of engagement were identified using demographics and the Kempe Family Stress Inventory. Inclusive of the Assessment Visit, 31.8% of mothers disengaged prior to the first month of service. Remaining active in the program was associated with being Caucasian, and increased parenting risk (mental health/substance abuse history, low social support, increased stress). Most mothers had fewer home visits than prescribed. Gaps in prescribed service were common, with 89.4% of mothers experiencing gaps between visits of 1 month, and dropping to 16.4% having gaps of 2 months. In contrast to findings from clinic-based interventions, early engagement in home visitation is associated with lower levels of functioning and acute needs. These findings add to a growing body of literature suggesting that increased adversity promotes engagement in prevention programs in general, and home visitation programs in particular. To the extent that mothers who are actively engaged in home visitation are likely to have increased psychosocial needs, curricula may require modification and augmentation to address these needs and optimize program effectiveness. 相似文献
206.
207.
208.
209.
210.
Ninhydrin is one of the most widely used reagents for chemical development of fingerprints on porous surfaces. The detection is based on the reaction of ninhydrin with a monoacidic component of the fingerprint to form an intensively colored compound named Ruhemann's Purple. A computational study of the mechanisms and reaction energetics of the formation of Ruhemann's Purple from ninhydrin and alanine is presented. Such a study is significant from a forensic science point of view because of the strong interest in the forensic chemistry and law enforcement communities in developing alternatives to the current generation of ninhydrin like chemicals for the detection and development of latent fingerprints. Information about the mechanism of reaction between ninhydrin and amino acids can ultimately help to design compounds with stronger chromo-fluorogenic properties in aid of detecting fingerprints at crime scenes. The three most accepted mechanisms of formation have been considered using ab initio quantum mechanical calculations. At relatively high temperature ( approximately 100 degrees C) all three mechanisms are energetically feasible. However since it is recommended that forensic analyses be performed at room temperature, a revised mechanism is proposed for the formation of Ruhemann's Purple under this condition. 相似文献