全文获取类型
收费全文 | 4750篇 |
免费 | 37篇 |
专业分类
各国政治 | 167篇 |
工人农民 | 52篇 |
世界政治 | 741篇 |
外交国际关系 | 461篇 |
法律 | 2634篇 |
中国共产党 | 75篇 |
中国政治 | 257篇 |
政治理论 | 320篇 |
综合类 | 80篇 |
出版年
2021年 | 27篇 |
2018年 | 24篇 |
2016年 | 17篇 |
2015年 | 21篇 |
2014年 | 112篇 |
2013年 | 32篇 |
2012年 | 321篇 |
2011年 | 287篇 |
2010年 | 130篇 |
2009年 | 99篇 |
2008年 | 258篇 |
2007年 | 358篇 |
2006年 | 343篇 |
2005年 | 296篇 |
2004年 | 257篇 |
2003年 | 247篇 |
2002年 | 250篇 |
2001年 | 184篇 |
2000年 | 189篇 |
1999年 | 97篇 |
1998年 | 50篇 |
1997年 | 36篇 |
1996年 | 33篇 |
1995年 | 28篇 |
1994年 | 67篇 |
1993年 | 37篇 |
1992年 | 49篇 |
1991年 | 46篇 |
1990年 | 31篇 |
1989年 | 29篇 |
1988年 | 120篇 |
1987年 | 31篇 |
1986年 | 31篇 |
1985年 | 32篇 |
1984年 | 42篇 |
1983年 | 35篇 |
1982年 | 26篇 |
1981年 | 39篇 |
1980年 | 44篇 |
1979年 | 40篇 |
1978年 | 20篇 |
1977年 | 55篇 |
1976年 | 36篇 |
1973年 | 16篇 |
1964年 | 27篇 |
1963年 | 25篇 |
1962年 | 41篇 |
1961年 | 19篇 |
1960年 | 22篇 |
1959年 | 30篇 |
排序方式: 共有4787条查询结果,搜索用时 15 毫秒
161.
162.
163.
164.
165.
166.
With increasing frequency, relatively small, fragmentary evidence thought to be osseous or dental tissue of human origin is submitted to the forensic laboratory for DNA analysis with the request for positive identification. Prior to performing DNA analysis, however, it is prudent to first perform a presumptive test or "screen" to determine whether the questioned material may be eliminated from further consideration. When material is shown not to be consistent with bone/teeth, DNA testing is not performed. When such determinations cannot be made from gross morphological features, elemental analysis can be indicative. This presumptive test is made possible by applying scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) in conjunction with an X-ray spectral database recently developed by the FBI laboratory. This database includes spectra for many different materials including known examples of bone and tooth from many different contexts and representing the full range of taphonomic conditions. Results of SEM/EDS analysis of evidence can be compared to these standards to determine if they are consistent with bone and/or tooth and, if not, then what the material might represent. Analysis suggests that although the proportions and amounts of calcium and phosphorus are particularly important in differentiating bone and tooth from other materials, other minor differences in spectral profile can also provide significant discrimination. Analysis enables bone and tooth to be successfully distinguished from other materials in most cases. Exceptions appear to be ivory, mineral apatite, and perhaps some types of corals. 相似文献
167.
Evaluation of laser desorption mass spectrometry and UV accelerated aging of dyes on paper as tools for the evaluation of a questioned document 总被引:1,自引:0,他引:1
Laser desorption mass spectrometry (LDMS) may be used for the detection and identification of dyes found in inks. Naturally-aged and artificially-aged blue and black ballpoint pen inks containing the cationic dye methyl violet were analyzed on paper. The average molecular weight of the dye sample was calculated from LD mass spectral data and plotted versus time. The resulting aging curves demonstrate that, as dye degradation increases, the average molecular weight of the dye decreases. Typical variables involved in ink aging, such as the type of paper and ink formulation, were investigated. Results show that these variables influence the rate of dye degradation. Furthermore, UV accelerated aging has been developed and tested as an alternative to thermal approaches. 相似文献
168.
McGrath J 《Rutgers law review》2002,54(3):649-684
This Article addresses the problems with our nation's cultural and legal prohibitions against certain pain management treatments. The practice of pain management has not kept pace with the many medical advances that have made it possible for physicians to ameliorate most pain. The Author notes that some patients are denied access to certain forms of treatments due to the mistaken belief that addiction may ensue. Additionally, some individuals are under-treated for their pain to a greater degree than are others. This is especially the case for our nation's prisoners. The Author contends that prisoners are frequently denied effective pain amelioration. He notes, however, that there has been improvement in medical treatment in general for prisoners due to court challenges based on the Eighth Amendment's prohibition against cruel and unusual punishment. Yet, due to the protection of qualified immunity given to jailers and prison health care providers, prisoners cannot bring a claim for negligence or medical malpractice, they must allege a violation of their constitutional rights, a significantly higher legal standard. Prisoners must meet a subjective test showing that there was a deliberate indifference to their medical needs that violates the protection of the Eighth Amendment. The Author concludes that because medical advances have made it possible to alleviate most pain suffering, withholding pain treatment or providing a less effective treatment is tantamount to inflicting pain and should be viewed as a violation of the Eighth Amendment. 相似文献
169.
170.