全文获取类型
收费全文 | 11578篇 |
免费 | 629篇 |
专业分类
各国政治 | 489篇 |
工人农民 | 400篇 |
世界政治 | 915篇 |
外交国际关系 | 365篇 |
法律 | 7687篇 |
中国共产党 | 4篇 |
中国政治 | 72篇 |
政治理论 | 2190篇 |
综合类 | 85篇 |
出版年
2021年 | 75篇 |
2020年 | 236篇 |
2019年 | 273篇 |
2018年 | 277篇 |
2017年 | 330篇 |
2016年 | 351篇 |
2015年 | 285篇 |
2014年 | 322篇 |
2013年 | 1139篇 |
2012年 | 290篇 |
2011年 | 356篇 |
2010年 | 325篇 |
2009年 | 346篇 |
2008年 | 326篇 |
2007年 | 295篇 |
2006年 | 310篇 |
2005年 | 296篇 |
2004年 | 294篇 |
2003年 | 269篇 |
2002年 | 278篇 |
2001年 | 490篇 |
2000年 | 449篇 |
1999年 | 304篇 |
1998年 | 201篇 |
1997年 | 152篇 |
1996年 | 131篇 |
1995年 | 126篇 |
1994年 | 153篇 |
1993年 | 136篇 |
1992年 | 199篇 |
1991年 | 224篇 |
1990年 | 208篇 |
1989年 | 221篇 |
1988年 | 209篇 |
1987年 | 192篇 |
1986年 | 238篇 |
1985年 | 207篇 |
1984年 | 162篇 |
1983年 | 175篇 |
1982年 | 115篇 |
1981年 | 121篇 |
1980年 | 86篇 |
1979年 | 132篇 |
1978年 | 76篇 |
1977年 | 74篇 |
1976年 | 71篇 |
1974年 | 77篇 |
1973年 | 67篇 |
1972年 | 69篇 |
1970年 | 47篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
871.
872.
Bohnert M Faller-Marquardt M Lutz S Amberg R Weisser HJ Pollak S 《Forensic science international》2001,116(2-3):107-115
In hanging and ligature strangulation, the noose mostly causes a mark or groove which is formed partly by compression of the skin and partly by abrasion with loss of the upper epidermal layers. The horny scales abraded from the neck may be transferred to the strangulation device or to the interposed textiles where they are sometimes visible at stereomicroscopic examination or even to the naked eye as silver-grey particles. The morphologic features of the epidermal transfer due to hanging and ligature strangulation is demonstrated by 14 case examples. The biological traces may be sufficient for comparative DNA typing by means of PCR-based methods. In 9 out of the 14 cases, genomic DNA typing was successful. Analysis of mtDNA succeeded in another two cases, although genomic DNA could not be detected. Beside the accumulation of solid epidermic particles the paper describes deposition of serous and fatty tissue fluid at the ligature (mainly adjacent to skin ridges). 相似文献
873.
874.
Grattapaglia D Schmidt AB Costa e Silva C Stringher C Fernandes AP Ferreira ME 《Forensic science international》2001,118(1):91-94
Allele frequencies for the 13 STR core loci (D3S1358, VWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820, CSF1PO, TPOX, THO1 and D16S539) included in the AmpFlSTR((R)) Profiler Plus and AmpFlSTR((R)) Cofiler kits were obtained for a sample of 700-800 genetically unrelated Brazilians. The expected performance of these loci for personal identification and paternity testing in the Brazilian population was estimated. 相似文献
875.
Kankaanpää A Meririnne E Ellermaa S Ariniemi K Seppälä T 《Forensic science international》2001,121(1-2):57-64
The 4-methylaminorex (4-MAX) is an amphetamine-related psychostimulant drug that has appeared on the clandestine market with a street name of "U4Euh". This compound exists as four stereoisomers, trans-4R,5R, trans-4S,5S, cis-4R,5S and cis-4S,5R, of which the cis forms have been classified as Schedule I substances in the US. The increasing variety of designer drugs has highlighted the importance of detection, identification, and quantitative measurement of these drugs, including 4-MAX, in biological samples. In the present study, the isomers of 4-MAX were detected in urine of rats treated with the drugs by some but not all of the on-site immunoassays tested, mainly as amphetamine or methamphetamine. To facilitate identification of 4-MAX by laboratories specialized in drug analysis, the electron-ionization mass spectrum and TLC data for underivatized 4-MAX using a routine laboratory drug-screening procedure is provided. In addition, a GC/MS method is described for the quantitative determination of cis- and trans-4-MAX as tert-butyldimethylsilyl-derivatives in plasma, urine and tissue. 相似文献
876.
Karen Seashore Louis Lisa M. Jones Melissa S. Anderson David Blumenthal Eric G. Campbell 《The Journal of Technology Transfer》2001,26(3):233-245
This paper addresses research in the life sciences, responsible for significant national expenditures for scientific investigations funded by both the federal government and industry. Our investigation examines faculty members' involvement with industry in entrepreneurial ways that is, involved in translating their research into potentially marketable knowledge or products. First, this study examines whether there are differences in entrepreneurial behaviour between clinical and non-clinical faculty in the life sciences with industry relationships, and, second, to discover any linkage between entrepreneurship and secrecy or productivity in different ways for clinical and non-clinical faculty. The study is based on survey responses of a national sample of 4,000 clinical and non-clinical life sciences faculty in 49 U.S. research universities. The results show non-clinical faculty as more involved at the back end. The more entrepreneurial end of commercialization while clinical faculty are involved at the back end. The more entrepreneurial faculty (non-clinical) are more likely to be secretive about their research. Clinical faculty are less likely to have been denied access to research results or products. Entrepreneurial faculty are not less productive in their faculty roles. This investigation is preliminary in that it addresses one large area of academic research but excludes fields with longer historical relationships with industry. 相似文献
877.
878.
879.
880.
Wilschke S 《Social security bulletin》2001,64(1):16-26
Less than half of all children who receive Supplemental Security Income (SSI) benefits and live in a single-parent home receive child support services. Although filing for child support is a condition of eligibility for income assistance programs such as Temporary Assistance for Needy Families (TANF), it is not a condition of eligibility for SSI benefits. Requiring single custodial parents applying for SSI on behalf of their children to pursue child support payments might result in more children on SSI receiving child support, and since the Social Security Administration (SSA) excludes one-third of child support when determining benefit amounts, increased receipt of child support would enhance the financial well-being of SSI children. Improving access to data on child support would enhance the integrity of the SSI program by reducing overpayments to children receiving child support. This article looks at the child support provisions in SSI and other means-tested programs and discusses policy options for improving receipt of child support and access to related data. Requiring cooperation with child support enforcement agencies would be consistent with the philosophy that the SSI program should serve as a program of last resort. Whenever possible, both parents should take primary responsibility for their children. While such a requirement has the potential to improve the financial status of children receiving SSI, factors such as their low-income status and their involvement with the TANF program raise questions about how much those children will actually benefit from such a requirement. Even if many additional children do not receive child support, the requirement demonstrates SSA's dedication to the stewardship of the SSI program. However, if custodial parents fail to comply with the requirement, children may be worse off as a result of the requirement. SSA should carefully pursue a requirement to induce cooperation while protecting children to the greatest extent possible. Improving access to child support data would enhance the integrity of the SSI program by reducing overpayments to children receiving child support. Given the reality of limited administrative resources as well as the apparent difficulties of gaining access to the needed child support data, SSA must decide which data matches to pursue and which requirements enhance the program enough to justify the additional resources. Although the options discussed in this article may be chosen independently, there are important interactions to consider. For example, although a requirement to pursue support might result in more children receiving child support, SSA would still rely on parents to report that income unless it was able to gain better access to child support data. Implementing the option to require cooperation with child support enforcement (CSE) agencies could improve verification of income from child support if field offices developed better communication with local CSE offices. However, by itself, it would not have as great an effect on overpayments as would having direct access to child support data. In a 1999 report, the General Accounting Office acknowledged that the potential benefit reductions would be offset by the cost for SSA to administer a child support cooperation requirement and by the costs to the CSE programs to provide services. The report suggested that the goals of promoting parental responsibility and increasing the income of children receiving SSI should be pursued despite the costs. Requiring cooperation may increase administrative costs by $6 million over 5 years and may result in program savings. Gaining access to data may be more expensive and may not prevent overpayments to the same extent as other data-matching workloads on which SSA has placed a priority. SSA should continue to work with federal child support enforcement and with individual states to develop a cost-effective way to identify child support income. 相似文献