全文获取类型
收费全文 | 2622篇 |
免费 | 41篇 |
专业分类
各国政治 | 126篇 |
工人农民 | 66篇 |
世界政治 | 152篇 |
外交国际关系 | 68篇 |
法律 | 1924篇 |
中国政治 | 21篇 |
政治理论 | 289篇 |
综合类 | 17篇 |
出版年
2020年 | 30篇 |
2019年 | 22篇 |
2018年 | 22篇 |
2017年 | 33篇 |
2016年 | 40篇 |
2015年 | 23篇 |
2014年 | 38篇 |
2013年 | 193篇 |
2012年 | 60篇 |
2011年 | 68篇 |
2010年 | 36篇 |
2009年 | 37篇 |
2008年 | 56篇 |
2007年 | 71篇 |
2006年 | 72篇 |
2005年 | 75篇 |
2004年 | 73篇 |
2003年 | 72篇 |
2002年 | 70篇 |
2001年 | 156篇 |
2000年 | 123篇 |
1999年 | 76篇 |
1998年 | 26篇 |
1995年 | 18篇 |
1994年 | 22篇 |
1993年 | 21篇 |
1992年 | 63篇 |
1991年 | 70篇 |
1990年 | 61篇 |
1989年 | 84篇 |
1988年 | 83篇 |
1987年 | 72篇 |
1986年 | 76篇 |
1985年 | 65篇 |
1984年 | 35篇 |
1983年 | 41篇 |
1982年 | 19篇 |
1981年 | 30篇 |
1979年 | 28篇 |
1978年 | 21篇 |
1977年 | 27篇 |
1976年 | 19篇 |
1975年 | 31篇 |
1974年 | 30篇 |
1973年 | 31篇 |
1972年 | 32篇 |
1971年 | 24篇 |
1970年 | 20篇 |
1969年 | 24篇 |
1968年 | 20篇 |
排序方式: 共有2663条查询结果,搜索用时 15 毫秒
991.
992.
993.
The genetically determined polymorphism of alpha 2 HS-glycoprotein was analyzed by immunoblotting ultrathin-layer polyacrylamide gel isoelectric focusing in the pH range 4-6.5 and neuraminidase pretreated sera. In a Libyan population sample from Tripoli (n = 110) three common phenotypes, alpha 2 HSG 1-1, 2-1, and 2-2, were observed. The allele frequencies were alpha 2 HSG1 = 0.8364 and alpha 2 HSG2 = 0.1636. The theoretical exclusion rate in cases of disputed paternity is 11.8%. 相似文献
994.
Frederic I. Salop 《政策研究评论》1989,9(2):307-326
With the Comprehensive Anti-apartheid Act of 1986, Congress instituted economic sanctions against South Africa, thereby reversing the historic course of U. S. foreign policy. This political innovation constituted a great victory for minority interests. This article utilizes the agenda-setting literature to examine the relationship between Anti-apartheid movement activity in the United States and adoption of economic sanctions against South Africa. The analysis is based upon an events data set consisting of 1353 events appearing in the New York Times between 1960 and 1986, interviews with activists and legislators, and archived materials. The ar- ticle concludes that although the Anti-apartheid movement was only in- directly involved in moving sanctions legislation to the policy agenda, the movement exerted direct influence in the policy process once the legislation had agenda status. 相似文献
995.
The paper gives the results of tests for influence of luminol solution of different composition on detectability of haptoglobin fractions in the bloodstains of different ages. It was stated that alkaline luminol solutions reduce intensity of fractions and may hamper Hp phenotype determination especially in old stains. 相似文献
996.
997.
998.
Asbestos, a fibrous mineral, has unique physical and chemical properties, including resistance to heat, acids, and other chemicals; flexibility; and great tensile strength. The fibers subdivide into unit fibrils of molecular dimensions, resulting in a vast mineral surface area which has a direct bearing on its unusual features and its numerous applications. Its biological effects, which include fibrogenesis and carcinogenesis, may be related to the cellular reaction, to its large specific surface, or to the size and shape of the fibers. Its oncogenic action may be multiplied by other carcinogens, principally cigarette smoking. There is clinical, pathologic, and epidemiologic evidence that exposure to asbestos, following a long latent period, constitutes an important health hazard. Direct occupational exposure, followed by a long lapsed period after the initial exposure, is associated with pleural plaques and pleural effusion, pulmonary parenchymal fibrosis (asbestosis), pulmonary carcinoma, pleural and peritoneal mesothelioma, and other neoplasms. Indirect exposure may also entail an increased risk of lung disease or mesothelioma or both. Medicolegal investigation of suspected cases includes a lifetime occupational history, clinical history including smoking habits, radiological findings, clinical evidence of asbestosis, and may require detection of asbestos tissue burden. 相似文献
999.
1000.