全文获取类型
收费全文 | 25037篇 |
免费 | 1355篇 |
专业分类
各国政治 | 1293篇 |
工人农民 | 1026篇 |
世界政治 | 1925篇 |
外交国际关系 | 1044篇 |
法律 | 15236篇 |
中国共产党 | 2篇 |
中国政治 | 174篇 |
政治理论 | 5480篇 |
综合类 | 212篇 |
出版年
2023年 | 118篇 |
2021年 | 131篇 |
2020年 | 519篇 |
2019年 | 587篇 |
2018年 | 749篇 |
2017年 | 778篇 |
2016年 | 869篇 |
2015年 | 656篇 |
2014年 | 751篇 |
2013年 | 3014篇 |
2012年 | 700篇 |
2011年 | 721篇 |
2010年 | 710篇 |
2009年 | 749篇 |
2008年 | 747篇 |
2007年 | 814篇 |
2006年 | 765篇 |
2005年 | 651篇 |
2004年 | 685篇 |
2003年 | 588篇 |
2002年 | 638篇 |
2001年 | 817篇 |
2000年 | 756篇 |
1999年 | 604篇 |
1998年 | 386篇 |
1997年 | 292篇 |
1996年 | 328篇 |
1995年 | 295篇 |
1994年 | 280篇 |
1993年 | 289篇 |
1992年 | 403篇 |
1991年 | 421篇 |
1990年 | 387篇 |
1989年 | 370篇 |
1988年 | 389篇 |
1987年 | 363篇 |
1986年 | 420篇 |
1985年 | 391篇 |
1984年 | 341篇 |
1983年 | 313篇 |
1982年 | 268篇 |
1981年 | 225篇 |
1980年 | 204篇 |
1979年 | 271篇 |
1978年 | 171篇 |
1977年 | 146篇 |
1976年 | 106篇 |
1975年 | 132篇 |
1974年 | 155篇 |
1973年 | 126篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
In the statistical interpretation of forensic glass evidence it is standard practice to make the assumption of homogeneity of the refractive index (RI) of the source glass, or of localized homogeneity. However, the work of Locke and Hayes showed that, for toughened windscreen glass, this assumption might not be true. This work is well cited, but there appears to have been little follow-on published research. Furthermore, the toughening process is something known to affect the refractive index, and is a process that float glass does not undergo. Float glass is a major component of casework in New Zealand and for that reason it would be interesting to know whether the findings of Locke and Hayes apply when dealing with float glass. In this paper we describe an experiment similar to that of Locke and Hayes, systematically examining the variation of RI in a pane of float window glass. It was found that, although there were no systematic differences in refractive index, there were observable differences across the pane. 相似文献
92.
Report of an unusual finding of bones on the shore of the Baltic Sea. Although the morphological findings appeared similar to a human foot skeleton, a quick identification as sea dog bone was possible. 相似文献
93.
In many countries it is left to the discretion of the court to accept or reject conclusions based on sampling procedures as applied to the total drug exhibit. As an alternative to this subjective approach, a statistical basis is presented using binomial and hypergeometric distributions to determine a lower limit for the proportion of units in a population which contains a drug, at a given confidence level. A method for calculating the total weight of a drug present in a population within a given confidence interval is also presented. In the event of no failures (all units sampled contain a drug), a sample size of six or seven units is generally sufficient to state that a proportion of at least 0.70 of the population contains a drug at a confidence level of at least 90%. When failures do occur in the sample, point estimation is used as the basis for selecting the appropriate sample size. 相似文献
94.
Y Aoki H Terunuma Y Iwasaki M Nata K Sagisaka 《The American journal of forensic medicine and pathology》1992,13(3):199-203
A case of the sudden death of a 14-month-old girl due to massive hemorrhage in a primitive neuroectodermal tumor (PNET) is presented along with a review of the relevant literature. PNET is a rare, malignant brain neoplasm occurring predominantly in children. 相似文献
95.
96.
An improved method has been developed for the reliable classification of different C1R genetic variant forms from human serum or plasma. The method combines the use of neuraminidase-digested samples followed by monodimensional isoelectric focusing in the pH range 5 to 8 followed by immunoblotting. The method yields a simple pattern, with one major band in homozygote and two major bands in heterozygote cases. 相似文献
97.
98.
Dilutions of 100 serum samples of various GM phenotypes were dotted onto a nitrocellulose membrane. The serum dot-blots were detected with peroxidase-labeled anti-G3M T monoclonal antibody (anti-G3M T MAb). Up to a 1 : 256 dilution could be G3M T-typed correctly. By use of anti-G3M T MAb and peroxidase-labeled anti-mouse IgG or the biotin-avidin system instead of use of labeled anti-G3M T MAb, up to a 1 : 512 or 1 : 1024, respectively, dilution was typable. As with previous work with G3M G MAb, the dot immunobinding (DIB) method for G3M T typing was found very simple and practical. 相似文献
99.
M Moniri 《Journal of forensic sciences》1990,35(1):181-185
A technique was developed for Gm/Km typing of bloodstains and sera in U-bottom microtiter plates. Gm/Km typing of sweat and urine samples was also attempted with limited success. 相似文献
100.