全文获取类型
收费全文 | 3444篇 |
免费 | 56篇 |
专业分类
各国政治 | 98篇 |
工人农民 | 93篇 |
世界政治 | 146篇 |
外交国际关系 | 95篇 |
法律 | 2653篇 |
中国政治 | 18篇 |
政治理论 | 357篇 |
综合类 | 40篇 |
出版年
2020年 | 34篇 |
2019年 | 34篇 |
2018年 | 54篇 |
2017年 | 43篇 |
2016年 | 64篇 |
2015年 | 29篇 |
2014年 | 53篇 |
2013年 | 246篇 |
2012年 | 87篇 |
2011年 | 132篇 |
2010年 | 79篇 |
2009年 | 63篇 |
2008年 | 108篇 |
2007年 | 121篇 |
2006年 | 106篇 |
2005年 | 85篇 |
2004年 | 121篇 |
2003年 | 113篇 |
2002年 | 109篇 |
2001年 | 150篇 |
2000年 | 134篇 |
1999年 | 103篇 |
1998年 | 20篇 |
1995年 | 17篇 |
1993年 | 27篇 |
1992年 | 62篇 |
1991年 | 84篇 |
1990年 | 86篇 |
1989年 | 91篇 |
1988年 | 95篇 |
1987年 | 89篇 |
1986年 | 75篇 |
1985年 | 77篇 |
1984年 | 67篇 |
1983年 | 58篇 |
1982年 | 24篇 |
1981年 | 20篇 |
1979年 | 30篇 |
1978年 | 33篇 |
1977年 | 22篇 |
1976年 | 27篇 |
1975年 | 28篇 |
1974年 | 37篇 |
1973年 | 37篇 |
1972年 | 35篇 |
1971年 | 36篇 |
1970年 | 38篇 |
1969年 | 32篇 |
1968年 | 27篇 |
1967年 | 18篇 |
排序方式: 共有3500条查询结果,搜索用时 10 毫秒
211.
Benner BA Goodpaster JV DeGrasse JA Tully LA Levin BC 《Journal of forensic sciences》2003,48(3):554-563
This paper discusses results of a supercritical fluid extraction-gas chromatography/mass spectrometry (SFE-GC/MS) study of small samples ( 100 microg to 1 mg) of human scalp hair. The method offers a number of benefits including greater sensitivity than liquid extraction methods because the entire extractable mass is transferred to the analytical system, compared with only a few percent from a conventional liquid extraction/injection. The project's goals were to determine if SFE-GC/MS analyses of the surface-extractable components of an individual's hair yield consistent chemical profiles and to investigate if the profiles are sufficiently different to distinguish them from those of other individuals. In addition, the mtDNA sequences from ten of the same individuals used in the SFE-GC/MS study from four family units were determined, and, while the families were distinguishable, the maternal relations yielded identical sequences. In tandem, SFE-GC/MS and mtDNA techniques may provide valuable complementary data from forensic hair samples. 相似文献
212.
Elizarova MK Udalov VS Karamyshev NN Shormanov VK 《Sudebno-meditsinskaia ekspertiza》2003,46(4):32-35
The results of extraction of 1,2- and 1,4-dihydroxybenzene from water solutions by the hydrophobic and hydrophilic organic solvents are described. The influence of an extragent nature and of a water-phase pH medium on an extraction degree is demonstrated. The repetition factor needed to extract a preset quantity of examined compounds is calculated. 相似文献
213.
214.
With due regard for the economic situation in regions, differences in the material-technical and personnel provision of each forensic-medical bureau (FMB), paying capacity of local residents and for other factors, a method for estimating the cost of forensic medical services was elaborated and offered for use. The formula of cost estimation for rendered services allow for basic wages (BW) and bonuses, sick-list and vacation payments, overhead charges (including FMB wear-and-tear), and BW assignment to off-budget funds (which constitute, in total, the self-cost of services) as well as the planned profit and road taxes. 相似文献
215.
A total of 743 lethal outcomes of thromboembolytic complications of trauma, diseases and certain pathological conditions as observed in 1999-2001 and in the three quarters of 2002 were studied. The undertaken analysis confirmed two factors provoking the pathological thrombosis, i.e. 1. Pathological changes observed in the surface vascular wall preconditioned by mechanical damages, atherosclerotic process and aging; and 2. A slower blood flow due to an impaired blood circulation, a forced positioning and to hypodynamics. While deciding on a possibility of a direct cause-effect relation between past traumas, surgeries, poisonings and death of thromboembolism of the pulmonary arteries (TEPA), such relation can be mentioned only on rare occasions. It is more often the case that an indirect, mediated relationship is found, when TERA evolves due to an unfavorable combination of risk factors, i.e. a forced immobility, changing coagulated blood system, impaired blood vessels etc. 相似文献
216.
The case study was based on the osteologic collection of the chair for anthropology, State Moscow University, including the male carpal bones (67) and female carpal bones (13), aged above 18 to 20. Four measurements were made according to Martin's scheme for metacarpal bones and finger phalanxes. A diagnostic method was worked out on the bases of the discriminative analysis, with such method enabling the remodeling of the ordinal localization of metacarpal bones as well as of main, medium and distal phalanxes. The maximally accurate classification was ensured for metacarpal bones, ranging from 81.5% to 100%; and the minimally accurate one was achieved for distal phalanxes, ranging from 20% to 95%. The discriminative analysis results were checked for distal phalanxes by Neklyudov's series (male--100, female--85); they were described according to 7 sizes. However, an attempt to enhance the accuracy of the classification of these phalanxes failed. The offered method should be applied in combination with the traditional anatomic-and-morphological method; besides, if possible, it is necessary to check the congruence of joint surfaces in the metacarpal interphalangeal joints. 相似文献
217.
A possibility was studied to use the plaster copies of skulls in the forensic medical identification of personality by applying the craniofacial method. No dependence was found between the plaster casts and the moulding types. Differences between the same craniometric sizes in the skull and in its cast are of an incidental nature. Such incidental deviation is related with an accuracy of determining the localization of craniometric points and with an instrumental precision of measuring devices. The necessity is substantiated that, while making a craniofacial examination, it is necessary to mark all anthropometric points in the skull cast, with the original being a control. The use of a plaster skull cast is possible in those cases, when the burial of the remains must be done in full. 相似文献
218.
Eighteen cadavers of persons, who died of acute and chronic alcohol and drug intoxication (ephedron-addiction), were used to study the changes in the spinal nerve plexuses and external genitals. The activity of acetylcholinesterase and of NADPH-diaphorase was determined histochemically; the adrenergic nerve fibers were detected by a glyoxyl-acid technique. Rectified changes in the relative density of adrenal-cholinergic- and nitroxydergic structures and in the activity of mediators in different intoxications were found. The chronic intoxication by alcohol and ephedron was accompanied by a reduced activity of enzymes involved in the metabolism of acetylcholine, nitric oxide and catecholamines. A lower density was observed in the nerve fibers that contained the examined substances. The results can be used as an additional criterion in evaluating the male sexual-function status. 相似文献
219.
220.
Determination of 2.4-dinitrophenol,its basic metabolite and 4-oxide diphenyl in biological materials
A possibility was considered to isolate, by using dimethylformamide, 2.4-dinitrophenol, 2-amino-4-nitrophenol and 4-oxid-diphenyl from a biological-origin object. A method of extraction with subsequent chromatography in thin silicon-gel layer was used to purify the isolates from biological materials. The designed technique provides for identifying and for quantitatively defining the discussed phenol structures contained in the isolates from the liver tissue of corpses and human blood. 相似文献