全文获取类型
收费全文 | 5550篇 |
免费 | 100篇 |
专业分类
各国政治 | 221篇 |
工人农民 | 154篇 |
世界政治 | 296篇 |
外交国际关系 | 156篇 |
法律 | 4098篇 |
中国政治 | 37篇 |
政治理论 | 636篇 |
综合类 | 52篇 |
出版年
2020年 | 61篇 |
2019年 | 56篇 |
2018年 | 76篇 |
2017年 | 75篇 |
2016年 | 103篇 |
2015年 | 51篇 |
2014年 | 88篇 |
2013年 | 425篇 |
2012年 | 128篇 |
2011年 | 178篇 |
2010年 | 110篇 |
2009年 | 95篇 |
2008年 | 152篇 |
2007年 | 168篇 |
2006年 | 158篇 |
2005年 | 139篇 |
2004年 | 168篇 |
2003年 | 162篇 |
2002年 | 142篇 |
2001年 | 278篇 |
2000年 | 236篇 |
1999年 | 159篇 |
1998年 | 45篇 |
1995年 | 34篇 |
1994年 | 38篇 |
1993年 | 48篇 |
1992年 | 113篇 |
1991年 | 139篇 |
1990年 | 131篇 |
1989年 | 160篇 |
1988年 | 165篇 |
1987年 | 148篇 |
1986年 | 139篇 |
1985年 | 129篇 |
1984年 | 97篇 |
1983年 | 93篇 |
1982年 | 42篇 |
1981年 | 49篇 |
1979年 | 55篇 |
1978年 | 48篇 |
1977年 | 45篇 |
1976年 | 40篇 |
1975年 | 55篇 |
1974年 | 60篇 |
1973年 | 63篇 |
1972年 | 61篇 |
1971年 | 52篇 |
1970年 | 52篇 |
1969年 | 48篇 |
1968年 | 42篇 |
排序方式: 共有5650条查询结果,搜索用时 15 毫秒
971.
972.
Thogmartin JR Wilson CI Palma NA Ignacio SS Shuman MJ Flannagan LM 《Journal of forensic sciences》2011,56(5):1352-1360
This study presents a series of 16 carriers of hemoglobin S (HbS) who died during various circumstances. Many of the cases were associated with mild to moderate exertion. The onset and/or duration of symptoms varied from a few minutes to several hours with many displaying a prolonged lucid interval with stable vital signs. Despite seeking medical treatment, sickle cell trait-related micro-occlusive crisis was never considered in the differential diagnosis. Several cases were associated with sudden death. In those deaths which were delayed, high anion gap and uncompensated metabolic acidosis were typical and were not heat related. Also characteristic were large increases in creatine kinase, alanine aminotransferase, and aspartate aminotransferase along with myoglobinemia. Although the antemortem diagnosis of rhabdomyolysis was made, the underlying cause was never deduced by the clinicians. The sickling found at autopsy is not always a postmortem artifact, and in the right circumstances can be diagnostic. 相似文献
973.
Benjamin J. Routon B.S. Brandon B. Kocher B.S. John V. Goodpaster Ph.D. 《Journal of forensic sciences》2011,56(1):194-199
Abstract: Pyrodex ® and Triple Seven ® are black powder substitutes that often find use as fillers in improvised explosive devices, such as pipe bombs. These propellants have essentially the same overall appearance and oxidizers, but different fuels. For example, Pyrodex ® contains sulfur, sodium benzoate, and dicyandiamide (DCDA), whereas Triple Seven ® lacks sulfur but also contains 3‐nitrobenzoic acid. In this method, intact particles and postblast solid residues were reacted with bis(trimethylsilyl)trifluoroacetamide + 1% trimethylchlorosilane in acetonitrile for 30 min at 60°C. The resultant trimethylsilyl derivatives of the organic fuels were then analyzed by gas chromatography–mass spectrometry. Each derivative was clearly resolved from other components, and high‐quality mass spectra were obtained. In addition, characteristic fragments resulting from loss of a methyl radical from the molecular ion (m/z 163 for sulfur, m/z 171 for DCDA, m/z 179 for benzoic acid, and m/z 224 for nitrobenzoic acid) were able to be monitored. 相似文献
974.
Droblenkov AV 《Sudebno-meditsinskaia ekspertiza》2011,54(5):11-17
Forensic medical diagnostics of ethanol poisoning, alcohol abstinence, and chronic alcoholic intoxication of the mesocorticolimbic dopaminergic system remains an unresolved problem and encounters difficulties. This situation is due not only to the marked vulnerability of the neurons of the dopaminergic system but also to the fact that its mechanisms are poorly understood. The objective of the present work was to substantiate and develop diagnostic criteria for ethanol poisoning, alcohol abstinence, and chronic alcoholic intoxication of the neurons both in the mesocorticolimbic dopaminergic system and in other brain regions. The object of the study was the brain of healthy adult subjects who died from alcohol intoxication (in the period of ethanol resorption) and under conditions of alcohol abstinence (completion of the abstinence course). The purpose of the study was to elucidate factors responsible for the different degree of damage to the neurons of various identification groups (intact, hypochromic, picnomorphic, shadow) and macrogliocytes. The cells of all these types were counted at an area of 0.25 sq. mm within 4 squares each having a side of 250 mcm in length. The absolute and relative number of neurons in each group as well as the number of polyneuronal satellite cells per one intact neuron was determined. It was shown that alcohol intoxication is associated with acute swelling of and severe damage to brain neurons caused by the combination of such factors as toxic effect of ethanol, excessive production of catecholamines, and functional overstrain of dopaminergic neurons. The severity of acute alcohol damage to the neurons decreased with the distance from the mid-brain dopaminergic nuclei. Restoration of neurons during alcohol abstinence was due to compensatory activation of interactions between neurons and glial cells. It decreased in the sequence from the paranigral nucleus of the ventral portion of mesencephalic tegumentum to the medial portion of the accumbence nucleus (field 24b, layer III of field la, layer V of field 1) depending on the initial severity of acute damage in the brain region being examined. The severity of damage to the neurons of the mesocorticolimbic dopaminergic system under conditions of chronic alcohol intoxication estimated from the number of shadow neurons was similar to the degree of acute swelling associated with ethanol poisoning and decreases from a maximum in the nuclei of the mesocorticolimbic dopaminergic system to a minimum in layer III of field 1. 相似文献
975.
976.
The authors present the results of an experimental study designed to estimate the damage to biological and non-biological objects inflicted by the knife blades having the gear-type sharpening. It was shown that a knife with such sharpening leaves edges of the damage of characteristic shape and outline. The results of the study testify to the expediency of further studies on the damaging action of knives considered in the present paper. 相似文献
977.
The results of extraction of lambda-cigalotrin from dioxan aqueous solutions by hydrophobic organic solvents are presented. It is shown that the degree of extraction depends on the nature of the extractant, the water to dioxan ratio, and saturation of the water-dioxan layer with the electrolyte. The highest efficiency of lambda-cigalotrin extraction was achieved using chlorophorm as a solvent under desalination conditions. The extraction factor was calculated necessary to obtain the desired amount of lambda-cigalotrin from the water-dioxan solution (4:1) with the help of the extractants being used. 相似文献
978.
Procedures of forensic medical examination are considered with special reference to the cases of unfavourable outcomes of the treatment and methodological basis of their expert assessment. The step-by-step analysis of the doctor's actions is proposed for their objective evaluation. The objective opinion of the expert commission should be based on the medical criteria for the doctor's actions. 相似文献
979.
Based on the results of the present experimental study, morphological and histological criteria for incised skin wounds from objects differing in the blade sharpness were developed. 相似文献
980.
Dynamics of postmortem autolysis of cardiocytes was evaluated using cells and tissues obtained from the patients who died from acute forms of ischemic heart disease, such as acute coronary insufficiency and acute myocardial infarction in the pre-necrotic phase. The studies were carried out at a temperature of 7, 20, and 37 degrees C. It was shown that autolysis of cardiac muscular fibers proceeds through three successive stages. A rise in temperature from 7 to 20 degrees C accelerated autolysis by one third while further elevation of the temperature up to 37 degrees C was associated with a 9-fold decrease in the duration of autolysis. 相似文献