全文获取类型
收费全文 | 3430篇 |
免费 | 55篇 |
专业分类
各国政治 | 97篇 |
工人农民 | 93篇 |
世界政治 | 145篇 |
外交国际关系 | 95篇 |
法律 | 2650篇 |
中国政治 | 17篇 |
政治理论 | 351篇 |
综合类 | 37篇 |
出版年
2020年 | 33篇 |
2019年 | 34篇 |
2018年 | 54篇 |
2017年 | 42篇 |
2016年 | 63篇 |
2015年 | 28篇 |
2014年 | 51篇 |
2013年 | 245篇 |
2012年 | 86篇 |
2011年 | 132篇 |
2010年 | 79篇 |
2009年 | 61篇 |
2008年 | 108篇 |
2007年 | 121篇 |
2006年 | 106篇 |
2005年 | 84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 | 83篇 |
1990年 | 85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3485条查询结果,搜索用时 0 毫秒
181.
182.
183.
184.
Low explosives such as smokeless powder, black powder, and black powder substitutes have been used in illicit pipe bombings throughout the United States. Some of the newer black powder substitutes are formulated with ascorbic acid, which gradually decomposes as the powder ages, making it difficult if not impossible for the forensic chemist to identify it by traditional bulk techniques. A sensitive method for the identification of residual levels of ascorbic acid in black powder substitutes is presented. Powder samples are extracted with a mixture of acetonitrile and bis(trimethylsilyl)acetamide (BSA), which converts carboxylic acid and alcohol functional groups to trimethylsilyl esters and ethers, respectively. Samples are then analyzed by gas chromatography-mass spectrometry (GC-MS). Results have shown that trace amounts of ascorbic acid can be identified at detection limits that are well below those for traditional bulk techniques. Degradation products for ascorbic acid (hydroxylated carboxylic acids, furanones, and lactones) can also be detected. 相似文献
185.
Kapustin AV 《Sudebno-meditsinskaia ekspertiza》2004,47(5):15-18
The morphological specificity of different conditions of cardiomyocytes was studied in myocardia of 50 cadavers of men who died of a variety of reasons. All conditions, except for the normal relaxation of cardipmyocytes, were found to result from damages in the contractive apparatus. Morphological variations of relaxation of cardiomyocytes are described. 相似文献
186.
The pathomorphology of intoxication of alcohol surrogates is described. A high frequency rate of DIC-syndrome is shown for the condition. A majority of thrombi accumulates at places with the highest concentrations of toxic substances as well as at those places, through which poisoning substances are brought out of the body, i.e. in the liver (since toxic substances are introduced perorally) and kidneys. Thrombi were detected in all internals, including the brain, in lethal intoxication. The immediate toxic effect from methanol and from higher spirits can matter in the genesis of changes, including acute swelling and chromatolysis with subsequent cell death. Exclusively cerebral or coagulopathic-cerebral types of thanatogenesis were registered in studied case of intoxication. 相似文献
187.
Kapustin AV 《Sudebno-meditsinskaia ekspertiza》2004,47(6):22-25
Significance, of the weight and dimensions of heart as well as of fat dystrophy of cardiomyocytes and of the related detection methods is demonstrated for the diagnosis of alcoholic cardiomyopathy (ACMP). When such patients die in a state of alcoholic intoxication, the diagnosis should be death of acute alcoholic intoxication. Lethality of ACMP can be diagnosed only in those who die in the sober condition or with an insignificant level of alcohol. 相似文献
188.
189.
Kornienko IV Vodolazhskiĭ DI Afanas'eva GV Ivanov PL 《Sudebno-meditsinskaia ekspertiza》2004,47(6):27-32
Polymorphism of mDNA D-loop central region (CR), positions 16366-0072) was studied versus hypervariable sections (HVS1), positions 16024-16365, and HVS2, positions 00073-00340, for a sample of 71 residents of the Russian Federation. Ten polymorphic positions with 56 nucleotide substitutions, 55 of which are transitions, were detect in the CR section; no insertions or deletions were found there. It was proven as possible to use the mDNA CR locus as an additional identification marker in the forensic-expert of the mDNA control region. The probability of random coincidence (RC) of haplotypes in joint typing of HVS1, HVS2 and CR made 0.0208, which is 1.4-fold less versus the same parameter for haplotypes HVS1/HVS2 (RC = 0.0284). 相似文献
190.