全文获取类型
收费全文 | 16149篇 |
免费 | 795篇 |
专业分类
各国政治 | 828篇 |
工人农民 | 520篇 |
世界政治 | 1403篇 |
外交国际关系 | 727篇 |
法律 | 9404篇 |
中国共产党 | 1篇 |
中国政治 | 99篇 |
政治理论 | 3853篇 |
综合类 | 109篇 |
出版年
2023年 | 74篇 |
2021年 | 111篇 |
2020年 | 283篇 |
2019年 | 366篇 |
2018年 | 386篇 |
2017年 | 465篇 |
2016年 | 482篇 |
2015年 | 351篇 |
2014年 | 428篇 |
2013年 | 1961篇 |
2012年 | 390篇 |
2011年 | 463篇 |
2010年 | 440篇 |
2009年 | 459篇 |
2008年 | 430篇 |
2007年 | 465篇 |
2006年 | 447篇 |
2005年 | 458篇 |
2004年 | 465篇 |
2003年 | 438篇 |
2002年 | 452篇 |
2001年 | 579篇 |
2000年 | 526篇 |
1999年 | 385篇 |
1998年 | 266篇 |
1997年 | 234篇 |
1996年 | 211篇 |
1995年 | 204篇 |
1994年 | 228篇 |
1993年 | 207篇 |
1992年 | 274篇 |
1991年 | 302篇 |
1990年 | 262篇 |
1989年 | 275篇 |
1988年 | 266篇 |
1987年 | 250篇 |
1986年 | 294篇 |
1985年 | 267篇 |
1984年 | 210篇 |
1983年 | 228篇 |
1982年 | 159篇 |
1981年 | 172篇 |
1980年 | 123篇 |
1979年 | 167篇 |
1978年 | 106篇 |
1977年 | 105篇 |
1976年 | 97篇 |
1974年 | 86篇 |
1973年 | 78篇 |
1972年 | 79篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Zhu BL Oritani S Shimotouge K Ishida K Quan L Fujita MQ Ogawa M Maeda H 《Forensic science international》2000,113(1-3):443-447
To outline the recent features of methamphetamine-related fatalities from the medico-legal point of view, a retrospective investigation of forensic autopsy cases involving methamphetamine during a 5-year period (1994-1998) in the southern half of Osaka city and surrounding areas (about 1.57 million population) was undertaken. Among 646 autopsy cases, methamphetamine was detected in 15 victims (nine males, six females; 16-71 years of age; most frequently in males in their thirties). Primary scenes of fatal events were concentrated in the middle of the city. About half of them were transferred from emergency medical centers (survival time, up to 30 h). The cause and manner of death were: methamphetamine poisoning (n=4), homicide (n=4), accidental falls and aspiration from drug abuse (n=4), fire death (n=1), myocardial infarction (n=1), and cerebral hemorrhage (n=1) under drug influence. Usually injection scars and fresh puncture sites were found. Blood methamphetamine concentrations were 2.29-17.05 micromol/dl in the fatal poisoning, 0. 44-3.80 micromol/dl in deaths from other extrinsic causes (trauma), and 1.35-2.17 micromol/dl in cardio- and cerebrovascular strokes. Common complications were cardiomyopathy, cerebral perivasculitis and liver cirrhosis/interstitial hepatitis. Fatal and nonfatal methamphetamine poisonings are separately dealt with by the administrative medical examiner's office and in emergency medical centers. Tightly cooperative approaches of clinical and medico-legal experts are required for the effective social and medical management of drug abuse. 相似文献
992.
DNA typing is often used to determine identity from human remains. The environment to which the material has been exposed, however, is crucial for the success of the investigation. Damp conditions in particular can cause a rapid degradation of DNA, even in bone and teeth, and thus reduce the chances of successful typing. Here, we present the results of investigations performed on four skulls that had been lying in a damp environment for periods ranging from almost 1 year to about 45 years. In none of these cases was DNA typing successful on bone or, where present, on teeth. Where remnants of brain tissue were used, however, complete STR typing was possible in one case, partial STR typing in another, and mtDNA sequencing could be carried out in three cases. These findings suggest that brain tissue is relatively resistant to putrefaction in damp environments and, unlike bone, appears to exhibit a certain degree of protection against DNA degradation. 相似文献
993.
Papillary fibroelastoma is a rare benign tumor, occasionally causing angina or sudden death. We report an autopsy case of an aortic valve papillary fibroelastoma with coronary artery embolism. The patient was a 68-year-old Japanese man who had collapsed suddenly in his house. He was a heavy drinker and had a history of liver disease but no notable cardiac event. The autopsy revealed extensive transmural infarction of the inferior wall of the left and right cardiac ventricles. The distal portion of the right coronary artery (segment 4, NYHA) was completely occluded by tumor emboli of the fibroelastoma. At the site of closure of the aortic non-coronary cusp, there was a typical papillary fibroelastoma, which was considered to have originated the coronary embolization. 相似文献
994.
995.
3,4-methylenedioxyamphetamine (MDA) derivatives are increasingly abused central nervous system stimulants with neurotoxic properties. In recent years a number of controlled substance analogs (designer drugs) with high structural variety reached the illegal market making their identification an arduous task. The underivatized compounds give very similar or even virtually identical electron impact mass spectra containing mainly intense C(n)H(2n+2)N(+) immonium ions. Using tandem mass spectrometry (MS-MS) the additional structural information contained in the collision induced dissoziation (CID) mass spectra of molecular ions using electron impact (EI) and especially chemical ionization (CI) allowed an unequivocal differentiation of 18 studied regioisomeric 1-(methylenedioxyphenyl)-2-propanamines and 1-(methylenedioxyphenyl)-2-butanamines.Further synthetic methods are presented for 1-(3,4-methylenedioxyphenyl)-N-propyl-2-butanamine, N-isopropyl-1-(3,4-methylenedioxyphenyl)-2-butanamine and four 1-(2, 3-methylenedioxyphenyl)-2-butanamines. N-alkylated 1-(3, 4-methylenedioxyphenyl)-2-butanamine compounds (e.g. MBDB) are also known to be abused psychoactive agents (entactogenes) without the sympatomimetic effects of the 3,4-methylenedioxyamphetamines. 相似文献
996.
The binding of charged substances from external aqueous media to hair has been investigated through the use of fluorescence microscopy. Eleven hair samples, reflecting various ethnic groups and cosmetic treatments, were tested. Rhodamine 6G, a cationic dye representative of drugs such as cocaine and opiates, showed incorporation throughout the hair of all samples except one. In contrast, fluorescein, an anionic dye representative of drugs such as THC carboxylic acid, was not readily incorporated. The incorporation of rhodamine 6G was faster for chemically 'straightened' and bleached African-American female hair than for untreated hair. Incorporation of rhodamine 6G followed a pH dependence, but an ionic strength dependence could not be established. These studies support three postulates: (1) electrostatic interactions explain the preferential binding of cationic drugs of abuse to hair; (2) the hair matrix, or the non-helical portion of hair, is accessible to external solutions and thus subject to contamination; and (3) cosmetic treatments may alter the helical portion of hair thereby increasing its accessibility to external contamination. 相似文献
997.
998.
999.
1000.
Ego identity status and decision styles 总被引:1,自引:0,他引:1
It was hypothesized that the decision processes used in coping with the identity crisis would be related to more general decision styles in that identity achievers and moratoriums would tend to be reflective in their conceptual tempo while foreclosures would typically be impulsive. No prediction was made about identity diffusions. Ninety-two male college students were given an identity status interview and the Matching Familiar Figures Test. The results were consistent with the hypotheses, and in addition it was found that identity diffusions were generally impulsive. Since conceptual tempo has been found to be well established in childhood, the results of this study have implications for the early prediction of adult identity status.Received Ph.D. from SUNY/Buffalo. Recent research has been mainly concerned with the development of ego identity and correlates of the different identity statuses.Received Ph.D. from SUNY/Buffalo. Recent research has been mainly concerned with the development of ego identity and correlates of the different identity statuses. 相似文献