全文获取类型
收费全文 | 12374篇 |
免费 | 391篇 |
专业分类
各国政治 | 558篇 |
工人农民 | 438篇 |
世界政治 | 898篇 |
外交国际关系 | 444篇 |
法律 | 7424篇 |
中国政治 | 89篇 |
政治理论 | 2804篇 |
综合类 | 110篇 |
出版年
2020年 | 135篇 |
2019年 | 213篇 |
2018年 | 244篇 |
2017年 | 286篇 |
2016年 | 304篇 |
2015年 | 217篇 |
2014年 | 252篇 |
2013年 | 1268篇 |
2012年 | 271篇 |
2011年 | 314篇 |
2010年 | 265篇 |
2009年 | 329篇 |
2008年 | 334篇 |
2007年 | 345篇 |
2006年 | 333篇 |
2005年 | 308篇 |
2004年 | 284篇 |
2003年 | 302篇 |
2002年 | 297篇 |
2001年 | 457篇 |
2000年 | 413篇 |
1999年 | 327篇 |
1998年 | 206篇 |
1997年 | 149篇 |
1996年 | 167篇 |
1995年 | 162篇 |
1994年 | 155篇 |
1993年 | 148篇 |
1992年 | 253篇 |
1991年 | 259篇 |
1990年 | 259篇 |
1989年 | 254篇 |
1988年 | 247篇 |
1987年 | 238篇 |
1986年 | 267篇 |
1985年 | 258篇 |
1984年 | 237篇 |
1983年 | 221篇 |
1982年 | 158篇 |
1981年 | 134篇 |
1980年 | 117篇 |
1979年 | 159篇 |
1978年 | 88篇 |
1977年 | 117篇 |
1976年 | 96篇 |
1975年 | 74篇 |
1974年 | 91篇 |
1973年 | 83篇 |
1972年 | 78篇 |
1971年 | 69篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
911.
A method was developed to screen for pepper spray residue using instruments and methods other than those techniques commonly employed to analyze chemical residue (i.e.. gas chromatography mass spectrometry-GCMS or liquid chromatography mass spectrometry-LCMS). The method employed gas chromatography (GC), thin layer chromatography (TLC), and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) to screen for dried pepper spray stains. Pepper sprays from nine different manufacturers were investigated. Capsaicin and dihydrocapsaicin were identified and unique IR reflectance spectra are presented. An additional five compounds were presumptively found. Results showed that a particular stain could be characterized as a pepper-based stain. 相似文献
912.
Perry PJ Kutscher EC Lund BC Yates WR Holman TL Demers L 《Journal of forensic sciences》2003,48(3):646-651
Supraphysiologic doses of testosterone are associated with increased aggression that is hypothesized to be a function of testosterone serum concentrations, mood, and personality. The study attempted to characterize this relationship among weightlifters who were users (n = 10) and nonusers (n = 18) of anabolic steroids. Participants were interviewed using the Modified Mania Rating Scale and Hamilton Rating Scale for Depression to assess mood, the Buss-Durkee Hostility Inventory (BDHI) and Point Subtraction Aggression Paradigm (PSAP) to assess aggression, and the Personality Disorder Questionnaire (PDQ-R) to assess personality. Blood samples were obtained for the determination of total, free, and weakly bound testosterone. Comparisons of continuous variables between testosterone users and non-users were performed with a parametric (unpaired t-test) or non-parametric (Mann-Whitney) test where appropriate. Correlations with testosterone were examined separately for testosterone users and non-users, using Spearman rank correlation. The subjective (BDHI) and objective (PSAP) assessments of aggression found that supranormal testosterone concentrations were associated with increased aggression. However, the PDQ-R results suggest that this finding was confounded by the personality disorder profile of the steroid users, because steroid users demonstrated Cluster B personality disorder traits for antisocial, borderline, and histrionic personality disorder. 相似文献
913.
Baker AM Johnson DG Levisky JA Hearn WL Moore KA Levine B Nelson SJ 《Journal of forensic sciences》2003,48(2):425-428
Diphenhydramine is an antihistamine available in numerous over-the-counter preparations. Often used for its sedative effects in adults, it can cause paradoxical central nervous system stimulation in children, with effects ranging from excitation to seizures and death. Reports of fatal intoxications in young children are rare. We present five cases of fatal intoxication in infants 6, 8, 9, 12, and 12 weeks old. Postmortem blood diphenhydramine levels in the cases were 1.6, 1.5, 1.6, 1.1 and 1.1 mg/L, respectively. Anatomic findings in each case were normal. In one case the child's father admitted giving the infant diphenhydramine in an attempt to induce the infant to sleep; in another case, a daycare provider admitted putting diphenhydramine in a baby bottle. Two cases remain unsolved; one case remains under investigation. The postmortem drug levels in these cases are lower than seen in adult fatalities. We review the literature on diphenhydramine toxicity, particularly as it pertains to small children, and discuss the rationale for treating these cases as fatal intoxications. 相似文献
914.
Gruszecki AC Kloda S Simmons GT Daly TM Hardy RW Robinson CA 《Journal of forensic sciences》2003,48(2):432-434
A 29-year old female with a history of depression was found dead in a hotel room. The death scene investigation found empty pill bottles and an empty liter bottle of wine. Metaxalone, a centrally acting muscle relaxant, along with citalopram, ethanol, and chlorpheniramine were identified in the postmortem samples and quantitated by gas chromatography-mass spectrometry. The concentration of metaxalone in femoral vein blood was 39 mg/L. The heart blood concentration was 54 mg/L. Femoral vein blood concentrations of citalopram and chlorpheniramine were 0.77 mg/L and 0.04 mg/L, respectively. Ethanol levels were 0.13 g/dL in vitreous and 0.08 g/dL in heart blood. Other tissue samples were also analyzed. The authors consider the metaxalone concentrations toxic and potentially fatal. The citalopram concentrations were lower than those reported in fatal cases for this drug alone. Death was ascribed to polydrug abuse/overdose with metaxalone a major contributor. This represents the first reported case to our knowledge in which a metaxalone overdose significantly contributed to death. 相似文献
915.
The presence of cocaine in illicit drug samples is still being determined in some laboratories using spot tests and microcrystal tests. Seventeen chemical species were tested using three different spot tests (Wagner, Marquis, and cobalt thiocyanate followed by stannous chloride reactions) and two microcrystal tests (gold chloride and platinic chloride) to determine whether the results could be differentiated from the results of these tests on cocaine. The data obtained indicated that nine of the 17 compounds gave results similar to those from cocaine using the three spot tests, but that the results from microcrystal testing allowed for differentiation of all nine compounds from cocaine. 相似文献
916.
Introduction
Introduction to special issue on professional insecurities 相似文献917.
Commentary
Commentaries on Brunner and Willards professional insecurities 相似文献918.
919.
920.
Subject Acquisition for Web-Based Surveys 总被引:1,自引:0,他引:1