首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   16367篇
  免费   522篇
各国政治   818篇
工人农民   547篇
世界政治   1309篇
外交国际关系   718篇
法律   9067篇
中国政治   115篇
政治理论   4160篇
综合类   155篇
  2021年   99篇
  2020年   206篇
  2019年   294篇
  2018年   352篇
  2017年   410篇
  2016年   396篇
  2015年   276篇
  2014年   354篇
  2013年   1938篇
  2012年   375篇
  2011年   419篇
  2010年   371篇
  2009年   430篇
  2008年   415篇
  2007年   481篇
  2006年   434篇
  2005年   454篇
  2004年   455篇
  2003年   443篇
  2002年   446篇
  2001年   539篇
  2000年   477篇
  1999年   389篇
  1998年   245篇
  1997年   207篇
  1996年   219篇
  1995年   223篇
  1994年   222篇
  1993年   205篇
  1992年   311篇
  1991年   333篇
  1990年   296篇
  1989年   310篇
  1988年   286篇
  1987年   285篇
  1986年   326篇
  1985年   316篇
  1984年   280篇
  1983年   272篇
  1982年   192篇
  1981年   179篇
  1980年   152篇
  1979年   188篇
  1978年   117篇
  1977年   141篇
  1976年   121篇
  1975年   86篇
  1974年   104篇
  1973年   95篇
  1972年   92篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
901.
902.
Ketosis occurs in ketoacidosis or malnourishment. When either is suspected in relation to a death, it may be important to analyze for ketosis at autopsy. We encountered a case where starvation was suspected in a deceased nursing home resident, where the body had been embalmed prior to autopsy. Gas chromatography (GC) was unable to separate acetone from formaldehyde, a component of embalming fluid. The Acetest is a simple test that can detect acetone and acetoacetate in body fluids. We validated the Acetest with GC on vitreous. The Acetest and GC were consistent except at very low levels of acetone or acetoacetate. The sensitivity of the Acetest for acetoacetate in vitreous was 10 mg/dL, consistent with early starvation. Significant interference from embalming fluid did not occur. The Acetest was negative in the described case. The Acetest is a simple and useful test for the detection of ketosis in embalmed autopsies.  相似文献   
903.
904.
905.
The article presents the results of an examination of the dry residue of liquor crystallograms (DRLC) using infrared spectroscopy technique. 36 spectrograms were studied. Elements of similarity and difference were revealed in the spectrograms of organic substance (antifreeze, sodium cyclamate and fatty tissue), of DRLC of the crystal-forming matter CuCl(2)x2H(2)0, of DRLC of a live person and cadaveric liquor (with no brain injury in respective case histories), of DRLC of liquor of live persons with a brain injury, of DRLC of liquor of persons who died of a brain injury and of persons who died of other causes.  相似文献   
906.
907.
Bile is, in certain cases, collected together with blood from different sites (heart, brain, femoral), urine and other organs or matrices. This study reports comparative results obtained from the analysis of blood and bile for different drugs found: acetaminophen, amphetamine and related compounds, several antidepressants, several benzodiazepines, cocaine and its metabolites, dextropropoxyphene and its metabolite, hydroxyzine, methadone and metabolite, morphine and codeine, levomepromazine, thioridazine, propranolol, tramadol and its metabolite. Several findings are presented: (1) There were no significant differences in the levels of the compounds among the samples of blood obtained from different sites. (2) Levels in bile are generally several fold higher than those in blood. The mean bile to blood ratios vary from about 1 (for acetaminophen, amphetamine) to about 2000 (for desmethylclobazam). (3) In certain cases (16 over 44), although the drug or its metabolite was not detected in blood from different sites, it was detected in bile. As other authors had advocated, it is very useful to ask the pathologist to take the gall bladder with its contents together with the other samples, in order that the sample of bile can be used in the comprehensive toxicological analysis and therefore be complementary to the other fluids or matrices. An additional advantage for using bile is that the concentrations of drugs or their metabolites are generally several fold higher than their blood concentrations.  相似文献   
908.
Time-of-flight mass spectrometry (TOF-MS) offers new perspectives for forensic toxicology. Qualitative and quantitative analyses of a mixture of three selected benzodiazepines (diazepam, nordazepam and bromazepam) were used to compare gas chromatography (GC-TOF-MS, quadrupole GC-MS, GC-ECD) and liquid chromatography (HPLC-DAD) data. Method validation parameters like LOD, LOQ, S/N-ratios reflect the capabilities of GC-TOF-MS. Five-point calibrations for bromazepam in human peripheral blood (50, 100, 160, 200, 300 ng/ml) using medazepam as internal standard (1000 ng/ml) were performed. The calibrations using GC-TOF-MS (using the fragments of m/z 236 and 288), GC-ECD (dual system) and HPLC-DAD (at 235 nm) all showed correlation coefficients close or superior to 0.99. Quadrupole GC-MS data was not used in the comparison of extracted samples due to the low sensitivity in the full scan mode. Two analyses of real cases concerning bromazepam are presented. In the first case, the presence or absence of bromazepam could not be established with both HPLC-DAD and GC-ECD due to background signals. The extracted ion chromatograms and spectrum traces after the analysis with the GC-TOF-MS could clearly excluded the presence of bromazepam. The second case illustrates the quantitation of bromazepam, where both HPLC-DAD and GC-ECD were unable to give satisfactory results, again due to interfering background signals. The analyses performed on the GC-TOF-MS-system demonstrated high sensitivity and also high selectivity due to the high quality of mass spectra obtained. The advantages of GC-TOF-MS make it a promising analytical technique for forensic toxicology.  相似文献   
909.
Child death due to repeated episodes of physical assault or neglect has been termed the child abuse-maltreatment syndrome (CAMS). We characterized the injuries in a series of fatally abused or maltreated child to delineate objective diagnostic criteria for the CAMS for use by clinicians and pathologists. All deaths (age <17 years) investigated by the Office of the Chief Coroner for Ontario, Canada during the time period 1990-1995 were reviewed. Cases of CAMS were defined as death due to lethal recent injury or malnutrition in the presence of significant old (healing or healed) injuries indicative of repeated episode of inflicted trauma. The nature and frequency of the various injuries was determined. The frequency of the shaken baby syndrome, and the types and frequency of ano-genital injuries were also studied. Twenty-one cases of fatal CAMS were found in the study period. Most cases had significant recent head injury with intra-cranial hemorrhage (71%). Other significant recent injuries commonly observed included blunt injuries of the skin and soft tissues (67%), blunt abdominal trauma with visceral injuries (14%), and fractures (18%). Eight cases (38%) fulfilled accepted criteria for the shaken baby syndrome. Many children with fatal head injuries had evidence of older head trauma (38% of all cases). A significant minority of cases had evidence of malnutrition due to neglect (10%) or ongoing ano-genital injuries (10%). Most cases of child homicides due to repeated episodes of abuse or maltreatment involve head trauma including shaken baby syndrome. Fractures of long bone and ribs, the classical markers of child abuse, were relatively infrequent compared with head injury. A proportion of cases had ano-genital injuries due to repeated sexual abuse or punitive maltreatment. All clinicians and pathologists must recognize the wide spectrum of injuries in child abuse to ultimate protect the victim or other children in an at-risk situation.  相似文献   
910.
The investigation involved the assessment of a model predicting that family and university relationship environments are linked with identity processes and identity states (statuses) that predict psychosocial resources among first-year university students. A sample of 351 university students, between the ages of 18 and 21 years, completed measures of psychosocial maturity based on Erikson's notions of ego virtues, a measure of identity processing styles (diffuse-avoidant, normative, and information styles), identity statuses (diffusion, foreclosure, moratorium, and achievement), measures of family climate (conflict, expression, cohesion), and assessments of university relationships with faculty, advisors, and students. Based on linear structural equations, the model, with some adjustments, had a good fit with the data and demonstrates the complex association between perceived family and school climate, identity formation, and the association with psychosocial resources. The investigation demonstrates how multivariate model testing can be completed to assess some of the complexity suggested by Erik Erikson regarding identity formation. Gerald R Adams is a Professor of Family Relations and Human Development at the University of Guelph in Ontario, Canada. His major interests focus on family relations, identity development, education, and prevention. Michael Berzonsky is Professor of Psychology at State University of New York at Cortland, New York. His major interests are identity styles, social cognition, and adolescent development. Leo Keating is a data analyst at the University of Guelph.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号