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   13266篇
  免费   1281篇
各国政治   558篇
工人农民   455篇
世界政治   962篇
外交国际关系   383篇
法律   9793篇
中国共产党   1篇
中国政治   89篇
政治理论   2225篇
综合类   81篇
  2021年   62篇
  2020年   377篇
  2019年   378篇
  2018年   454篇
  2017年   516篇
  2016年   534篇
  2015年   486篇
  2014年   473篇
  2013年   1444篇
  2012年   381篇
  2011年   454篇
  2010年   588篇
  2009年   540篇
  2008年   342篇
  2007年   333篇
  2006年   397篇
  2005年   282篇
  2004年   271篇
  2003年   256篇
  2002年   239篇
  2001年   466篇
  2000年   378篇
  1999年   315篇
  1998年   156篇
  1997年   139篇
  1996年   117篇
  1995年   142篇
  1994年   147篇
  1993年   121篇
  1992年   225篇
  1991年   242篇
  1990年   228篇
  1989年   240篇
  1988年   209篇
  1987年   180篇
  1986年   214篇
  1985年   230篇
  1984年   227篇
  1983年   195篇
  1982年   156篇
  1981年   133篇
  1980年   134篇
  1979年   155篇
  1978年   100篇
  1977年   81篇
  1976年   69篇
  1975年   76篇
  1974年   81篇
  1973年   67篇
  1971年   59篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Estimation of time of death (TOD) of white-tailed deer is important to wildlife law enforcement officers. The purpose of this study was to develop and test a model for estimating TOD of white-tailed deer in Missouri. We compare the utility of carcass temperature, pupil diameter, and rigor mortis as TOD indicators. The effects of body size, ambient temperature, and various carcass handling methods on the estimate were also examined. Data were collected from 1484 deer during the 1995-96 and 1996-97 hunting seasons. Stepwise regression indicated that all three indicators were significant and that body size and ambient temperature could influence the model. Predictive equations were developed for various combinations of the indicators based on practicality and statistical probabilities. TOD was estimated for 28 animals where the exact TOD was known. There was no significant difference between the estimated and known TOD (p = 0.759) and the average of the absolute differences in 1 h and 28 min.  相似文献   
992.
Allele distributions for 13 tetrameric short tandem repeat (STR) loci, CSF1PO, FGA, TH01, TPOX, VWA, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, and D21S11, were determined in African American, United States Caucasian, Hispanic, Bahamian, Jamaican, and Trinidadian sample populations. There was little evidence for departures from Hardy-Weinberg expectations (HWE) in any of the populations. Based on the exact test, the loci that departed significantly from HWE are: D21S11 (p = 0.010, Bahamians); CSF1PO (p = 0.014, Trinidadians); TPOX (p = 0.011, Jamaicans and p = 0.035, U.S. Caucasians); and D16S539 (p = 0.043, Bahamians). After employing the Bonferroni correction for the number of loci analyzed (i.e., 13 loci per database), these observations are not likely to be significant. There is little evidence for association of alleles between the loci in these databases. The allelic frequency data are similar to other comparable data within the same major population group.  相似文献   
993.
Acetaminophen (paracetamol), a widely used analgetic drug, is well tolerated at therapeutic doses, but may cause severe hepatotoxicity when ingested in large overdose. Self-poisoning is still very popular in adults and accidental ingestion of one single overdose occurs occasionally in children. In contrast, lethal intoxication in children after repeated administration of therapeutic doses is a very rare event. This case report describes an iatrogenic acetaminophen overdosing in a 5-year-old child receiving 8.5 g acetaminophen in 48 h. Fulminant liver failure developed within 60 h. Autopsy findings included panlobular liver cell necrosis. Acetaminophen serum levels were rather low compared to cases with ingestion of one single overdose. Postmortem diagnosis of chronic acetaminophen intoxication as cause of death should include the clinical history as well as, if available, the calculated drug serum half-life.  相似文献   
994.
A validation study was conducted to demonstrate that deoxyribonucleic acid (DNA) could be successfully extracted from human nail material and analyzed using short tandem repeat (STR) profiling and/or mitochondrial DNA (mtDNA) sequencing. This study involved the development of a DNA extraction protocol that includes a cleaning procedure designed to remove external contaminants (e.g., biological, chemical). This protocol was used to test human nail material that had been soaked in whole blood from a second donor and coated with gold-palladium to simulate scanning electron microscopic analysis. The results showed no indication of a mixture and were consistent with that of the nail donor. Fresh human nail material usually yielded both STR profiles and mtDNA sequence information; however, aged human nail material (approximately eight years old) yielded only mtDNA sequence information. Upon completion of the validation study, the extraction protocol was used for the analysis of a torn fingernail fragment recovered from the scene of a violent homicide in 1983. A partial STR profile and mtDNA sequence information indicated that the fingernail fragment was excluded as originating from the suspect and was, in fact, consistent with originating from one of the victims.  相似文献   
995.
Accidental hypothermia has been described in the forensic literature but reports of occurrence in hospitalized patients are rare. Associated anatomic lesions include acute hemorrhagic pancreatitis and characteristic acute gastric ulcers termed Wischnewski ulcers. We report here two patients with cirrhosis and ascites; one also had hepatocellular carcinoma. Portal vein thrombosis, acute hemorrhagic pancreatitis and Wischnewski ulcers were present in both. The clinical records documented hypothermia that progressed over several days. Temperature nadirs of 31.0 degrees C (87.8 degrees F) and 32.2 degrees C (90.0 degrees F) were recorded in each patient, respectively, one day before death, although each transiently reached temperatures that did not register on standard monitoring devices. This is the first report that chronicles antemortem body temperatures in hypothermic patients with Wischnewski ulcers and pancreatitis at autopsy. Also, the association of these findings with portal vein thrombosis and cirrhosis has not been previously described. We discuss this constellation of findings with regard to possible mechanistic interrelations.  相似文献   
996.
Histological analysis of the viscera in experimental poisoning with psilocybin-containing mushrooms showed nonspecific changes in all examined organs, presenting as expressed hemocirculatory disorders and intracellular dystrophy. Quantitative histochemical analysis showed appreciable shifts in the activities of enzymes involved in the cytoplasmic and mitochondrial redox processes and of specific enzymes involved in nerve tissue metabolism. This may reflect some features in the direct effects of narcotic alkaloids contained in psilocybin-producing mushrooms.  相似文献   
997.
Acetylene traces were detected by gas chromatography in the cadaveric right crural muscle of a 30-year-old man dead from an explosion of an acetylene reservoir at a plant. Acetylene was identified using the absolute calibration method on 3 standard gas chromatographic columns, reaction gas chromatography, and acetylene "deduction" by silver sulfate on silicagel.  相似文献   
998.
999.
This study examined the relationship of identity status to ego development and locus of control in 75 college women. The identity statuses did not differ significantly in self-reported locus of control, but did differ on the depth measure of ego development. Consistent with identity theory and with previous research with males, identity achievers and moratorium (incrisis) women were more advanced in their ego development than fore-closure and diffusion women.This article is based in part on the doctoral dissertation of Sheila D. Ginsburg, Submitted in partial fulfillment of the Doctor of Philosophy degree, University of Missouri—St. Louis.Received her Ph.D. in clinical psychology from the University of Missouri—St. Louis. Current research interests include normative and dysfunctional development in children and adolescents.Received his Ph.D. in clinical psychology at State University of New York at Buffalo. Research interests include personality and social development of adolescents and young adults.  相似文献   
1000.
A new 40-item behavioral checklist, the Adolescent Life Assessment Checklist (ALAC), was devised to be used with patient and nonpatient samples. A comparable form obtains information from a parent or guardian. Responses of 356 adolescents from three sources were analyzed for differences attributable to race, sex, age, sample source, and their interactions. A factor analysis was carried out on the average within-race-sex-source subgroup correlation matrix, resulting in seven meaningful and six usable oblique factors. Subscales were developed and corrections were computed to remove estimated differences due to race, sex, and age. Corrected scales significantly differentiate the three samples.This study was supported in part by MCHS Grant No. MC-R-390201, the Adolescent Clinic Foundation, and USPHSMH Fellowship Grant No. 0597921.Received her Ph.D. in psychology from Washington University, St. Louis; received a Foundations Fund for Research in Psychiatry interdisciplinary research-teaching grant, 1959–1965. Current research interests include test development, evaluation, and personality research.Received her M.D. from Medical College of Georgia at Augusta; her medical internship was at Michael Reese Hospital, Chicago, Illinois. Current research interests include stress, coping, and adaptation in children and adolescents.She is a licensed psychologist with the State of Ohio, with an M.A. from the University of Cincinnati. Current research interests include verbal behavior, psychotherapeutic efficacy, and dream research.Received his M.D. from College of Medicine, University of Cincinnati; his medical internship was with Boston City Hospital, and he is the founder of the Adolescent Clinic, Cincinnati General Hospital. Current research interests include growth and development and medical/social problems at adolescence.  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