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   6199篇
  免费   696篇
  国内免费   21篇
耳鼻咽喉   32篇
儿科学   204篇
妇产科学   123篇
基础医学   933篇
口腔科学   263篇
临床医学   657篇
内科学   1681篇
皮肤病学   169篇
神经病学   400篇
特种医学   366篇
外科学   726篇
综合类   156篇
一般理论   4篇
预防医学   422篇
眼科学   155篇
药学   363篇
中国医学   2篇
肿瘤学   260篇
  2021年   85篇
  2020年   60篇
  2019年   68篇
  2018年   88篇
  2017年   70篇
  2016年   85篇
  2015年   99篇
  2014年   128篇
  2013年   196篇
  2012年   221篇
  2011年   271篇
  2010年   177篇
  2009年   163篇
  2008年   235篇
  2007年   253篇
  2006年   288篇
  2005年   245篇
  2004年   228篇
  2003年   200篇
  2002年   223篇
  2001年   229篇
  2000年   246篇
  1999年   194篇
  1998年   135篇
  1997年   87篇
  1996年   112篇
  1995年   72篇
  1994年   76篇
  1993年   69篇
  1992年   185篇
  1991年   145篇
  1990年   143篇
  1989年   133篇
  1988年   144篇
  1987年   131篇
  1986年   124篇
  1985年   139篇
  1984年   95篇
  1983年   95篇
  1982年   69篇
  1981年   67篇
  1979年   93篇
  1978年   63篇
  1977年   51篇
  1976年   62篇
  1975年   46篇
  1974年   48篇
  1972年   59篇
  1971年   56篇
  1970年   56篇
排序方式: 共有6916条查询结果,搜索用时 31 毫秒
31.
A multivariate analysis of the relationship between biochemical measures of hepatic function and neuropsychological assessments of specific cognitive domains was performed on data obtained from 74 patients with chronic liver disease and subclinical hepatic encephalopathy. Biochemical tests of hepatic protein synthesis correlated significantly with measures of impaired language efficiency, perceptual speed, and psychomotor efficiency. Biochemical indices of impaired processing of nitrogenous compounds correlated with visuopractic deficits. Hepatic blood flow indices correlated with language inefficiency. Interestingly, biochemical measures of hepatic injury did not demonstrate a significant association with any neuropsychological parameter assessed. These results suggest that subclinical hepatic encephalopathy is the consequence of a multifactorial hepatic dysfunction, and that acute hepatic injury, as assessed by elevation of aminotransferases, does not appear to be involved in the pathogenesis of subclinical hepatic encephalopathy.  相似文献   
32.
Hyperglycemia is an important risk factor for the development of retinopathy and nephropathy in people with diabetes mellitus. There are few population-based data on changes in glycemia over time. The purpose of this study was to examine changes in glycemia, as measured by glycosylated hemoglobin in 1980 to 1982 and in 1984 to 1986, in a large population-based study of people who were diagnosed to have diabetes before the age of 30 years and who used insulin (n = 697). Glycosylated hemoglobin was measured by a microcolumn technique at both examinations. There was a significant (P < .001) fall in the mean glycosylated hemoglobin from 10.8 to 10.1% over the 4-year interval of the study. In contrast, there was no change in the glycosylated hemoglobin (6.2%) in a similarly aged nondiabetic comparison group over the same period. The decrease in mean glycosylated hemoglobin over the 4-year period in the diabetic group was associated with several characteristics of diabetes management. These include changes in the insulin regimen (going from intermediate- or long-acting insulin only to combinations with short-acting insulin), an increase in the number of doses of insulin per day, and a higher frequency of self-monitoring of blood glucose level. It was also associated with an increased number of reported insulin reactions. These data suggest that recent changes in treatment and management of diabetes may be related to a significant decrease in glycemia.  相似文献   
33.
Aspergillus osteomyelitis is a rare condition and is a recognized infection of the immunosuppressed. The pediatric cases that were documented suggest that in children, chronic granulomatous disease is the major underlying disease [Tack et al.1982 73(2):295–300, Baez-Escudero et al. 2000 Case report—primary sternal Aspergillus osteomyelitis. Infect Med 17(7):505–516]. We report an interesting case of Aspergillus osteomyelitis of the thumb in a 5-year-old boy with aplastic anemia. The infection progressed despite a combination of antifungal therapy with Voriconazole and surgical debridement. The thumb was amputated and the child recovered. This case highlights the difficulty in diagnosing Aspergillus osteomyelitis and also the failure of conventional management in this child, which resulted in the amputation of the thumb as a life-saving measure. We believe this to be the first case report of Aspergillus osteomyelitis in the thumb.  相似文献   
34.
35.
The fourth edition of this book is equally as good as its predecessorsand fulfils the aims of the authors, as stated in the preface,to provide a concise and easily accessible compendium of neuroanaesthesiaand neurosurgical critical care. The chapters have been updatedto reflect new techniques and practices for topics such as awakecraniotomy, diagnostic and interventional neuroradiology, monitoringof patients for neurosurgery and neurocritical care, and managementof head injury and subarachnoid haemorrhage. It is a multi-author  相似文献   
36.
37.
The objective of the study was to test for an association between type 2 diabetes mellitus (T2DM) and body mass index (BMI) and three single nucleotide polymorphisms (SNP)s in the peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1alpha) gene. We were also interested in whether these associations differed by tertiles of diet, physical activity or presence of polymorphisms in the peroxisome proliferator-activated receptor gamma (PPAR-gamma) gene among Hispanics and Non-Hispanic Whites (NHW) from Colorado. We studied 216 Hispanic pedigrees (1850 nuclear families) and 236 NHW pedigrees (1240 families) from the San Luis Valley and Denver. We genotyped the Gly482Ser, Thr528Thr and Thr612Met polymorphisms in the PGC-1alpha gene and the Pro12Ala polymorphism of the PPAR-gamma gene. Historical physical activity (average METS/week) as well as average dietary intake over the past year was assessed by self-report. Data were analyzed using the Family Based Association Test (FBAT) as well as generalized estimating equations (GEE). We did not find any significant association between three SNPs in the PGC-1alpha gene and T2DM in Hispanics or NHW; however, using FBAT, we found the common Thr612Thr allele of the PGC-1alpha gene to be associated with T2DM among Hispanic subjects carrying the rare Pro12Ala allele of the PPAR-gamma gene (p=.003). We found similar associations when we considered a haplotype containing that allele (p=.002). However, the results of the GEE analysis did not confirm these findings: odds ratio (OR)=1.68, 95% CI (0.5, 5.2) suggesting these results may due to chance. BMI also did not show any consistent associations with the PGC-1alpha gene. In conclusion, we did not find an association between the PGC-1alpha gene and T2DM or BMI and there were no consistent interactions with diet, physical activity or the Pro12Ala polymorphism of the PPAR-gamma gene.  相似文献   
38.
The Model for End-Stage Liver Disease (MELD) is used to assign priority for liver transplantation candidates. The Organ Procurement and Transplantation Network (OPTN) approved recognized exceptional diagnoses (RED's) for which MELD fails to accurately measure priority. Centers can request increased MELD points in cases not recognized by this policy (non-RED's). Our aim was to compare regional practices to justify non-RED requests for MELD adjustments. The UNOS/OPTN database was queried to extract all adult cases for which a non-RED MELD adjustment was requested from 2/27/02 until 8/27/03. The data were stratified by region and justification. Data for 29,510 listings were available. 26,947 had complete diagnosis information. There were 827 non-RED requests of which 477 (57.7%) petitions were approved by the regional review boards (RRBs). The approval rate varied significantly among regions (range: 28-75%, p<0.0001). The most common non-RED's were complications of portal hypertension (48%). The percentage of patients listed with non-RED's varied significantly among regions (0.7-8.3 %, p<0.0001), as did the proportion of patients transplanted with non-RED's (2.1-31.9%, p<0.0001). Demographics did not differ among regions requesting non-REDs.Widespread regional variations exist in the handling of requests for non-REDs. These variations point to the need for reform to standard exception criteria.  相似文献   
39.
BACKGROUND: Some studies have associated alcohol dependence (AD) with the human serotonin (5-HT)(1B) receptor (HTR1B). This investigation explored the functional responsivity of HTR1B in abstinent AD men using a sumatriptan challenge, while measuring genetic heterogeneity in the HTR1B promoter. METHODS: Abstinent AD men (n = 27) and abstinent men without any alcohol use disorder (n = 19) were administered 6 mg of sumatriptan succinate, subcutaneously. Plasma samples collected over the following 2 hours were assayed for growth hormone (GH) concentrations. His DNA was genotyped for the A-161T and T-261G polymorphisms of the HTR1B promoter and diplotypes determined. RESULTS: Integrated GH responses were predicted by interactions of AD and promoter diplotypes, as well as subject ethnicity. The final model accounted for nearly 35% of the variance in GH responses. Post hoc evaluation revealed that AD was associated with a blunting of GH secretion only among individuals with the most common HTR1B diplotype (TT/TT). CONCLUSIONS: A blunting of GH responses in abstinent AD men was observed only among those with the most common HTR1B promoter diplotype. Less common promoter diplotypes appeared protective. Controlling for genetic background is a useful augmentation of case-control pharmacological challenge strategies designed to elucidate the psychobiology of AD and other complex disorders.  相似文献   
40.
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