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   12517篇
  免费   866篇
  国内免费   23篇
耳鼻咽喉   87篇
儿科学   404篇
妇产科学   364篇
基础医学   1540篇
口腔科学   138篇
临床医学   2217篇
内科学   1974篇
皮肤病学   164篇
神经病学   1206篇
特种医学   289篇
外科学   1193篇
综合类   225篇
一般理论   24篇
预防医学   1495篇
眼科学   283篇
药学   821篇
  2篇
中国医学   7篇
肿瘤学   973篇
  2023年   56篇
  2022年   127篇
  2021年   218篇
  2020年   140篇
  2019年   227篇
  2018年   258篇
  2017年   205篇
  2016年   203篇
  2015年   233篇
  2014年   319篇
  2013年   575篇
  2012年   781篇
  2011年   891篇
  2010年   467篇
  2009年   451篇
  2008年   803篇
  2007年   810篇
  2006年   876篇
  2005年   854篇
  2004年   904篇
  2003年   843篇
  2002年   754篇
  2001年   165篇
  2000年   110篇
  1999年   141篇
  1998年   156篇
  1997年   131篇
  1996年   97篇
  1995年   103篇
  1994年   75篇
  1993年   79篇
  1992年   101篇
  1991年   74篇
  1990年   80篇
  1989年   66篇
  1988年   61篇
  1987年   64篇
  1986年   80篇
  1985年   63篇
  1984年   68篇
  1983年   67篇
  1982年   54篇
  1981年   63篇
  1980年   69篇
  1979年   39篇
  1978年   43篇
  1977年   36篇
  1975年   35篇
  1974年   30篇
  1973年   36篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
1.
The purpose of this study was to determine whether blood lipid and lipoprotein concentrations varied in 5 men with advanced HIV-1 infection after 12 months of aerobic exercise training. Prior to exercise, the mean baseline cholesterol and high-density lipoprotein cholesterol (HDL-C) serum concentration were each lower, and mean baseline triglyceride concentration was higher compared to a healthy population norm. Consistent exercise training for 12 months failed to significantly (p > .05) alter cholesterol or HDL-C. Triglyceride concentration was significantly (p < .05) elevated above baseline (63 mg/dL) regardless of exercise compliance. The results suggest that long-term exercise training cannot correct lipid profile abnormality, particularly hypertriglyceridemia, common to individuals with advanced HIV-1 infection.  相似文献   
2.
Abstract:  The risks of developing malignant melanoma (MM) include ultraviolet irradiation and genetic factors. To examine the contribution of rare and common variation within known MM genes in sporadic US MM patients, coding regions of known MM susceptibility genes [cyclin-dependent kinase inhibitor 2A ( CDKN2A ), cyclin-dependent kinase 4, melanocortin 1 receptor ( MC1R ) and tyrosinase ( TYR )] were resequenced in 109–135 MM cases. The significance of variants was examined by comparing their frequencies in 390 cancer-free controls. Potential deleterious mutations in CDKN2A were found in two patients and two others had variants of unknown significance. Cases were more likely than controls to harbour the MC1R 'R' variants known or predicted to alter its function ( P  = 0.002), particularly the R160W variant ( P  = 0.0035). The associated TYR R402Q variant (rs1126809*A) was found in 29% of cases, similar to what has been described previously. One MM patient with a family history of MM, who had developed other skin cancers, was homozygous for a novel TYR variant (P406L) of unknown significance. Hence, rare variants in TYR may be important risk factors for skin cancer.  相似文献   
3.
4.
A peculiarly effective intervention by the author's psychoanalyst is explored and discussed in terms of its implicitly expressive properties. It is placed in the context of the classical concept of opacity and more flexible Sullivanian ideas, as expanded and clarified by Havens.  相似文献   
5.
6.
7.
8.
A primary route of inactivation of leukotrienes and their receptor antagonists (LTRA) is metabolism by omega oxidation. SK&F 102922 [5-(2-(8-phenyloctyl)phenyl)-4,6-dithianonanedioic acid] is a LTRA that was designed to be resistant to omega oxidation. Therefore, these experiments were designed to characterize the metabolic fate of [14C]SK&F 102922. Following iv administration of SK&F 102922 (5 mg/kg), 80% of injected radioactivity was excreted in bile in 1 hr. At least five metabolites and parent (18% of administered dose) were present in bile. One metabolite (M1), which accounted for less than 10% of the excreted radioactivity, was monohydroxylated. Three metabolites (M2, M3A, and M3B), which together accounted for greater than 50% of excreted radioactivity, had mass spectra consistent with acyl glucuronides. All three metabolites were alkali labile, whereas only one metabolite (M2) was susceptible to beta-glucuronidase hydrolysis. These data indicate that M3a and M3b are nonglycosidic isomers of M2 that were formed by a nonenzymic reaction involving migration of the aglycone (SK&F 102922) from C-1 to C-2, C-3, or C-4 of glucuronic acid. The 1-O-acyl-beta-glucuronide of SK&F 102922 (M2) exhibits pH dependent rearrangement, with half-lives ranging from 1 to greater than 1000 hr. Therefore, acyl glucuronidation can account for much of the metabolic fate of SK&F 102922 and, potentially, other structurally related LTRAs or endogenous leukotrienes themselves.  相似文献   
9.
To assess the magnitude and nature of interpersonal violence resulting in hospitalisation of children and to identify subgroups at risk of repeat hospital admissions, a population-based, retrospective study of all violence hospitalisations in Western Australia for children aged 9 years or less was undertaken, using the 1990–2004 linked data retrieved from the Western Australian Mortality Database and the Hospital Morbidity Data System.
Of the 747 patients aged <10 years incurring 834 hospitalisations for the consequences of violence during the study period, 570 (76%) were less than 4 years of age. A total of 43 deaths from violence were recorded and 74 (9%) patients were admitted for more than one episode of violence. Victims aged 0–4 years from rural (hazard ratio [HR] = 2.72; 95% confidence interval [CI] 1.35, 5.43) and remote parts (HR = 2.79; 95% CI 1.25, 6.25) of the state were at increased risk of a subsequent admission for violence compared with those residing within the metropolitan area. Indigenous children aged 5–9 years were significantly more likely (HR = 3.57; 95% CI 1.14, 11.13) to incur a second hospitalisation for violence than their non-Indigenous counterparts. The identification of young victim subgroups at high risk of repeat hospitalisations is important for developing intervention strategies to reduce the burden of interpersonal violence. Young children aged 0–4 years living in rural and remote locations and Indigenous children aged 5–9 years should be specifically targeted for attention.  相似文献   
10.
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