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   1666922篇
  免费   108742篇
  国内免费   2889篇
耳鼻咽喉   21757篇
儿科学   54512篇
妇产科学   44855篇
基础医学   232826篇
口腔科学   40898篇
临床医学   141872篇
内科学   327067篇
皮肤病学   30207篇
神经病学   136813篇
特种医学   67899篇
外国民族医学   379篇
外科学   260974篇
综合类   31470篇
现状与发展   2篇
一般理论   468篇
预防医学   125677篇
眼科学   36718篇
药学   121653篇
  2篇
中国医学   3410篇
肿瘤学   99094篇
  2021年   12120篇
  2019年   12529篇
  2018年   38965篇
  2017年   30323篇
  2016年   34793篇
  2015年   17619篇
  2014年   24172篇
  2013年   35222篇
  2012年   55444篇
  2011年   72432篇
  2010年   48380篇
  2009年   39805篇
  2008年   69210篇
  2007年   76099篇
  2006年   53467篇
  2005年   54730篇
  2004年   54122篇
  2003年   53402篇
  2002年   50221篇
  2001年   60285篇
  2000年   61591篇
  1999年   52763篇
  1998年   16985篇
  1997年   15119篇
  1996年   14967篇
  1995年   14085篇
  1994年   13347篇
  1993年   12380篇
  1992年   42029篇
  1991年   41360篇
  1990年   40790篇
  1989年   39559篇
  1988年   36863篇
  1987年   36068篇
  1986年   34426篇
  1985年   32893篇
  1984年   24831篇
  1983年   21620篇
  1982年   13414篇
  1979年   23160篇
  1978年   16430篇
  1977年   14172篇
  1976年   13419篇
  1975年   14497篇
  1974年   17027篇
  1973年   16337篇
  1972年   15500篇
  1971年   14393篇
  1970年   13359篇
  1969年   12860篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
In the 6th Basic Plan for Long-Term Electricity Supply and Demand (6th BPE) for Korea, for the first time, the environmental costs of air pollution caused by oxides of sulfur (SOx), oxides of nitrogen (NOx), and particulate matters (PM) from power plants were estimated and included. However, several deficiencies in evaluating the environmental costs were found. In this study, (1) the validity of the environmental costs used in the 6th BPE was assessed, (2) a systematic approach was suggested and used to improve the environmental costs estimation, and (3) the sensitivity of the cost of generating electricity to the environmental costs by fuel type with the proposed approach was discussed. We found that the applied environmental costs used in the 6th BPE did not fully include the demographic characteristics of Korea. By applying more realistic parameter values, it was found that the newly estimated environmental cost was about 23 times higher than the cost estimated in the original 6th BPE for coal-fired power plants and about 1.5 times higher for liquefied natural gas (LNG)-fired power plants, suggesting that LNG-fired power plants are more economical if using more realistic environmental costs. Thus, it is critical to check the validity of parameter values when calculating environmental costs.  相似文献   
64.
65.
DNA methylation at CpG dinucleotides is an important epigenetic regulator common to virtually all mammalian cell types, but recent evidence indicates that during early postnatal development neuronal genomes also accumulate uniquely high levels of two alternative forms of methylation, non-CpG methylation and hydroxymethylation. Here we discuss the distinct landscape of DNA methylation in neurons, how it is established, and how it might affect the binding and function of protein readers of DNA methylation. We review studies of one critical reader of DNA methylation in the brain, the Rett syndrome protein methyl CpG-binding protein 2 (MeCP2), and discuss how differential binding affinity of MeCP2 for non-CpG and hydroxymethylation may affect the function of this methyl-binding protein in the nervous system.  相似文献   
66.
67.
A 17‐year‐old boy presented with recurring severe dermatitis of the face of 5‐months duration that resembled impetigo. He had been treated with several courses of antibiotics without improvement. Biopsy showed changes consistent with allergic contact dermatitis and patch testing later revealed sensitization to benzoyl peroxide, which the patient had been using for the treatment of acne vulgaris.  相似文献   
68.
Abstract

Objective: To understand the origin of extremely high gonadotropin levels in a perimenopausal woman.

Methods: A 52-year-old woman with a 2?months of amenorrhea followed spontaneous menstrual cycles recovery was referred to our outpatient clinic with elevated follicle-stimulating hormone (FSH, 483 mUI/ml), luteinizing hormone (LH, 475 mUI/ml) and prolactin (PRL, 173?ng/ml). She was known to take levosulpiride. The gonadotropin levels did not fit with the clinical features.

Results: A gonadotroph tumor was ruled out. Further analysis confirmed constantly high FSH, LH and PRL levels. The measurements were repeated using different analytical platforms with different results. After serial dilutions, nonlinearity was present suggesting an immunoassay interference. After post-polyethylene glycol recovery, hormone levels appeared in the normal range. Anti-goat antibodies were recognized in the serum of the patient.

Conclusions: This case report shows a case of falsely abnormal high gonadotropin and PRL levels in a woman during menopause transition. In the clinical practice the evaluation of gonadotropin profile is not recommended at this age, but the abnormal levels stimulated further evaluation. An interference in the assay due to anti-goat antibodies resulted in abnormally high level of FSH and LH. A strict collaboration between clinicians and the laboratory is needed, when laboratory findings do not correspond to clinical findings.  相似文献   
69.
70.
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