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   3440227篇
  免费   293094篇
  国内免费   13891篇
耳鼻咽喉   48301篇
儿科学   110796篇
妇产科学   90537篇
基础医学   546777篇
口腔科学   93385篇
临床医学   305732篇
内科学   610118篇
皮肤病学   91357篇
神经病学   292711篇
特种医学   136696篇
外国民族医学   391篇
外科学   539701篇
综合类   102579篇
现状与发展   23篇
一般理论   2206篇
预防医学   285801篇
眼科学   79054篇
药学   239351篇
  20篇
中国医学   9790篇
肿瘤学   161886篇
  2021年   55045篇
  2020年   35126篇
  2019年   58180篇
  2018年   71377篇
  2017年   53981篇
  2016年   59633篇
  2015年   73865篇
  2014年   108215篇
  2013年   173574篇
  2012年   90436篇
  2011年   90609篇
  2010年   116551篇
  2009年   121151篇
  2008年   78711篇
  2007年   82193篇
  2006年   92997篇
  2005年   88898篇
  2004年   90643篇
  2003年   81974篇
  2002年   72373篇
  2001年   104496篇
  2000年   97231篇
  1999年   97471篇
  1998年   65343篇
  1997年   63022篇
  1996年   60990篇
  1995年   56412篇
  1994年   50700篇
  1993年   47173篇
  1992年   69644篇
  1991年   66864篇
  1990年   64253篇
  1989年   63402篇
  1988年   59376篇
  1987年   57811篇
  1986年   55157篇
  1985年   55119篇
  1984年   49710篇
  1983年   45748篇
  1982年   42195篇
  1981年   39676篇
  1980年   37379篇
  1979年   41828篇
  1978年   36475篇
  1977年   33435篇
  1976年   30787篇
  1975年   30037篇
  1974年   31260篇
  1973年   30064篇
  1972年   28340篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
952.
953.
954.
We report a case of dichorionic, diamniotic twins who developed similar erythematous, annular, erosive plaques in the inguinal folds in the first few weeks of life that were refractory to topical antifungals and oral antibiotics. The twins were found to have high transaminase levels, antinuclear antibody positivity, and anti‐SSS/Ro) and anti‐SSB/La autoantibodies. The rash resolved without scarring by 7 months of age with the use of low‐potency topical corticosteroids. We suggest that physicians consider neonatal lupus erythematosus in neonates with atypical eruptions occurring in sun‐protected skin.  相似文献   
955.
Pediatric dermatology is one of the smallest subspecialties, and expanding the availability of care is of great interest. Teledermatology has been proposed as a way to expand access and improve care delivery, but no current assessment of pediatric teledermatology exists. The objective of the current study was to assess usage and perspectives on pediatric teledermatology. Surveys were distributed electronically to all 226 board‐certified U.S. pediatric dermatologists; 44% (100/226) responded. Nearly all respondents (89%) have experience with teledermatology. Formal teledermatology reimbursement success rates have increased to 35%. Respondents were positive about teledermatology's present and future prospects, and 41% want to use teledermatology more often, although they viewed teledermatology as somewhat inferior to in‐person care regarding accuracy of diagnosis and appropriation of management plans. Significant differences were found between formal teledermatology users and nonusers in salary structure, practice environment, sex, and region. Substantial increases in pediatric teledermatology have occurred in the last 5 to 10 years, and there remains cause for optimism for teledermatology's future. Concerns about diagnostic confidence and care quality indicate that teledermatology may be best for care of patients with characteristic clinical presentations or management of patients with established diagnoses.  相似文献   
956.
We present the case of 7‐year‐old African American girl with loose anagen syndrome. Although this is a common cause of hair loss in Caucasian children, and there have been reports of cases occurring in dark‐skinned children of North African and Middle Eastern descent, to our knowledge there have been no cases reported in black children of sub‐Saharan African ancestry. We present this case to broaden the differential diagnosis of hair loss in African Americans.  相似文献   
957.
958.
959.
Synthetic amorphous silica (SAS) in its nanosized form is now used in food applications although the potential risks for human health have not been evaluated. In this study, genotoxicity and oxidative DNA damage of two pyrogenic (NM‐202 and 203) and two precipitated (NM‐200 and ‐201) nanosized SAS were investigated in vivo in rats following oral exposure. Male Sprague Dawley rats were exposed to 5, 10, or 20 mg/kg b.w./day for three days by gavage. DNA strand breaks and oxidative DNA damage were investigated in seven tissues (blood, bone marrow from femur, liver, spleen, kidney, duodenum, and colon) with the alkaline and the (Fpg)‐modified comet assays, respectively. Concomitantly, chromosomal damage was investigated in bone marrow and in colon with the micronucleus assay. Additionally, malondialdehyde (MDA), a lipid peroxidation marker, was measured in plasma. When required, a histopathological examination was also conducted. The results showed neither obvious DNA strand breaks nor oxidative damage with the comet assay, irrespective of the dose and the organ investigated. Similarly, no increases in chromosome damage in bone marrow or lipid peroxidation in plasma were detected. However, although the response was not dose‐dependent, a weak increase in the percentage of micronucleated cells was observed in the colon of rats treated with the two pyrogenic SAS at the lowest dose (5 mg/kg b.w./day). Additional data are required to confirm this result, considering in particular, the role of agglomeration/aggregation of SAS NMs in their uptake by intestinal cells. Environ. Mol. Mutagen. 56:218–227, 2015. © 2014 Wiley Periodicals, Inc.  相似文献   
960.
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