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   17848篇
  免费   940篇
  国内免费   107篇
耳鼻咽喉   237篇
儿科学   339篇
妇产科学   157篇
基础医学   2197篇
口腔科学   297篇
临床医学   1209篇
内科学   4675篇
皮肤病学   947篇
神经病学   1208篇
特种医学   908篇
外科学   3192篇
综合类   75篇
一般理论   2篇
预防医学   392篇
眼科学   179篇
药学   1137篇
中国医学   24篇
肿瘤学   1720篇
  2023年   116篇
  2022年   220篇
  2021年   345篇
  2020年   208篇
  2019年   289篇
  2018年   355篇
  2017年   306篇
  2016年   372篇
  2015年   392篇
  2014年   510篇
  2013年   648篇
  2012年   1007篇
  2011年   1062篇
  2010年   613篇
  2009年   481篇
  2008年   878篇
  2007年   979篇
  2006年   937篇
  2005年   967篇
  2004年   955篇
  2003年   926篇
  2002年   884篇
  2001年   475篇
  2000年   430篇
  1999年   412篇
  1998年   230篇
  1997年   190篇
  1996年   203篇
  1995年   152篇
  1994年   118篇
  1993年   94篇
  1992年   249篇
  1991年   257篇
  1990年   255篇
  1989年   258篇
  1988年   248篇
  1987年   230篇
  1986年   219篇
  1985年   216篇
  1984年   156篇
  1983年   109篇
  1982年   64篇
  1981年   66篇
  1979年   117篇
  1978年   65篇
  1977年   50篇
  1975年   51篇
  1972年   55篇
  1969年   49篇
  1968年   50篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
miRNA‐221 (miR‐221) is known to be abnormally expressed in many human cancers. The serum levels of miR‐221 have been reported as a tumor marker for malignant melanoma (MM). We hypothesized that the hair shaft miR‐221 levels may be increased in patients with MM. We therefore assessed the possibility that hair shaft miR‐221 levels could be a marker for MM. The hair shaft miR‐221 levels were significantly higher in patients with MM than controls. The rates of increased hair shaft miR‐221 levels above the cut‐off value were comparable to those of serum 5‐S‐CD, which is a tumor marker commonly used for MM. Measurements of the hair shaft miR‐221 levels could have potential clinical value in the detection of MM. This is the first report investigating the hair shaft levels of an miRNA in patients with MM. Our investigations offer new insight into the relationship between miR‐221 and MM, and may provide a new, non‐invasive way to screen for melanoma.  相似文献   
5.
6.
Adolescence is a vulnerable period for developing anxiety-related mental disorders such as post-traumatic stress disorder (PTSD), which requires a long-term course of therapy when a traumatic event has been experienced during childhood. However, the biological mechanism underlying these age-dependent characteristics remains unclear. In the present study, we used early adolescent, late adolescent and adult (4-, 8-, and 15-week old) male mice to examine age differences in fear memory, fear extinction, and spontaneous recovery of fear. We also measured the activation of extracellular signal-regulated kinase (ERK) 2 in the dorsal hippocampus (dHip) and the basolateral amygdala (BLA) following a spontaneous recovery test. Our major findings were as follows: (1) early adolescent and adult mice did not recover the fear response; only late adolescent mice recovered the fear response. (2) The ERK2 in the dHip was more activated after the spontaneous recovery test in late adolescent mice than in adult mice, and the ERK2 in the BLA was more activated after the spontaneous recovery test in adult mice than in late adolescent mice. These results suggest that there exists a unique period in which spontaneous recovery occurs and that these late adolescent behavioral signatures may be related to alteration in the ERK2 phosphorylation in the dHip and BLA.  相似文献   
7.
Although many single nucleotide polymorphism (SNP) studies have reported an association of atopy, allergic diseases and total serum immunoglobulin E (IgE) levels, almost all of these studies sought risk factors for the onset of these allergic diseases. Furthermore, many studies have analyzed a single gene and hardly any have analyzed environmental factors. In these analyses, the results could be masked and the effects of other genes and environmental factors may be decreased. Here, we described the correlation between four genes [interleukin (IL)-4 (C-590T), IL-4 receptor (A1652G), FCER1B (G6842A) and STAT6 (G2964A)] in connection with IgE production; the role of IL-10 (C-627A) as a regulatory cytokine of allergy; and the severity of food allergy (FA) and atopic eczema (AE) in 220 Japanese allergic children. In addition to these SNPs, environmental factors, i.e., patient's attitude, indoor environment, and so on, were also investigated in this study. Our study was retrospective, and the correlation was analyzed by our defined clinical scores divided into three terms: worst symptoms, recent symptoms and general amelioration at the most recent examination during the disease course. Our results indicated that IL-10 AA, the genotype with lower IL-10 production, is associated with higher IgE levels in the serum (p < 0.0001, estimate; 0.912). Marginal liver abnormalities were observed in the subject group with both FA and AE (p < 0.1191, estimate; 0.1490). Our defined clinical scores enabled evaluation of various aspects of disease severity. Based on the scores, while no single SNP selected in this study determined severity, the combination of the SNP with laboratory data and environmental factors appeared to determine severity.  相似文献   
8.
9.
A 23-year-old man was admitted for treatment of acute exacerbation of ileitis and perianal abscess caused by Crohn's disease. After incision and drainage of the abscess, coupled with antibiotic therapy, 6-mercaptopurine (6-MP) was commenced. His white blood cell (WBC) count on day 12 after initiation of 6-MP was not decreased. However, on day 24 he was re-admitted because of severe myelosuppression (WBC: 300/microl), which was complicated by the recurrence of the perianal abscess. Myelosuppression was prolonged and required the administration of granulocyte colony stimulating factor (G-CSF). G-CSF was continued for 17 days to achieve recovery of his WBC count to a normal level.  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