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   200278篇
  免费   19071篇
  国内免费   11742篇
耳鼻咽喉   2038篇
儿科学   2094篇
妇产科学   2656篇
基础医学   24626篇
口腔科学   3596篇
临床医学   25469篇
内科学   30308篇
皮肤病学   2583篇
神经病学   10679篇
特种医学   7671篇
外国民族医学   97篇
外科学   21121篇
综合类   30059篇
现状与发展   39篇
一般理论   24篇
预防医学   12801篇
眼科学   5315篇
药学   20936篇
  256篇
中国医学   11540篇
肿瘤学   17183篇
  2025年   47篇
  2024年   2639篇
  2023年   4049篇
  2022年   8539篇
  2021年   10674篇
  2020年   8082篇
  2019年   6845篇
  2018年   7175篇
  2017年   6531篇
  2016年   6380篇
  2015年   9557篇
  2014年   11569篇
  2013年   10853篇
  2012年   15774篇
  2011年   16717篇
  2010年   10719篇
  2009年   8299篇
  2008年   10991篇
  2007年   10349篇
  2006年   9842篇
  2005年   9458篇
  2004年   6158篇
  2003年   5547篇
  2002年   4637篇
  2001年   3653篇
  2000年   3840篇
  1999年   3879篇
  1998年   2322篇
  1997年   2367篇
  1996年   1810篇
  1995年   1747篇
  1994年   1529篇
  1993年   926篇
  1992年   1288篇
  1991年   1126篇
  1990年   905篇
  1989年   855篇
  1988年   769篇
  1987年   633篇
  1986年   462篇
  1985年   400篇
  1984年   193篇
  1983年   164篇
  1982年   98篇
  1981年   128篇
  1980年   80篇
  1979年   109篇
  1978年   52篇
  1977年   52篇
  1974年   44篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
A deficiency of complement factor H may lead to excessive consumption of C3 and an increase in C3b deposition, which are important pathological characteristics of lupus nephritis. Complement factor H-related proteins (CFHRs), comprising CFHR1 to CFHR5 (CFHR1–5), are members of the wider factor H/CFHR family. Their role in lupus nephritis remains unclear. In this study, we compared circulating levels of CFHR1–5 in 152 patients diagnosed with lupus nephritis and 20 unrelated healthy individuals to explore the relationship between the expression of CFHR1–5 and development of the disease. We found that plasma levels of CFHR3 and CFHR5 were higher in patients with lupus nephritis than in healthy individuals; also, CFHR3 and CFHR5 concentrations increased with increasing systemic lupus erythematosus disease activity index (SLEDAI) values (P < 0.05). Pearson's and Spearman's correlation test results confirmed that plasma CFHR3 and CFHR5 levels in lupus nephritis patients were positively correlated with proteinuria and levels of creatinine (Cr) and anti-dsDNA (correlation coefficients = 0.491–0.717, P < 0.05), while they were negatively correlated with plasma C3 levels and eGFR [correlation coefficients = –(0.706–0.788), P < 0.05]. Receiver operating characteristic (ROC) curve analysis results confirmed that plasma CFHR3 and CFHR5 levels were predictive of SLEDAI values and disease end points (area under the curve = 0.664–0.884, P < 0.05), with patients with both high CFHR3 and high CFHR5 exhibiting the shortest progression-free survival. Thus, both CFHR3 and CFHR5 are of prognostic value in lupus nephritis status.  相似文献   
63.
Liang  Xiongyan  Gu  Yufang  Chen  Xueyang  Li  Tuofan  Gao  Yulong  Wang  Xiaomei  Fang  Chun  Fang  Shouguo  Yang  Yuying 《Virus genes》2019,55(5):726-733
Virus Genes - Avian leukosis virus (ALV) caused tremendous economic losses to poultry industry all over the world, especially in China. One natural recombinant ALV strain, designated as HB2015032,...  相似文献   
64.
Wang  Mao  Zhao  Yuanjun  Yang  Chengzhong 《Parasitology research》2019,118(3):1061-1066
Parasitology Research - Samples of Myxobolus lentisuturalis were found in the gallbladder of Carassius auratus in Chongqing, China, without obvious disease symptoms, which were different from...  相似文献   
65.
Ye  Shu  Xia  Ningbo  Zhao  Pengfei  Yang  Jichao  Zhou  Yanqin  Shen  Bang  Zhao  Junlong 《Parasitology research》2019,118(3):935-944
Parasitology Research - Toxoplasma gondii is a ubiquitous parasitic protozoan infecting humans and a wide variety of animals. Fast-replicating tachyzoites during acute infection and slowly growing...  相似文献   
66.
BackgroundTo determine whether 3D-CT imaging technique is valid and reproducible compared to conventional CT measurement technique (CCT) for the detection of a femoropatellar instability.MethodsPatients who had undergone surgery for femoropatellar instability (patellar instability group) between 2010 and 2016 (n = 37 knees of 35 patients) were retrospectively enrolled. For the matched control group, patients who had acute anterior cruciate ligament injury (< 4 weeks previously; n = 30) were recruited. Preoperative CT data had been obtained in all patients. Inter-rater reliability was calculated for both measurement protocols, and inter-method reliability was calculated between the two imaging modalities. The results are reported using intraclass correlation coefficients (ICCs) and Bland–Altman 95% limits of agreement.ResultsAll patients in the patellar instability group had femoral trochlear dysplasia (Dejour types A: four, B: 19, C: seven, and D: six), but no dysplasia was noted in the control group. In the patellar instability group, the CCT technique showed a poor inter-rater agreement (ICC = 0.74), and the 3D-CT technique still showed excellent inter-rater agreement (ICCs = 0.91). In the sub-analysis of the patellar instability group according to the trochlear dysplasia grade, ICCs were markedly decreased with severe trochlear dysplasia when using CCT technique; however, the 3D-CT technique could provide excellent reliability even with severe trochlear dysplasia.ConclusionThe 3D-CT imaging technique for the measurement of the TT–TG distance can be suggested as a better measurement technique for patellar instability patients with bone abnormality.  相似文献   
67.
Yin  Nannan  Yang  Yaping  Wang  Xiaoyan  Yang  Chao  Ma  Xiaofei  Shaukat  Aftab  Zhao  Gan  Deng  Ganzhen 《Inflammation research》2019,68(3):231-240
Objective

In both humans and animals, endometritis is severe inflammation of the uterus, and it causes great economic losses in dairy cow production. MicroRNAs have been reported to play an important role in various inflammatory diseases. However, the regulatory mechanisms of miR-19a in endometritis remain unclear. Thus, the aims of this study are to investigate the role of miR-19a in a mouse model of lipopolysaccharide (LPS)-induced endometritis and elucidate the possible mechanisms in bovine endometrial epithelial cells (bEECs).

Methods and results

Histological analysis showed that LPS induced severe pathological changes, suggesting that the endometritis mouse model was well established. The qPCR assay indicated that miR-19a expression in the uterine tissues of mice with endometritis and in bEECs with LPS stimulation was significantly reduced. The overexpression of miR-19a significantly decreased the expression of inflammatory cytokines (TNF-α, IL-6 and IL-1β) and the phosphorylation of NF-κB p65 and IκBα. Similar results were also obtained following the knockdown of TBK1. Furthermore, a dual luciferase reporter assay further validated that miR-19a inhibited TBK1 expression by binding directly to the 3′-UTR of TBK1.

Conclusion

We demonstrated that miR-19a has anti-inflammatory effects and mediates the negative regulation of the NF-κB Pathway in LPS-induced endometritis by targeting TBK1.

  相似文献   
68.
Yang  Fan  Li  Yang  Zou  Weilong  Xu  Yanan  Wang  Hao  Wang  Wei  Zhao  Yong 《Inflammation research》2019,68(7):545-555
Inflammation Research - Efficient production of monocytic myeloid-derived suppressor cells (M-MDSCs) with stable immunosuppressive function is crucial for immunomodulatory cell therapy for many...  相似文献   
69.
Liu  Yixin  Wei  Wei  Wang  Yang  Wan  Chunyou  Bai  Yingyu  Sun  Xuguo  Ma  Jun  Zheng  Fang 《Inflammation research》2019,68(7):597-611
Inflammation Research - The present study was undertaken to validate whether TNF-α and calreticulin (CRT) serve as dual signaling to activate nucleotide-binding oligomerization domain-,...  相似文献   
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