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   26854篇
  免费   1293篇
  国内免费   133篇
耳鼻咽喉   206篇
儿科学   472篇
妇产科学   410篇
基础医学   3521篇
口腔科学   865篇
临床医学   1875篇
内科学   6394篇
皮肤病学   457篇
神经病学   2337篇
特种医学   1193篇
外科学   4295篇
综合类   99篇
一般理论   1篇
预防医学   713篇
眼科学   477篇
药学   2013篇
中国医学   72篇
肿瘤学   2880篇
  2023年   125篇
  2022年   235篇
  2021年   414篇
  2020年   253篇
  2019年   370篇
  2018年   436篇
  2017年   327篇
  2016年   436篇
  2015年   450篇
  2014年   610篇
  2013年   754篇
  2012年   1175篇
  2011年   1375篇
  2010年   692篇
  2009年   672篇
  2008年   1196篇
  2007年   1248篇
  2006年   1184篇
  2005年   1263篇
  2004年   1217篇
  2003年   1182篇
  2002年   1247篇
  2001年   971篇
  2000年   982篇
  1999年   978篇
  1998年   352篇
  1997年   288篇
  1996年   256篇
  1995年   239篇
  1994年   210篇
  1993年   207篇
  1992年   683篇
  1991年   591篇
  1990年   615篇
  1989年   603篇
  1988年   524篇
  1987年   486篇
  1986年   477篇
  1985年   415篇
  1984年   302篇
  1983年   253篇
  1981年   105篇
  1980年   108篇
  1979年   248篇
  1978年   153篇
  1977年   142篇
  1975年   106篇
  1972年   111篇
  1971年   104篇
  1969年   105篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
993.
994.
Present study aimed to investigate the impact of anti-inflammatory cytokines provoked by the hemoglobin scavenger receptor, CD163, on left ventricular (LV) functional recovery after successful reperfusion in patients with acute myocardial infarction (AMI). Intraplaque hemorrhage accelerates plaque destabilization. Extracellular hemoglobin is cleared by CD163, a macrophage scavenger receptor. This process provokes secretion of anti-inflammatory atheroprotective cytokine, interleukin (IL)-10. In 40 patients with the first AMI, coronary atherothrombotic debris was retrieved during percutaneous coronary intervention (PCI), stained with antibodies to CD163 and IL-10. LV function was determined by echocardiography before PCI and 6 months after PCI. %CD163 was defined as ratio of CD163 (+)-cells to whole cells. %IL-10 was expressed as the ratio of positively stained areas per total tissue. Patients were divided into two groups depending on the amount of CD163 (+)-cells: CD163 > 10 % (CD163high, n = 20) and CD163 ≤ 10 % (CD163low, n = 20). CD163high group had significantly higher %IL-10. Final thrombolysis in myocardial infarction (TIMI) flow grade was significantly lower in CD163high group. In subgroups with the final TIMI-3 flow (CD163high-Reflow, n = 15 and CD163low-Reflow, n = 20), the time to reperfusion, infarct size, LV dimensions and fractional shortening (%FS) before PCI were similar. Significant correlation was observed between %IL10 and changes in LV dimensions (diastole, r = ?0.49, P = 0.01; systole, r = ?0.65, P < 0.01) or %FS (r = 0.51, P < 0.01) at 6 months after PCI. Plaque with CD163(+)-macrophages could impair distal flow after primary PCI. However, CD163(+)-macrophages enhance the anti-inflammatory cytokine expression that aids in ventricular functional recovery if distal flow can be achieved by successful reperfusion.  相似文献   
995.
Infliximab (IFX) is used as a therapeutic agent for ulcerative colitis (UC) and Crohn's disease (CD). Although the dosage regimen has been established through clinical trial experience, it has yet to be assessed with a pharmacokinetic and pharmacodynamic model. The present study analysed sequential changes of clinical response in patients with ulcerative colitis and Crohn's disease following repeated administrations of infliximab using the pharmacokinetic/pharmacodynamic model. In addition, the dosage regimen presently used for patients with ulcerative colitis was evaluated, as well as the potential efficacy gained by increasing the dose and/or reducing the interval of administration for patients with Crohn's disease. Furthermore, the possibility of evaluating the difference between both diseases with regard to the efficacy of infliximab was investigated. Sequential changes in the clinical response values obtained with our model were in good agreement with the observed values following administration of infliximab in patients with ulcerative colitis and Crohn's disease. The results showed the importance of a loading dose for patients with ulcerative colitis, as well as the efficacy of increasing the dose and reducing the interval for patients with Crohn's disease. Also, the efficacy of infliximab for both diseases is suggested to be similar. In conclusion, our results show a possible modeling scenario that can accommodate the clinical response to infliximab administered for ulcerative colitis and Crohn's disease. Furthermore, it provides confirmation for the present dosage regimens given for these diseases.  相似文献   
996.
The plasma renin activity (PRA) is affected by a number of environmental factors. However, significant heritability has been shown for the activity. A hypothesis that a candidate regulatory single-nucleotide polymorphism, C-5312T, of human renin gene should have a significant effect on PRA was elucidated and updating of independent determinants of PRA was attempted.Cross sectional study.Outpatient study.We enrolled consecutive 810 subjects who had consulted our hospitals for lifestyle-related diseases.Genotypes were assayed with genomic DNA for C-5312T. Among the genetic variants, the difference of PRA was evaluated. Monovariate linear regression analysis was performed to test the correlation between PRA and clinical variables. Finally, stepwise multiple regression analysis was performed to evaluate the independent determinants.On comparing 2 genotype groups, CC/CT and T allele homozygote, the geometric means of PRA were 0.778 and 0.941 ng/ml/h, respectively (F = 5.992, P = 0.015). Monovariate linear regression analysis revealed that a number of variables have a significant correlation with the activity, including urinary salt excretion. A stepwise multivariate regression analysis revealed that renin C-5312T variant (TT) is one of the independent determinants of PRA.Thus, for the first time, a human renin gene variant was associated with a significant increase in PRA as a genetic factor and the independent determinants for the activity were updated including genetic factor.  相似文献   
997.
998.
999.

Background

In a genome-wide association study of autism, zinc finger protein 804A (ZNF804A) single nucleotide polymorphisms (SNPs) were found to be nominally associated in verbally deficient individuals with autism. Zinc finger protein 804A copy number variations (CNVs) have also been observed in individuals with autism. In addition, ZNF804A is known to be involved in theory of mind (ToM) tasks, and ToM deficits are deemed responsible for the communication and social challenges faced by individuals with autism. We hypothesized that ZNF804A could be a risk gene for autism.

Methods

We examined the genetic association and CNVs of ZNF804A in 841 families in which 1 or more members had autism. We compared the expression of ZNF804A in the postmortem brains of individuals with autism (n = 8) and controls (n = 13). We also assessed in vitro the effect of ZNF804A silencing on the expression of several genes known to be involved in verbal efficiency and social cognition.

Results

We found that rs7603001 was nominally associated with autism (p = 0.018). The association was stronger (p = 0.008) in the families of individuals with autism who were verbally deficient (n = 761 families). We observed ZNF804A CNVs in 7 verbally deficient boys with autism. In ZNF804A knockdown cells, the expression of synaptosomal-associated protein, 25kDa (SNAP25) was reduced compared with controls (p = 0.009). The expression of ZNF804A (p = 0.009) and SNAP25 (p = 0.009) were reduced in the anterior cingulate gyrus (ACG) of individuals with autism. There was a strong positive correlation between the expression of ZNF804A and SNAP25 in the ACG (p < 0.001).

Limitations

Study limitations include our small sample size of postmortem brains.

Conclusion

Our results suggest that ZNF804A could be a potential candidate gene mediating the intermediate phenotypes associated with verbal traits in individuals with autism.  相似文献   
1000.
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