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   39010篇
  免费   4436篇
  国内免费   2602篇
耳鼻咽喉   296篇
儿科学   506篇
妇产科学   455篇
基础医学   4674篇
口腔科学   835篇
临床医学   4992篇
内科学   5523篇
皮肤病学   424篇
神经病学   1794篇
特种医学   1447篇
外国民族医学   17篇
外科学   4190篇
综合类   6820篇
现状与发展   12篇
一般理论   15篇
预防医学   2813篇
眼科学   1310篇
药学   3898篇
  56篇
中国医学   2373篇
肿瘤学   3598篇
  2024年   71篇
  2023年   688篇
  2022年   1118篇
  2021年   2057篇
  2020年   1706篇
  2019年   1467篇
  2018年   1505篇
  2017年   1361篇
  2016年   1266篇
  2015年   1909篇
  2014年   2395篇
  2013年   2228篇
  2012年   3104篇
  2011年   3398篇
  2010年   2168篇
  2009年   1826篇
  2008年   2202篇
  2007年   2133篇
  2006年   2171篇
  2005年   1838篇
  2004年   1336篇
  2003年   1149篇
  2002年   962篇
  2001年   830篇
  2000年   787篇
  1999年   811篇
  1998年   509篇
  1997年   463篇
  1996年   360篇
  1995年   321篇
  1994年   324篇
  1993年   186篇
  1992年   236篇
  1991年   188篇
  1990年   152篇
  1989年   194篇
  1988年   133篇
  1987年   133篇
  1986年   62篇
  1985年   71篇
  1984年   45篇
  1983年   30篇
  1982年   26篇
  1981年   26篇
  1980年   18篇
  1979年   25篇
  1978年   11篇
  1975年   8篇
  1974年   10篇
  1973年   4篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
22.
Sodium-glucose cotransporter-2 inhibitors (SGLT2 inhibitors) are a new type of drug for the treatment of diabetes, and they have been proven to have a good hypoglycemic effect. Several lines of clinical evidence have shown that SGLT2 inhibitors can significantly reduce the risks of atherosclerosis, hospitalization for heart failure, cardiovascular death, and all-cause mortality and delay the progression of chronic kidney disease. Because of the protective effects of SGLT2 inhibitors on the heart and kidney, they are being studied for the treatment of heart failure and chronic kidney disease in patients without diabetes. Therefore, it is necessary for cardiologists, patients with diabetes, and nephrologists to fully understand this type of drug. In this review, we summarize the following three aspects of SGLT2 inhibitors: the recent clinical evidence of their cardiovascular benefits, their mechanisms of action, and their safety.  相似文献   
23.
随着对肿瘤热疗和肿瘤免疫微环境(TIME)的深入研究,近年来热疗对TIME的作用越来越受到学者们的重视。本文就目前国内外研究进展,对热疗与TIME中几类主要免疫细胞和免疫相关细胞因子的影响及作用机制作一综述。全面而透彻的了解热疗对TIME的调控作用,有助于为肿瘤治疗提供新的思路和方法。  相似文献   
24.
目的研究枇杷叶紫珠Callicarpa kochiana的化学成分及其细胞毒活性和抗炎活性。方法枇杷叶紫珠90%丙酮提取物采用硅胶、Sephadex LH-20、MCI、ODS、重结晶、半制备HPLC进行分离纯化,根据理化性质及波谱数据鉴定所得化合物的结构。采用CCK8法、Griess法、ELISA法测定化合物4~5的细胞毒活性和抗炎活性。结果从中分离得到5个化合物,分别鉴定为3,7,3’,4’-tetramethyl-quercetin (1)、pachypodol (2)、14α-hydroxyisopimaric acid(3)、14α-hydroxy-7,15-isopimaradien-18-oic acid (4)、(16R)-16,17-dihydroxyphyllolladan-3-one (5)。化合物4在一定浓度范围内对7种肿瘤细胞具有不同程度的抑制作用,并可以减少RAW264. 7细胞NO、IL-10、MCP-1、TNF-α的释放量。结论化合物1~5均为首次从该植物中分离得到,化合物4具有细胞毒活性和抗炎活性。  相似文献   
25.
miRNAs是一类长度约为20~25个核苷酸,参与基因调控表达的内源性非编码RNA。miR-149作为miRNAs的重要成员,在多种肿瘤中表达异常,其表达水平与肿瘤细胞增殖、转移、凋亡、耐药、患者的早期诊断及预后密切相关。因此,miR-149有望成为新一类抗肿瘤治疗的靶点。  相似文献   
26.
Managing traumatic liver injury (TLI) is always challenging and demands precise clinical judgment. Currently, treatment of TLI in most circumstances is non-operative; however, surgical therapy might be required for severe TLI, particularly those that result in extensive blood loss. In the current institutional study carried out from June 1995 to April 2017, we describe our experience with 5 patients who received an orthotopic liver transplant for severe TLI. One patient passed away postoperatively from cerebral edema; 1 patient died of renal failure 4 years after the liver transplantation, and 3 patients are still alive. Based on our experience, we conclude that in patients with TLI, especially those with uncontrollable bleeding or those who develop liver failure, liver transplantation should be taken into consideration.  相似文献   
27.
BackgroundThe relationship between body mass index (BMI) and in-hospital mortality risk among patients with acute myocardial infarction (AMI) remains controversial.Methods and ResultsWe included 35,964 patients diagnosed with AMI in China Acute Myocardial Infarction registry between January 2013 and December 2016. Patients were categorized into 4 groups according to BMI level: BMI <18.5, 18.5–24.9, 25–30, and ≥30 kg/m2 for underweight, normal, overweight, and obese groups, respectively. Clinical data were extracted for each patient, and multivariable logistic regression analysis was used to examine the association between BMI level and in-hospital mortality. Compared with normal-weight patients, obese patients were younger, more often current smokers, and more likely to have hypertension, hyperlipidemia, and diabetes. Multivariable regression analysis results demonstrated that compared with normal group, underweight group had significantly higher in-hospital mortality (odds ratio [OR]: 1.34; 95% confidence interval [CI]: 1.06–1.69; p = 0.016), while overweight group (OR: 0.86; 95% CI: 0.77–0.97; p = 0.011) and obese group (OR: 0.65; 95% CI: 0.46–0.91; p = 0.013) had lower mortality. All subgroups showed a trend toward lower in-hospital mortality risk as BMI increased.ConclusionsOur study provided robust evidence supporting “obesity paradox” in a contemporary large-scale cohort of patients with AMI and demonstrated that increased BMI was independently associated with lower in-hospital mortality.  相似文献   
28.
目的 比较医用退热贴冷敷及卷心菜叶外敷2种方法对缓解产后生理性乳房胀痛的疗效。方法 选取2018年3-12月在产科住院的产后生理性乳房胀痛的患者100例为研究对象,将其随机分为对照组和观察组,各50例。对照组采用卷心菜叶外敷,观察组采用医用退热贴冷敷。结果 观察组产后生理性胀痛乳房评分低于对照组(Z=-2.568,P=0.010),乳房硬度优于对照组(Z=-4.361,P<0.001),使用维持时间长于对照组(t=19.804,P<0.001)。结论 医用退热贴冷敷用于产后生理性乳房胀痛效果理想,操作方法简单易行,实施方便,易被产妇接受,值得临床推广应用。  相似文献   
29.
Aim of the study: Parkinson’s disease (PD) is a neurodegenerative disorder. It is caused by the degeneration of dopaminergic neurons and the dopamine (DA) deletion in the substantia nigra pars compacta (SNpc). Morphine elevates the level of dopamine in the mesolimbic dopamine system and plays a role in alleviating PD symptoms. However, the molecular mechanism is still unclear. The aim of the study is to investigate the mechanism on morphine alleviating PD symptoms.

Materials and methods: The viability of PC12 cells was measured by using MTT assay. The expressions of tyrosine hydroxylase (TH), thioredoxin-1 (Trx-1), CyclinD1 and Cyclin-dependent kinase5 (Cdk5) were detected by Western Blot.

Results: In present study, we found that morphine increased the cell viability in PC12 cells. 1-methyl-4-phenylpyridi-nium (MPP+) reduced the cell viability and TH expression, which were reversed by morphine. MPP+ decreased the expressions of Trx-1, CyclinD1, Cdk5, which were restored by morphine. Moreover, the role of morphine in restoring the expressions of Trx-1, CyclinD1 and Cdk5 decreased by MPP+ was abolished by LY294002, phosphatidylinositol-3-kinase (PI3K)/Akt inhibitor.

Conclusions: These results suggest that morphine reverses effects induced by MPP þ through activating PI3K/Akt pathway.  相似文献   

30.
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