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   1814篇
  免费   144篇
  国内免费   7篇
耳鼻咽喉   45篇
儿科学   69篇
妇产科学   30篇
基础医学   216篇
口腔科学   38篇
临床医学   168篇
内科学   374篇
皮肤病学   41篇
神经病学   105篇
特种医学   72篇
外科学   371篇
综合类   35篇
预防医学   106篇
眼科学   46篇
药学   124篇
中国医学   10篇
肿瘤学   115篇
  2023年   31篇
  2022年   77篇
  2021年   101篇
  2020年   69篇
  2019年   94篇
  2018年   95篇
  2017年   61篇
  2016年   61篇
  2015年   77篇
  2014年   84篇
  2013年   81篇
  2012年   139篇
  2011年   131篇
  2010年   90篇
  2009年   64篇
  2008年   81篇
  2007年   79篇
  2006年   70篇
  2005年   58篇
  2004年   73篇
  2003年   67篇
  2002年   43篇
  2001年   17篇
  2000年   16篇
  1999年   22篇
  1998年   13篇
  1997年   5篇
  1996年   5篇
  1995年   3篇
  1992年   8篇
  1991年   9篇
  1990年   7篇
  1989年   7篇
  1988年   3篇
  1987年   3篇
  1986年   10篇
  1985年   11篇
  1984年   4篇
  1983年   4篇
  1982年   9篇
  1979年   10篇
  1978年   8篇
  1977年   3篇
  1976年   7篇
  1975年   7篇
  1974年   14篇
  1973年   7篇
  1972年   7篇
  1970年   4篇
  1966年   2篇
排序方式: 共有1965条查询结果,搜索用时 17 毫秒
51.
B‐type natriuretic peptide (BNP) levels have been shown to predict ventricular arrhythmia (VA) and sudden death in patients with heart failure. We sought to determine whether BNP levels before left ventricular assist device (LVAD) implantation can predict VA post LVAD implantation in advanced heart failure patients. We conducted a retrospective study consisting of patients who underwent LVAD implantation in our institution during the period of May 2009–March 2013. The study was limited to patients receiving a HeartMate II or HeartWare LVAD. Acute myocardial infarction patients were excluded. We compared between the patients who developed VA within 15 days post LVAD implantation to the patients without VA. A total of 85 patients underwent LVAD implantation during the study period. Eleven patients were excluded (five acute MI, four without BNP measurements, and two discharged earlier than 13 days post LVAD implantation). The incidence of VA was 31%, with 91% ventricular tachycardia (VT) and 9% ventricular fibrillation. BNP remained the single most powerful predictor of VA even after adjustment for other borderline significant factors in a multivariate logistic regression model (P < 0.05). BNP levels are a strong predictor of VA post LVAD implantation, surpassing previously described risk factors such as age and VT in the past.  相似文献   
52.
53.
54.
Even with continuous vector control, dengue is still a growing threat to public health in Southeast Asia. Main causes comprise difficulties in identifying productive breeding sites and inappropriate targeted chemical interventions. In this region, rural families keep live birds in backyards and dengue mosquitoes have been reported in containers in the cages. To focus on this particular breeding site, we examined the capacity of bird fecal matter (BFM) from the spotted dove, to support Aedes albopictus larval growth. The impact of BFM larval uptake on some adult fitness traits influencing vectorial capacity was also investigated. In serial bioassays involving a high and low larval density (HD and LD), BFM and larval standard food (LSF) affected differently larval development. At HD, development was longer in the BFM environment. There were no appreciable mortality differences between the two treatments, which resulted in similar pupation and adult emergence successes. BFM treatment produced a better gender balance. There were comparable levels of blood uptake and egg production in BFM and LSF females at LD; that was not the case for the HD one, which resulted in bigger adults. BFM and LSF females displayed equivalent lifespans; in males, this parameter was shorter in those derived from the BFM/LD treatment. Taken together these results suggest that bird defecations successfully support the development of Ae. albopictus. Due to their cryptic aspects, containers used to supply water to encaged birds may not have been targeted by chemical interventions.  相似文献   
55.
Myocardial infarction (MI) denotes the death of cardiac myocytes due to extended ischemia. Myocardial reperfusion is the restoration of coronary blood flow after a period of coronary occlusion. Reperfusion has the potential to salvage ischemic myocardium but paradoxically can cause injury, a phenomenon called as ‘reperfusion injury’ (IR). Standard histologic, immunohistochemical and Elisa techniques were used to study the histopathologic, oxidative, apoptotic and inflammatory changes in MI and IR. The IL-6 levels in the LV of the MI group were significantly raised as compared to the IR group (P=0.0008). Plasma IL-6 was also significantly increased in the MI group as compared to the IR group (P=0.031). MI model was also associated with increase in the neutrophil polymorphs number in the infarction related myocardium as compared to the re-perfused myocardium. A significant increase in troponin I level in the MI group as compared to the IR group is also seen (P=0.0001). Our IR model showed enhanced pro-apoptotic mediators like cleaved caspase-3 (P=0.005) and cytochrome c in the myocardium as compared to the MI model. In conclusion, myocardial damage in MI is mainly due to ischemic necrosis and inflammatory mechanisms while apoptosis is the main mechanism of cell death in IR in addition to limited ischemic necrosis.  相似文献   
56.
BACKGROUND. Individuals treated with the cholesteryl ester transfer protein (CETP) inhibitor anacetrapib exhibit a reduction in both LDL cholesterol and apolipoprotein B (ApoB) in response to monotherapy or combination therapy with a statin. It is not clear how anacetrapib exerts these effects; therefore, the goal of this study was to determine the kinetic mechanism responsible for the reduction in LDL and ApoB in response to anacetrapib.METHODS. We performed a trial of the effects of anacetrapib on ApoB kinetics. Mildly hypercholesterolemic subjects were randomized to background treatment of either placebo (n = 10) or 20 mg atorvastatin (ATV) (n = 29) for 4 weeks. All subjects then added 100 mg anacetrapib to background treatment for 8 weeks. Following each study period, subjects underwent a metabolic study to determine the LDL-ApoB-100 and proprotein convertase subtilisin/kexin type 9 (PCSK9) production rate (PR) and fractional catabolic rate (FCR).RESULTS. Anacetrapib markedly reduced the LDL-ApoB-100 pool size (PS) in both the placebo and ATV groups. These changes in PS resulted from substantial increases in LDL-ApoB-100 FCRs in both groups. Anacetrapib had no effect on LDL-ApoB-100 PRs in either treatment group. Moreover, there were no changes in the PCSK9 PS, FCR, or PR in either group. Anacetrapib treatment was associated with considerable increases in the LDL triglyceride/cholesterol ratio and LDL size by NMR.CONCLUSION. These data indicate that anacetrapib, given alone or in combination with a statin, reduces LDL-ApoB-100 levels by increasing the rate of ApoB-100 fractional clearance.TRIAL REGISTRATION. ClinicalTrials.gov NCT00990808.FUNDING. Merck & Co. Inc., Kenilworth, New Jersey, USA. Additional support for instrumentation was obtained from the National Center for Advancing Translational Sciences (UL1TR000003 and UL1TR000040).  相似文献   
57.
58.
Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a serious congenital malformation. Reports about asymptomatic, incidentally discovered ALCAPA in adults are scarce. We describe a patient with no known pre-existing cardiac condition admitted to our hospital with coronavirus disease 2019 (COVID-19) and was incidentally found to have ALCAPA. To the best of our knowledge, this is the first reported case of incidentally discovered ALCAPA in a COVID-19 patient and highlights the importance of appropriate investigation of the coronary status by Multidetector Cardiac Computed Tomographic Angiography (MDCCTA) in individuals with asymptomatic left ventricular dysfunction. The presentation of this case, discussion and literature review serves to iterate the necessity of appropriately investigating patients with asymptomatic LV dysfunction.  相似文献   
59.
60.
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