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   60300篇
  免费   5081篇
  国内免费   2253篇
耳鼻咽喉   129篇
儿科学   2476篇
妇产科学   297篇
基础医学   3205篇
口腔科学   226篇
临床医学   9561篇
内科学   14396篇
皮肤病学   337篇
神经病学   1902篇
特种医学   1565篇
外国民族医学   5篇
外科学   5638篇
综合类   12472篇
一般理论   1篇
预防医学   3089篇
眼科学   532篇
药学   6135篇
  73篇
中国医学   3148篇
肿瘤学   2447篇
  2024年   41篇
  2023年   1182篇
  2022年   1542篇
  2021年   2909篇
  2020年   2913篇
  2019年   1984篇
  2018年   1805篇
  2017年   2057篇
  2016年   2424篇
  2015年   2228篇
  2014年   4185篇
  2013年   4554篇
  2012年   3755篇
  2011年   4057篇
  2010年   3195篇
  2009年   2893篇
  2008年   2846篇
  2007年   3005篇
  2006年   2795篇
  2005年   2579篇
  2004年   2273篇
  2003年   2179篇
  2002年   1395篇
  2001年   1216篇
  2000年   1067篇
  1999年   816篇
  1998年   702篇
  1997年   626篇
  1996年   565篇
  1995年   529篇
  1994年   444篇
  1993年   319篇
  1992年   311篇
  1991年   256篇
  1990年   198篇
  1989年   224篇
  1988年   197篇
  1987年   155篇
  1986年   148篇
  1985年   236篇
  1984年   156篇
  1983年   104篇
  1982年   126篇
  1981年   109篇
  1980年   80篇
  1979年   73篇
  1978年   55篇
  1977年   43篇
  1976年   35篇
  1975年   21篇
排序方式: 共有10000条查询结果,搜索用时 84 毫秒
1.
目的:探讨上消化道出血患者急性应激障碍的影响因素。方法:运用病例对照研究法,选取天津市第五中心医院消化内科同期住院的270例患者为研究对象。通过斯坦福急性应激反应问卷(SASRQ)的调查,将发生急性应激障碍(ASD)的144例患者作为病例组,将未发生ASD的126例患者作为对照组。由专业人员对研究对象进行SASRQ、匹兹堡睡眠质量指数量表(PSQI)和疼痛视觉模拟评分尺(VAS)和一般资料的调查。比较病例组与对照组之间上述指标的差异。对ASD的影响因素进行Logistic 回归分析。结果:与对照组相比,病例组性别、年龄、婚姻状况、文化程度、主要照顾者关系、出血量、出血次数、出血诱因、疼痛程度、是否伴有其他症状、睡眠质量、是否恐惧是导致上消化道出血患者发生ASD的重要影响因素;多因素Logistic回归分析显示:性别(OR=0.435,95%CI:0.202~0.938)、文化程度(OR=0.573,95%CI:0.419~0.784)、出血诱因(OR=0.014,95%CI:0.000~0.410)、疼痛程度(OR=0.442,95%CI:0.221~0.886)、睡眠质量(OR=0.531,95%CI:0.379~0.744)为ASD的保护因素,年龄(OR=1.861,95%CI:1.119~3.095)、主要照顾者(OR=1.871,95%CI:1.172~2.987)、是否伴有其他症状(OR=33.219,95%CI:6.069~81.383)是ASD的危险因素。结论:年龄、主要照顾者关系、是否伴有其他症状是导致上消化道出血患者发生ASD的重要危险因素。  相似文献   
2.
目的 考察注射用丹参多酚酸(SAFI)对脑缺血大鼠急性期用药的可行性,明确大鼠脑缺血再灌注后脑血流的变化及其与远期运动功能恢复之间的相关性。方法 将Wistar大鼠随机分为假手术组、模型组及SAFI (21 mg·kg-1)组。SAFI组根据不同给药时机又分为3个亚组,分别是再灌后立即给药组(SAFI 0周)、再灌后1周给药组(SAFI 1周)、再灌后2周给药组(SAFI 2周),每组每天给药1次,连续ip 7 d,为保持一致性,其余时间均ip生理盐水,假手术组及模型组分别ip等量生理盐水。采用线栓法构建大鼠脑缺血再灌注模型,假手术组仅分离血管。通过观测大鼠一般状态、评估大鼠神经功能和脑梗死体积百分比考察SAFI急性期给药的药效作用;利用激光多普勒技术检测大鼠局部脑血流量(rCBF);通过转棒实验和步态实验分析大鼠的运动能力;通过Pearson相关性分析方法评估不同时间点的脑血流变化与远期运动功能恢复之间的相关性。结果 与模型组比较,SAFI 0周组大鼠的神经功能评分显著降低(P<0.01),脑梗死体积百分比显著降低(P<0.01),rCBF显著提升(P<0.05、0.01),死亡率明显下降;与模型组比较,SAFI 0周组大鼠在转棒仪上跌落潜伏期显著增加(P<0.05、0.01),SAFI 0周组大鼠在步态仪上运动速度显著增加(P<0.01),四肢的摆动时间、站立时间和步态周期显著下降(P<0.05、0.01),四肢(除左后肢外)的步幅显著增加(P<0.05、0.01)。与SAFI 1、2周组比较,SAFI 0周组脑梗死体积百分比显著降低(P<0.01),死亡率降低,rCBF显著升高(P<0.05、0.01),明显促进了神经行为学功能及运动功能的恢复。Pearson相关性分析结果表明脑缺血再灌注损伤后早期的脑血流恢复与远期运动功能呈线性相关。结论 SAFI在缺血急性期给药具有一定的可行性;脑缺血后梗死周边区域血流恢复对远期运动功能的恢复至关重要。  相似文献   
3.
《Pancreatology》2022,22(6):698-705
BackgroundThe functional and morphological recovery following an episode of acute pancreatitis (AP) in children still remains ill understood as research exploring this is limited. We aimed to characterize the morphological and functional changes in pancreas following AP and ARP (acute recurrent pancreatitis) in children.MethodsChildren with AP were followed prospectively and assessed at two time points at least 3 months apart, with the first assessment at least 3 months after the AP episode. Exocrine and endocrine functions were measured using fecal elastase and fasting blood sugar/HbA1c levels respectively. Morphological assessment was done using endoscopic ultrasound (EUS) and magnetic resonance imaging and cholangiopancreatography (MRI/MRCP).ResultsSeventy-three children (boys:59%; mean age:8.4 ± 3.2years) were studied and 21 of them (29%) progressed to ARP. Altered glucose homeostasis was seen in 19 (26%) at first and 16 (22%) at second assessment and it was significantly more in ARP group than the AP group at first (42.8%vs19.2%; p = 0.03) as well as second assessment (38.1%vs15.3%; p = 0.03). Twenty-one children (28.7%) at first and 24 (32.8%) at second assessment developed biochemical exocrine pancreatic insufficiency. EUS detected indeterminate and suggestive changes of chronic pancreatitis in 21% at first (n = 38) and 27.6% at second assessment (n = 58). On MRCP, main pancreatic duct and side branch dilatation were seen in 15 (20.5%) and 2 (2.7%) children respectively.ConclusionsMore than one-quarter of children have evidence of altered glucose homeostasis and biochemical exocrine pancreatic insufficiency following an episode of AP. Similarly, morphological features of chronicity seen in some of the children suggest that a fraction of subjects may develop chronic pancreatitis on longer follow-up.  相似文献   
4.
目的:观察压力支持通气模式(Pressure Support Ventilation,PSV)对重症监护患者睡眠质量的影响。方法:选取2017年1月至2017年8月德州市陵城区人民医院重症监护病房(ICU)收治的重症治疗患者60例作为研究对象,按照随机数字表法分为观察组和对照组,每组30例。对照组患者给予低剂量镇静加气管插管的方式进行干预,观察组患者给予压力支持通气模式进行干预,采用匹兹堡睡眠指数量表(Pittsburgh Sleep Quality Index,PSQI)比较2组患者干预前后的睡眠质量改善情况,采用抑郁自评量表(Self-rating Depression Scale,SDS)、焦虑自评量表(Self-rating Anxiety Scale,SAS)比较2组患者干预前后的焦虑以及抑郁状态改善情况。结果:干预后,观察组PSQI评分显著低于对照组,观察组SAS评分、SDS评分显著低于对照组,2组比较差异均有统计学意义(P<0.05)。结论:对重症监护患者采用压力支持通气模式有利于改善患者的睡眠质量。  相似文献   
5.
Numerous risk variables, including age, medical co-morbidities, and deranged inflammatory response, lead to higher mortality in a senior population with coronavirus disease 2019. C-reactive protein (CRP), an acute phase inflammatory protein secreted by the liver, was tested in the elderly, showing a diagnostic and prognostic role. However, recent research has shed light on new applications for CRP in geriatrics. It was used as a follow-up marker and as a therapeutic target. Early and accurate identification of patients' risks may mitigate the devastation of the invading virus in older cases and permit the implementation of a quick treatment plan for those most likely to deteriorate.  相似文献   
6.
AimThis review aims to summarize and discuss some of the most relevant clinical trials in epidemiology, diagnostics, and treatment of hypertension published in 2020 and 2021.Data synthesisThe trials included in this review are related to hypertension onset age and risk for future cardiovascular disease, reliability of different blood pressure monitoring methods, role of exercise-induced hypertension, treatment of hypertension in patients with SARS-CoV-2 infection, management of hypertension high-risk patient groups, e.g., in the elderly (≥80 years) and patients with atrial fibrillation, and the interplay between nutrition and hypertension, as well as recent insights into renal denervation for treatment of hypertension.ConclusionsHypertension onset age, nighttime blood pressure levels and a riser pattern are relevant for the prognosis of future cardiovascular diseases. The risk of coronary heart disease appears to increase linearly with increasing exercise systolic blood pressure. Renin-angiotensin system blockers are not associated with an increased risk for a severe course of COVID-19. In elderly patients, a risk-benefit assessment of intensified blood pressure control should be individually evaluated. A J-shaped association between cardiovascular disease and achieved blood pressure could also be demonstrated in patients with atrial fibrillation on anticoagulation. Salt restriction and lifestyle modification remain effective options in treating hypertensive patients at low cardiovascular risk. Sodium glucose co-transporter 2 inhibitors and Glucagon-like peptide-1 receptor agonists show BP-lowering effects. Renal denervation should be considered as an additional or alternative treatment option in selected patients with uncontrolled hypertension.  相似文献   
7.
BackgroundTherapeutic plasma exchange (TPE) is an extracorporeal treatment that can be used in adult and pediatric patients with acute demyelinating syndromes of the central nervous system. In this study, the efficacy and safety of TPE was evaluated in 10 pediatric patients who underwent TPE that were unresponsive to corticosteroid treatment.MethodsRecords of 10 pediatric patients who underwent TPE in our pediatric intensive care unit (PICU) between May 2017 and June 2020 were used. Expanded Disability Status Scale (EDSS), Gait Scale (GS), and Visual Outcome Scale (VOS) were applied to the patients before and after TPE.ResultsOf the 10 patients who underwent TPE, five were diagnosed with multiple sclerosis (MS), three with transverse myelitis (TM), and two with acute disseminated encephalomyelitis (ADEM). The median age of the patients was 13.3 years (IQR 8-15), and the median day from symptom onset to onset of TPE was 12.5 days (IQR 7-28). A total of 104 TPE sessions were performed successfully. While no complications were encountered in three patients during the sessions, the most common complication was hypofibrinogenemia. The decrease in EDSS and GS scores was found to be consistent with the clinical response of the patients. There was no statistically significant decrease in the VOS.ConclusionsWith this study, we can say that TPE is a feasible, effective, and safe treatment modality in children with acute demyelinating syndromes of the central nervous system.  相似文献   
8.
目的探讨中性粒细胞与淋巴细胞比值(NLR)、血清总胆红素(TBIL)和钠(Na)对急性阑尾炎严重程度的预测价值。方法选取2018年10月至2021年2月在皖西卫生职业学院附属医院住院并行阑尾切除术的271例急性阑尾炎患者为研究对象。根据术后病理诊断将患者分为单纯性阑尾炎组(228例)和复杂性阑尾炎组(43例),比较2组患者的临床资料和各项检测指标。采用多因素Logistic回归模型分析复杂性阑尾炎的危险因素,采用受试者工作特征(ROC)曲线分析NLR、血清TBIL和Na单独及联合检测对复杂性阑尾炎的预测价值。结果复杂性阑尾炎组的术前体温、白细胞计数、中性粒细胞计数、单核细胞与淋巴细胞比值、血小板与淋巴细胞比值、NLR及血清TBIL、直接胆红素、间接胆红素水平均高于单纯性阑尾炎组(P<0.05),而淋巴细胞计数和血清Na水平均低于单纯性阑尾炎组(P<0.05)。多因素Logistic回归模型分析显示,NLR、血清TBIL和Na是复杂性阑尾炎的独立危险因素(OR=1.225、0.487、1.296,P<0.05)。Pearson相关分析显示,急性阑尾炎患者NLR、血清TBIL水平均与血清Na呈负相关(r=-0.255、-0.207,P<0.05),NLR与血清TBIL无相关性(r=0.076,P>0.05)。ROC曲线分析显示,NLR+TBIL+Na联合检测预测复杂性阑尾炎的曲线下面积为0.954,高于TBIL、Na、NLR单独检测的0.777、0.789、0.799(P<0.05);NLR+TBIL+Na联合检测预测复杂性阑尾炎的特异度和灵敏度分别为82.50%和95.30%。结论NLR、TBIL和Na是复杂性阑尾炎的独立危险因素,三者联合检测对复杂性阑尾炎具有较好的预测价值。  相似文献   
9.
 目的 探讨锌指蛋白ZFP580在体外蛙皮素诱导的胰腺腺泡细胞炎性反应过程中通过内质网应激通路发挥作用的机制,为急性胰腺炎(acute pancreatitis, AP)发病机制提供新的认识。方法 用蛙皮素体外刺激AR42J细胞,模拟AP过程中胰腺腺泡细胞的炎性反应状态,用MTT法测定细胞活力以确定蛙皮素的最佳诱导时间;分别用RT-PCR和Western Blot检测细胞中内质网应激相关分子和ZFP580的mRNA和蛋白表达;应用IRE1抑制剂MKC-3946干预AR42J细胞,观察ZFP580表达变化;最后用慢病毒转染方法沉默ZFP580后,用Hochest33342染色和RT-PCT、Western Blot评价其对细胞凋亡-坏死的影响。结果 以蛙皮素刺激后诱导AR42J细胞发生内质网应激,ZFP580表达在刺激8 h后开始升高,呈时间依赖性上升;应用MKC-3946后,ZFP580的表达显著降低;沉默ZFP580后,XBP-1s表达下降,同时沉默ZFP580组的Chop表达量要显著高于对照组,而Caspase-3的表达显著低于普通AP组;Hochest染色观察发现沉默ZFP580组的坏死细胞比例要显著高于普通AP组。结论 ZFP580在胰腺腺泡细胞内质网应激信号通路中的位置可能位于IRE1与XBP-1s之间,其可能通过改善凋亡-坏死比例,对减轻AP炎性反应有一定作用。  相似文献   
10.
Continuous utero-placental circulation, and patent umbilical blood vessels ensure an uninterrupted transfer of oxygen and nutrients to the fetus as well as clearance of metabolic waste products. The onset of labour characterized by progressive and strong uterine contractions poses a threat to fetal oxygenation as a result of collapsing the spiral arterioles traversing the myometrium to supply the placental bed, and repetitive compression of the blood vessels within the umbilical cord. Human fetuses are equipped with compensatory mechanisms to cope with transient interruptions of blood supply during labour. The ability to compensate may be blunted in cases of poor fetal reserves, increased metabolic demand (macrosomia or maternal fever), and due to non-hypoxic pathways (e.g. chorioamniontis or fetal hypovolumia-hypotension syndrome). Intrapartum fetal surveillance involves prompt recognition of the features that signal the onset of fetal decompensation on the cardiotocograph (CTG) to ensure a timely intervention to avoid hypoxic-ischaemic encephalopathy (HIE) or perinatal deaths. This article summarises a ‘physiological approach’ to the interpretation of the CTG which, in places, conflicts with other current UK guidance.  相似文献   
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