全文获取类型
收费全文 | 844篇 |
免费 | 36篇 |
国内免费 | 26篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 15篇 |
妇产科学 | 15篇 |
基础医学 | 131篇 |
口腔科学 | 19篇 |
临床医学 | 100篇 |
内科学 | 229篇 |
皮肤病学 | 39篇 |
神经病学 | 30篇 |
特种医学 | 105篇 |
外科学 | 92篇 |
综合类 | 22篇 |
预防医学 | 29篇 |
眼科学 | 8篇 |
药学 | 47篇 |
中国医学 | 1篇 |
肿瘤学 | 18篇 |
出版年
2022年 | 11篇 |
2021年 | 12篇 |
2019年 | 8篇 |
2018年 | 7篇 |
2017年 | 7篇 |
2016年 | 10篇 |
2015年 | 17篇 |
2014年 | 12篇 |
2013年 | 19篇 |
2012年 | 32篇 |
2011年 | 37篇 |
2010年 | 29篇 |
2009年 | 35篇 |
2008年 | 38篇 |
2007年 | 33篇 |
2006年 | 67篇 |
2005年 | 36篇 |
2004年 | 33篇 |
2003年 | 22篇 |
2002年 | 22篇 |
2001年 | 17篇 |
2000年 | 12篇 |
1999年 | 14篇 |
1998年 | 16篇 |
1997年 | 7篇 |
1996年 | 21篇 |
1995年 | 18篇 |
1994年 | 19篇 |
1993年 | 7篇 |
1992年 | 12篇 |
1991年 | 10篇 |
1990年 | 13篇 |
1989年 | 20篇 |
1988年 | 18篇 |
1987年 | 17篇 |
1986年 | 17篇 |
1985年 | 18篇 |
1983年 | 8篇 |
1981年 | 9篇 |
1980年 | 8篇 |
1977年 | 5篇 |
1976年 | 8篇 |
1975年 | 5篇 |
1974年 | 7篇 |
1972年 | 8篇 |
1971年 | 14篇 |
1970年 | 12篇 |
1969年 | 7篇 |
1968年 | 10篇 |
1955年 | 6篇 |
排序方式: 共有906条查询结果,搜索用时 15 毫秒
41.
Refractory Pulmonary Edema and Upper Body Hypoxemia During Veno‐Arterial Extracorporeal Membrane Oxygenation—A Case for Atrial Septostomy 下载免费PDF全文
Amit Prasad Ali Ghodsizad Christoph Brehm Mark Kozak Michael Körner Aly El Banayosy Kai Singbartl 《Artificial organs》2018,42(6):664-669
Veno‐arterial extracorporeal membrane oxygenation (VA‐ECMO) provides mechanical circulatory support for patients with advanced cardiogenic shock, facilitating myocardial recovery and limiting multi‐organ failure. In patients with severely limited left ventricular ejection, peripheral VA‐ECMO can further increase left ventricular and left atrial pressures (LAP). Failure to decompress the left heart under these circumstances can result in pulmonary edema and upper body hypoxemia, that is, myocardial and cerebral ischemia. Atrial septostomy can decrease LAP in these situations. However, the effects of atrial septostomy on upper body oxygenation remain unknown. After IRB approval, we identified 9 out of 242 adult VA‐ECMO patients between January 2011 and June 2016 who also underwent atrial septostomy for refractory pulmonary edema/upper body hypoxemia. We analyzed LAP/pulmonary capillary wedge pressure (PCWP), right atrial pressures (RAPs), PaO2/FiO2 ratios (blood samples from right radial artery), intrathoracic volume status, and resolution of pulmonary edema before and up to 48 h after septostomy. There were no procedure‐related complications. Thirty‐day survival was 44%. LAP/PCWP decreased by approximately 40% immediately following septostomy and remained so for at least 24 h. PaO2/FiO2 ratios significantly increased from 0.49 (0.38–2.12) before to 5.35 (3.01–7.69) immediately after septostomy and continued so for 24 h, 6.6 (4.49–10.93). Radiographic measurements also indicated a significant improvement in thoracic intravascular volume status after atrial septostomy. Atrial septostomy reduces LAP and improves upper body oxygenation and intrathoracic vascular volume status in patients developing severe refractory pulmonary edema while undergoing peripheral VA‐ECMO. Atrial septostomy therefore appears safe and suitable to reduce the risk of upper body ischemia under these circumstances. 相似文献
42.
Accuracy of fetal echocardiography 总被引:6,自引:0,他引:6
The reliability of prenatal ultrasound (US) for the detection of structural heart defects was investigated in a consecutive population of patients referred for prenatal US. Twenty-eight of 49 fetuses (57%) shown to have one or more heart defects with physical examination or autopsy were found to have congenital heart disease with prenatal US. There were 66 cardiac defects in 49 fetuses, 33 of which were entirely or partly identified (50%). Defects correctly diagnosed included hypoplasia of either ventricle, common atrioventricular canal, tetralogy of Fallot, transposition of the great vessels, and Ebstein anomaly. Defects rarely diagnosed correctly included semilunar valve stenosis, total anomalous pulmonary venous drainage, coarctation of the aorta, pulmonic atresia, atrioseptal defect, and ventricular septal defect. Many types of heart defects can be diagnosed accurately with prenatal US in a general population of patients not at high risk for congenital heart disease. Some lesions, however, were difficult to detect. 相似文献
43.
Delayed hepatic CT scanning: increased confidence and improved detection of hepatic metastases 总被引:1,自引:0,他引:1
Bernardino ME; Erwin BC; Steinberg HV; Baumgartner BR; Torres WE; Gedgaudas- McClees RK 《Radiology》1986,159(1):71-74
Fifty oncologic patients with suspected hepatic metastases were prospectively evaluated by dynamic sequential hepatic computed tomography (DSHCT) and by delayed iodine hepatic computed tomography (DICT) scanning. DICT scanning was performed 4-6 hours following administration of 60 g of intravenous iodine. Both techniques were evaluated for lesion definition relative to the adjacent hepatic parenchyma and for numbers of metastases detected. Metastases were detected by both techniques in 26 patients. Fifteen patients (58%) had lesions better defined by DICT. DICT scanning detected more metastases in seven of these 15 patients. In eight patients (31%), there was no difference between the two techniques in numbers of masses detected or lesion definition. In three cases (11%), metastases were more confidently identified on the initial or DSHCT scan. DICT scanning, as described, is useful in defining and detecting hepatic metastases, especially where there is questionable hepatic involvement or better quantification of size is necessary. 相似文献
44.
Paramagnetic macrocyclic chelates show promise as magnetic resonance (MR) imaging contrast agents due to stability and relaxivity comparable to those of DTPA-type chelates. For the three copper and manganese macrocyclic complexes studied in aqueous solution, T1 and T2 relaxivities ranged from 0.14 to 5.88 mM-1sec-1 at 6.25 MHz. In rats, the intravenous administration of 16 mumol/kg of Mn(cyclam) caused the liver T1 relaxation rate to double at 15 minutes after injection. T1 measurements by pulsed MR imaging and manganese analyses on excised tissue showed that both relaxation rate (1/T1) and manganese content of liver and kidney increase linearly with the dosage of Mn(cyclam). The linear relationship between 1/T1 and manganese content can be considered an "in tissue" relaxivity plot for the agent. The resulting relaxivity is 54 mM-1sec-1 in liver, compared with 3.1 mM-1sec-1 in aqueous solution. Although this work is preliminary, the implication for medical MR imaging applications is that macrocyclic contrast agents can be effective at approximately one-tenth the current typical dose used for gadolinium DTPA. 相似文献
45.
46.
试论当代西方锻炼行为阶段理论 总被引:5,自引:0,他引:5
身体锻炼可以促进身心健康,这一结论早已为人们所了解,但仍旧有许多人不能充分地获得锻炼所带来的身心效益。有研究表明,在那些已经开始参加有组织的身体锻炼项目的个体中,有相当比例的人在6个月内中途退出。理解和促进与人们健康有关的身体活动和锻炼的一个重要方面是研究锻炼行为的理论。本文尝试对当代西方锻炼心理学领域内引人注目的阶段理论做一概括性介绍,并分析当前阶段理论研究的热点。1锻炼行为阶段理论近三十年来,人们运用了大量心理学理论来预测、解释和改变个体的身体活动及锻炼行为。这些理论可以被概括为两大类:(1)连续体理论… 相似文献
47.
48.
GHADA BEAINO BABAK KHOSHNOOD MONIQUE KAMINSKI VÉRONIQUE PIERRAT STÉPHANE MARRET JACQUELINE MATIS BERNARD LEDÉSERT GÉRARD THIRIEZ JEANNE FRESSON JEAN‐CHRISTOPHE ROZÉ VÉRONIQUE ZUPAN‐SIMUNEK CATHERINE ARNAUD ANTOINE BURGUET BÉATRICE LARROQUE GÉRARD BRÉART PIERRE‐YVES ANCEL for the EPIPAGE Study Group 《Developmental medicine and child neurology》2010,52(6):e119-e125
Aim The aim of this study was to assess the independent role of cerebral lesions on ultrasound scan, and several other neonatal and obstetric factors, as potential predictors of cerebral palsy (CP) in a large population‐based cohort of very preterm infants. Method As part of EPIPAGE, a population‐based prospective cohort study, perinatal data and outcome at 5 years of age were recorded for 1812 infants born before 33 weeks of gestation in nine regions of France in 1997. Results The study group comprised 942 males (52%) and 870 females with a mean gestational age of 30 weeks (SD 2wks; range 24–32wks) and a mean birthweight of 1367g (SD 393g; range 450–2645g). CP was diagnosed at 5 years of age in 159 infants (prevalence 9%; 95% confidence interval [CI] 7–10%), 97 males and 62 females, with a mean gestational age of 29 weeks (SD 2wks; range 24–32wks) and a mean birthweight of 1305g (SD 386g; range 500–2480g). Among this group, 67% walked without aid, 14% walked with aid, and 19% were unable to walk. Spastic, ataxic, and dyskinetic CP accounted for 89%, 7%, and 4% of cases respectively. The prevalence of CP was 61% among infants with cystic periventricular leukomalacia, 50% in infants with intraparenchymal haemorrhage, 8% in infants with grade I intraventricular haemorrhage, and 4% in infants without a detectable cerebral lesion. After controlling for cerebral lesions and obstetric and neonatal factors, only male sex (odds ratio [OR] 1.52; 95% CI 1.03–2.25) and preterm premature rupture of membranes or preterm labour (OR 1.72; 95% CI 0.95–3.14) were predictors of the development of CP in very preterm infants. Interpretation Cerebral lesions were the most important predictor of CP in very preterm infants. In addition, infant sex and preterm premature rupture of membranes or preterm labour were also independent predictors of CP. 相似文献
49.
This study examined associations among excessive exercise, eating disorders, and selected psychological characteristics in college women ( N = 586). Participants were recruited from university classes and administered the Obligatory Exercise Questionnaire, Eating Disorders Inventory--2, Bulimia Test-Revised, and other psychosocial measures. Results indicated that obligatory exercise is best viewed as multidimensional. These dimensions were used, through cluster analysis, to generate a typology of exercisers. One identified group clearly manifested eating disorder traits and behaviors, as well as signs of psychological disturbance. Another group who exercised with equal intensity but less emotional fixation showed the fewest signs of eating disorders and psychological distress. 相似文献
50.
NiX HouY KingBR TangX ReadMA SmithR NicholsonRC 《第二军医大学学报》2005,26(4):385-385
Placental CRH plays a major role in the mechanisms controlling human pregnancy and parturition. Understanding how placental CRH production is regulated is therefore of importance. Previously we have shown that placental expression of CRH peptide and mRNA are inhibited by estrogens, in contrast to the stimulatory effects of estrogen on hypothalamic CRH production. Our current study found that in placental cells cotransfected with a CRH promoter construct and an estrogen receptor-alpha expression vector results in a differential regulation whereby 17beta estradiol (E2) decreased and the putative pure estrogen antagonist, ICI 182780, 相似文献