全文获取类型
收费全文 | 20226篇 |
免费 | 922篇 |
国内免费 | 251篇 |
专业分类
耳鼻咽喉 | 104篇 |
儿科学 | 459篇 |
妇产科学 | 766篇 |
基础医学 | 1138篇 |
口腔科学 | 131篇 |
临床医学 | 6647篇 |
内科学 | 3015篇 |
皮肤病学 | 169篇 |
神经病学 | 1877篇 |
特种医学 | 1141篇 |
外科学 | 1233篇 |
综合类 | 2773篇 |
现状与发展 | 1篇 |
预防医学 | 509篇 |
眼科学 | 211篇 |
药学 | 823篇 |
6篇 | |
中国医学 | 210篇 |
肿瘤学 | 186篇 |
出版年
2024年 | 24篇 |
2023年 | 119篇 |
2022年 | 275篇 |
2021年 | 403篇 |
2020年 | 462篇 |
2019年 | 400篇 |
2018年 | 461篇 |
2017年 | 397篇 |
2016年 | 415篇 |
2015年 | 417篇 |
2014年 | 1015篇 |
2013年 | 1097篇 |
2012年 | 983篇 |
2011年 | 1125篇 |
2010年 | 998篇 |
2009年 | 1037篇 |
2008年 | 1083篇 |
2007年 | 1154篇 |
2006年 | 1171篇 |
2005年 | 1086篇 |
2004年 | 963篇 |
2003年 | 752篇 |
2002年 | 676篇 |
2001年 | 706篇 |
2000年 | 567篇 |
1999年 | 512篇 |
1998年 | 414篇 |
1997年 | 419篇 |
1996年 | 374篇 |
1995年 | 339篇 |
1994年 | 273篇 |
1993年 | 232篇 |
1992年 | 201篇 |
1991年 | 177篇 |
1990年 | 134篇 |
1989年 | 77篇 |
1988年 | 84篇 |
1987年 | 62篇 |
1986年 | 58篇 |
1985年 | 76篇 |
1984年 | 43篇 |
1983年 | 32篇 |
1982年 | 41篇 |
1981年 | 20篇 |
1980年 | 10篇 |
1979年 | 7篇 |
1978年 | 10篇 |
1977年 | 5篇 |
1976年 | 8篇 |
1974年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Aaron Pitzele Mohammad Rahimi Eric Armbrecht 《The journal of maternal-fetal & neonatal medicine》2015,28(15):1770-1773
Objective: To determine whether packed red blood cell (PRBC) transfusion affects post-prandial superior mesenteric artery blood flow velocities (SMA BFVs) in very-low birth weight (VLBW) neonates and if so, at what time point after transfusion restoration of previous SMA BFV patterns occurs.Design/Methods: VLBW pre-term neonates, older than 14 days and tolerating bolus enteral feedings administered every 3?h were enrolled in this prospective observational study. Pulsed Doppler ultrasound was used to measure pre- and post-prandial (at 45?min) time-averaged mean, peak and end diastolic velocities (TAMV, PSV, EDV) immediately before and after 15?ml/kg of PRBC transfusion was given over 3?h; patent ductus arteriosus (PDA) status was also evaluated. Subsequent pre- and post-prandial SMA BFVs were recorded 24 and 48?h after the transfusion.Results: Pre- and post-prandial measurements were obtained for 21 out of 25 enrolled infants. Post-prandial SMA BFVs were attenuated during the feedings immediately after transfusion; at 24 and 48?h after transfusion, changes in post-prandial SMA BFVs were similar to those measured prior to transfusion; the presence of the PDA did not affect results.Conclusions: PRBC transfusion blunted SMA BFV responses to feedings immediately after the transfusion with normalization observed 24?h post-transfusion. 相似文献
2.
Improvement in Tricuspid Annular Plane Systolic Excursion with Pulmonary Hypertension Therapy in Pediatric Patients 下载免费PDF全文
3.
Dynamic LVOT Obstruction and Aortic Stenosis in the Same Patient: A Case of Challenging Doppler Hemodynamics 下载免费PDF全文
Matthew W. Parker M.D. Francis J. Kiernan M.D. 《Echocardiography (Mount Kisco, N.Y.)》2015,32(6):1030-1032
We present a patient with both dynamic left ventricular outflow tract obstruction and valvular aortic stenosis. The aortic valve was calcified, and velocities and gradients measured by continuous‐wave Doppler met standard criteria for severe aortic stenosis. The increased subvalvular velocities invalidated assumptions of the simplified Bernoulli equation; correction using the longer form of the Bernoulli equation suggested a lower but still significant gradient. The complex shape of the subvalvular spectral Doppler envelope indicated supranormal systolic function and dynamic left ventricular outflow obstruction. Left heart catheterization with an end‐hole catheter was required to determine the subvalvular and valvular components of the obstruction. 相似文献
4.
Moises Rodriguez-Gonzalez Antonio Moruno Tirado Reza Hosseinpour Jose Santos de Soto 《Texas Heart Institute journal / from the Texas Heart Institute of St. Luke's Episcopal Hospital, Texas Children's Hospital》2015,42(4):350-356
Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital condition. It responds well to early diagnosis and treatment, but otherwise the prognosis is poor. We present our case series of 12 patients (mean age, 2 ± 2.58 yr; age range, 2 mo–8 yr), emphasizing the diagnostic process and discussing our surgical results. The diagnosis of ALCAPA should be suspected in infants who have dilated cardiomyopathy with electrocardiographic changes that suggest ischemia, and in older children who have isolated mitral regurgitation. When clinical suspicion is high, the results of 2-dimensional echocardiography combined with color-flow Doppler studies in expert hands can establish the diagnosis, thus avoiding angiography in critically ill infants. The treatment of choice in our patients was transfer and reimplantation of the left coronary artery onto the ascending aorta. There were 2 deaths: both were infants in extremis who underwent emergency surgery. An older child with severe ventricular dysfunction was given mechanical ventricular assistance and then heart transplantation. As of this report, all 10 survivors remained well and asymptomatic. 相似文献
5.
6.
7.
《Clinical neurophysiology》2020,131(1):213-224
ObjectiveSystematically review the abnormalities in event related potential (ERP) recorded in Rett Syndrome (RTT) patients and animals in search of translational biomarkers of deficits related to the particular neurophysiological processes of known genetic origin (MECP2 mutations).MethodsPubmed, ISI Web of Knowledge and BIORXIV were searched for the relevant articles according to PRISMA standards.ResultsERP components are generally delayed across all sensory modalities both in RTT patients and its animal model, while findings on ERPs amplitude strongly depend on stimulus properties and presentation rate. Studies on RTT animal models uncovered the abnormalities in the excitatory and inhibitory transmission as critical mechanisms underlying the ERPs changes, but showed that even similar ERP alterations in auditory and visual domains have a diverse neural basis. A range of novel approaches has been developed in animal studies bringing along the meaningful neurophysiological interpretation of ERP measures in RTT patients.ConclusionsWhile there is a clear evidence for sensory ERPs abnormalities in RTT, to further advance the field there is a need in a large-scale ERP studies with the functionally-relevant experimental paradigms.SignificanceThe review provides insights into domain-specific neural basis of the ERP abnormalities and promotes clinical application of the ERP measures as the non-invasive functional biomarkers of RTT pathophysiology. 相似文献
8.
《Journal of vascular and interventional radiology : JVIR》2020,31(4):635-643
PurposeThis study evaluated the factors affecting contralateral and ipsilateral recurrent deep vein thrombosis (DVT) after iliac vein stent placement in patients with iliac vein compression syndrome (IVCS).Materials and MethodsData from 130 patients (95 female patients) who underwent catheter-directed thrombolysis and stent placement for IVCS with left lower leg thrombosis at a single institution were retrospectively analyzed. Mean patient age was 69.0 ± 14.0 years old. Median follow-up was 14 months (range, 3–164 months). Anticoagulation therapy was prescribed for 6 months, followed by lifelong antiplatelet therapy. Multivariate logistic regression analysis was performed to evaluate the factors affecting the development of contralateral and ipsilateral recurrent DVT.ResultsSeven patients (5.4%) developed contralateral DVT (median, 26 months; range, 2–61 months), and 11 patients (8.5%) developed ipsilateral DVT (median, 1 month; range, 0–53 months). Stent location (odds ratio [OR], 11.564; 95% confidence interval [CI], 1.159–115.417) and in-stent thrombosis during follow-up (OR, 15.142; 95% CI, 1.406–163.119) were predictors of recurrent contralateral DVT. Thrombophilia (OR, 47.560; 95% CI, 2.369–954.711), remaining inferior vena cava filter (OR, 30.552; 95% CI, 3.495–267.122), and in-stent thrombosis during follow-up (OR, 82.057; 95% CI, 2.915–2309.848) were predictors of ipsilateral DVT.ConclusionsContralateral DVT occurs late and is associated with extension of the iliac vein stent to the inferior vena cava and in-stent thrombosis. Ipsilateral DVT occurs relatively early and is associated with thrombophilia, remaining inferior vena cava filter, and in-stent thrombosis. 相似文献
9.
10.
目的:探讨三维血流能量成像(3D-CPA)和彩色多普勒血流成像(CDFI)的临床应用价值。方法:对47例原发性肝癌的病灶进行二维、CDFI及3D-CPA的检查,比较CDFI及3D-CPA显示肿瘤瘤内或瘤周血流多普勒信号丰富程度及血管分布类型,并检测肿瘤的血流参数。结果:3D-CPA显示肿瘤血流分布丰富程度及血管分布类型与CDFI均有显著性差异(均P<0.05),CDFI均可探及肿瘤的搏动性动脉血流,其中,收缩期峰值血流速度(PSV)为43~157cm/s,阻力指数(RI)为0.49~0.82,大于0.65者45例。结论:3D-CPA结合彩色多普勒血流参数的检测可作为临床评价原发性肝癌血供及血管分布的常规检查方法。 相似文献