全文获取类型
收费全文 | 305篇 |
免费 | 27篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 9篇 |
妇产科学 | 8篇 |
基础医学 | 39篇 |
口腔科学 | 8篇 |
临床医学 | 29篇 |
内科学 | 90篇 |
皮肤病学 | 7篇 |
神经病学 | 26篇 |
特种医学 | 14篇 |
外科学 | 32篇 |
综合类 | 26篇 |
预防医学 | 8篇 |
眼科学 | 1篇 |
药学 | 24篇 |
肿瘤学 | 12篇 |
出版年
2021年 | 3篇 |
2020年 | 1篇 |
2018年 | 4篇 |
2017年 | 3篇 |
2016年 | 7篇 |
2015年 | 8篇 |
2014年 | 10篇 |
2013年 | 12篇 |
2012年 | 7篇 |
2011年 | 7篇 |
2010年 | 14篇 |
2009年 | 21篇 |
2008年 | 16篇 |
2007年 | 4篇 |
2006年 | 8篇 |
2005年 | 15篇 |
2004年 | 16篇 |
2003年 | 10篇 |
2002年 | 11篇 |
2001年 | 9篇 |
2000年 | 18篇 |
1999年 | 7篇 |
1998年 | 9篇 |
1997年 | 9篇 |
1996年 | 10篇 |
1995年 | 5篇 |
1994年 | 7篇 |
1993年 | 15篇 |
1992年 | 8篇 |
1991年 | 5篇 |
1990年 | 1篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1984年 | 5篇 |
1982年 | 1篇 |
1981年 | 7篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1975年 | 2篇 |
1974年 | 5篇 |
1972年 | 2篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有334条查询结果,搜索用时 31 毫秒
81.
Red blood cells (RBCs) can be cryopreserved with shelf life of 10 years. However, shelf life of deglycerolized RBCs in conventional open system is just 24 hours, resulting in sporadic use of Frozen RBC (FS-RBC). Recently Naval Blood Research Laboratory (NBRL) method using ACP 215 (ACPTM 215 Haemonetics Cell Processing System) has been introduced, where shelf life of deglycerolized RBC is 14 days. FS-RBC unit is prepared from single blood donation, which needs to be glycerolized and deglycerolized. NBRL method using ACP 215 in FS-RBC is described. Deglycerolized unit weighed between 325–350 gm with haemoglobin of 15–18 gm/dl and freeze- thaw- wash RBC recovery of 87%. Transfusion of deglycerolized RBC offered advantages such as elimination of need of crossmatching in emergent situations and reduction of transfusion reactions. FS-RBC by NBRL method using ACP 215 has advantages such as long shelf life, meeting unexpected high blood demand in mass casualties situations or availability of rare blood group requirement of individual patient. FS-RBC can be a potential candidate for Indian Armed Forces Blood programme for uninterrupted blood supply during peace and war. 相似文献
82.
83.
Objective:To provide information on twin births and associated factors in Port barcourt South South Nigeria.Methods:Data on twin deliveries from 1st January 2003 to 31st December 2008 were collected and analysed.This included the maternal age and parity,gestation age,Apqar scores,sex and birth weight of twins.Results:A total of 11042 deliveries occurred over the study period with 333 being twins giving a twin rate of 1∶33.Male twins constituted 48% of twin births with male to female ratio of 1∶1.08.The mean age and parity of mothers were 29.6 years and 2.5 respectively.Presentation of the cephalic/cephalic for the first and second twins was the most common(63.4%).Severe birth asphyxia(first minute Apgar score 1-3)occurred in 3.9% of twins.Male-male twin pair occurred in 28.5% of twins,male-female in 39% while female-female occurred in 32.5%.The Caesarian section rate was 48%.Conclusion:The twining rate in this study is high.In this locality,there is a need for early ultrasound scanning of pregnant women particularly those of parities 1 to 3 and those aged 25-34 years in whom highest rates of twinning occurred to detect twinning when present and refer them to sufficiently equipped centres for adequate antenatal and perinatal care. 相似文献
84.
Duncan RC Spalding Kasim A Behranwala Peter Straker Jeremy N Thompson Robin CN Williamson 《Annals of the Royal College of Surgeons of England》2009,91(6):477-482
INTRODUCTION
Non-occlusive small bowel necrosis (NOSBN) has been associated with early postoperative enteral feeding. The purpose of this study was to determine the incidence of this complication in an elective upper gastrointestinal (GI) surgical patient population and the influence of both patient selection and type of feeding jejunostomy (FJ) inserted, based on the experience of two surgical units in affiliated hospitals.PATIENTS AND METHODS
The records were reviewed of 524 consecutive patients who underwent elective upper GI operations with insertion of a FJ for benign or malignant disease between 1997 and 2006. One unit routinely inserted needle catheter jejunostomies (NCJ), whilst the other selectively inserted tube jejunostomies (TJ).RESULTS
Six cases of NOSBN were identified over 120 months in 524 patients (1.15%), with no difference in incidence between routine NCJ (n = 5; 1.16%) and selective TJ (n = 1; 1.06%). Median rate of feeding at time of diagnosis was 105 ml/h (range, 75–125 ml/h), and diagnosis was made at a median of 6 days (range, 4–18 days) postoperatively. All patients developed abdominal distension, hypotension and tachycardia in the 24 h before re-exploratory laparotomy. Five patients died and one patient survived.CONCLUSIONS
The understanding of the pathophysiology of NOSBN is still rudimentary; nevertheless, its 1% incidence in the present study does call into question its routine postoperative use especially in those at high risk with an open abdomen, planned repeat laparotomies or marked bowel oedema. Patients should be fully resuscitated before initiating any enteral feeding, and feeding should be interrupted if there is any evidence of feed intolerance. 相似文献85.
Ellis K Wazni O Marrouche N Martin D Gillinov M McCarthy P Saad EB Bhargava M Schweikert R Saliba W Bash D Rossillo A Erciyes D Tchou P Natale A 《Journal of cardiovascular electrophysiology》2007,18(8):799-802
Introduction: Atrial fibrillation and atrial flutter often coexist. The long-term occurrence of atrial fibrillation in patients presenting with atrial flutter alone is unknown. We report the long-term follow-up in patients who underwent cavotricuspid isthmus ablation for treatment of lone atrial flutter.
Methods and Results: Between January 1997 and June 2002, 632 patients underwent cavotricuspid isthmus ablation for the treatment of typical atrial flutter at the Cleveland Clinic Foundation. Three hundred sixty-three patients were included in this study and followed for a mean duration of 39 ± 11 months. The mean duration of atrial flutter symptoms was 12 ± 5 months. Mean left-atrial size and left-ventricular ejection fraction were 4.2 ± 0.8 cm and 47 ± 13%, respectively. After a mean follow-up time of 39 ± 11 months, 13% (48 of 363) of the patients remained in sinus rhythm. Five percent (18 of 363) of patients experienced recurrence of atrial flutter only. Sixty-eight percent (246 of 363) experienced the onset of atrial fibrillation and 14% (51 of 363) experienced recurrence of atrial flutter and the new onset of atrial fibrillation. Overall, 82% (297 of 363) of the patients experienced new onset of drug refractory atrial fibrillation. Left-atrial size was a predictor of atrial fibrillation recurrence post-atrial flutter ablation.
Conclusion: At long-term follow-up, approximately 82% of patients post-cavotricuspid isthmus ablation for atrial flutter developed drug refractory atrial fibrillation. This finding suggests that elimination of atrial flutter might delay, but does not prevent, atrial fibrillation. Evidence suggests both arrhythmias may share common triggers and such patients may derive a better long-term benefit from anatomical ablative treatment of atrial fibrillation as well. 相似文献
Methods and Results: Between January 1997 and June 2002, 632 patients underwent cavotricuspid isthmus ablation for the treatment of typical atrial flutter at the Cleveland Clinic Foundation. Three hundred sixty-three patients were included in this study and followed for a mean duration of 39 ± 11 months. The mean duration of atrial flutter symptoms was 12 ± 5 months. Mean left-atrial size and left-ventricular ejection fraction were 4.2 ± 0.8 cm and 47 ± 13%, respectively. After a mean follow-up time of 39 ± 11 months, 13% (48 of 363) of the patients remained in sinus rhythm. Five percent (18 of 363) of patients experienced recurrence of atrial flutter only. Sixty-eight percent (246 of 363) experienced the onset of atrial fibrillation and 14% (51 of 363) experienced recurrence of atrial flutter and the new onset of atrial fibrillation. Overall, 82% (297 of 363) of the patients experienced new onset of drug refractory atrial fibrillation. Left-atrial size was a predictor of atrial fibrillation recurrence post-atrial flutter ablation.
Conclusion: At long-term follow-up, approximately 82% of patients post-cavotricuspid isthmus ablation for atrial flutter developed drug refractory atrial fibrillation. This finding suggests that elimination of atrial flutter might delay, but does not prevent, atrial fibrillation. Evidence suggests both arrhythmias may share common triggers and such patients may derive a better long-term benefit from anatomical ablative treatment of atrial fibrillation as well. 相似文献
86.
87.
CN Storrs 《Archives of disease in childhood》1977,52(7):534-540
Cardiovascular reflex responses have been studied in 9 newborn preterm infants with apnoeic episodes and in 2 preterm infants with periodic breathing. Respiration, blood pressure, heart rate, and peripheral blood flow were simultaneously recorded. Peripheral blood flow was measured in the leg by venous occlusion plethysmography. During apnoea, bradycardia and peripheral vasoconstriction occur. There is little change in blood pressure though pulse pressure increases. No cardiovascular changes were seen before the onset of apnoea. Periodic breathing had little effect on peripheral blood flow. Preterm infants with gestations as low as 27 weeks apparently have well developed chemoreceptor reflexes which would tend to preserve blood supply to the brain during conditions of hypoxia. 相似文献
88.
Acute methotrexate neurotoxicity: findings on diffusion-weighted imaging and correlation with clinical outcome 总被引:8,自引:0,他引:8
BACKGROUND AND PURPOSE: Acute lymphocytic leukemia (ALL) is a common malignancy of childhood treated with methotrexate (MTX), which is associated with acute neurotoxicity. We evaluated diffusion-weighted (DW) and conventional MR images in children with ALL and acute MTX-induced neurotoxicity, with clinical correlation. METHODS: Five patients aged 12-15 years underwent fluid-attenuated inversion recovery (FLAIR), T2-weighted fast spin-echo and gradient-echo, T1-weighted gadolinium-enhanced spin-echo, and DW imaging within 24 hours of symptom onset. Records were reviewed for the temporal relationship to MTX administration, strokelike symptoms, and neurologic outcome. RESULTS: Six strokelike events were temporally related to intrathecal MTX given 6-11 days before symptom onset. FLAIR images showed abnormal hyperintensity in the callosal splenium in one patient but were otherwise normal. Diffusion abnormalities were frontoparietal in three events and frontal in one; nonfluent aphasia was seen in all. Bilateral frontoparietal diffusion abnormalities were associated with bilateral upper-extremity weakness, right-sided hemiparesis, or left-sided hemiparesis (one patient each); one patient had mild facial droop. Unilateral precentral subcortical diffusion abnormality was associated with contralateral motor deficit and ipsilateral upper-extremity sensory loss. Strokelike symptoms resolved rapidly and were not associated with other signs of encephalopathy. Subsequent intrathecal MTX administration was not associated with recurrence in four patients. CONCLUSION: Diffusion abnormalities in acute MTX neurotoxicity indicated cerebral dysfunction but not necessarily overt structural injury to the cerebrum. Subsequent demyelination or gliosis could not be predicted on the basis of diffusion abnormalities. A single strokelike episode with diffusion abnormalities should not necessarily prompt modification of potentially curative chemotherapeutic regimens. 相似文献
89.
Intracranial vascular stenosis and occlusive disease: evaluation with CT angiography, MR angiography, and digital subtraction angiography 总被引:16,自引:0,他引:16
Bash S Villablanca JP Jahan R Duckwiler G Tillis M Kidwell C Saver J Sayre J 《AJNR. American journal of neuroradiology》2005,26(5):1012-1021
BACKGROUND AND PURPOSE: Although digital subtraction angiography (DSA) provides excellent visualization of the intracranial vasculature, it has several limitations. Our purpose was to evaluate the ability of helical CT angiography (CTA) to help detect and quantify intracranial stenosis and occlusion compared with DSA and MR angiography (MRA). METHODS: Twenty-eight patients underwent CTA, DSA, and 3D time-of-flight (TOF) MRA for suspected cerebrovascular lesions. All three studies were performed within a 30-day period. Two readers blinded to prior estimated or calculated stenoses, patient history and clinical information examined 672 vessel segments. Lesions were categorized as normal (0-9%), mild (10-29%), moderate (30-69%), severe (70-99%), or occluded (no flow detected). DSA was the reference standard. Unblinded consensus readings were obtained for all discrepancies. RESULTS: A total of 115 diseased vessel segments were identified. After consensus interpretation, CTA revealed higher sensitivity than that of MRA for intracranial stenosis (98% versus 70%, P < .001) and occlusion (100% versus 87%, P = .02). CTA had a higher positive predictive value than that of MRA for both stenosis (93% versus 65%, P < .001) and occlusion (100% versus 59%, P < .001). CTA had a high interoperator reliability. In 6 of 28 patients (21%), all 6 with low-flow states in the posterior circulation, CTA was superior to DSA in detection of vessel patency. CONCLUSION: CTA has a higher sensitivity and positive predictive value than MRA and is recommended over TOF MRA for detection of intracranial stenosis and occlusion. CTA has a high interoperator reliability. CTA is superior to DSA in the evaluation of posterior circulation steno-occlusive disease when slow flow is present. CTA results had a significant effect on patient clinical management. 相似文献
90.
OBJECTIVE: To determine the effect of IV methylprednisolone (IVMP) on brain fraction volume (BFV), contrast-enhancing (CE) lesions, and white matter lesion load (WMLL) in patients with relapsing-remitting MS treated for acute exacerbations. BACKGROUND: MRI metrics of MS disease activity are being used as outcome measures in early phase treatment trials, however the short-term effects of IVMP treatment on cerebral atrophy are unknown. METHODS: Serial monthly MRI were performed in 26 patients enrolled in a baseline vs treatment trial with interferon beta-1b (IFNbeta-1b) who were followed for 3 months before and after IVMP. All 26 patients were evaluated while receiving IFNbeta-1b, and 12 patients were also studied during the baseline stage of the trial (NHx). Acute exacerbations were treated with IVMP (1 g/d) for 3 to 5 days. Precontrast and postcontrast T1-weighted and proton density T2-weighted fast spin-echo images were analyzed. RESULTS: Fifty-six acute exacerbations were evaluated. For the 3 months before IVMP, there was no difference in WMLL or BFV compared to month IVMP was administered. There was a significant decrease in BFV at month 1 after IVMP in the IFNbeta-1b and NHx groups. Compared to the month IVMP was administered, there was a difference in the CE lesions for months -3 and -1 prior (p < 0.039) in NHx patients. Following IVMP, CE lesions decreased (p < 0.0004) for months 1, 2, and 3 in both groups, but there was no effect on WMLL. CONCLUSIONS: BFV and CE lesions were significantly decreased for 1 month (BFV) and 3 months (CE lesions) following IVMP. Therefore, MRI studies should be delayed by probably at least 2 months following IVMP to avoid a possible confounding steroid effect in a clinical trial. 相似文献