全文获取类型
收费全文 | 1181篇 |
免费 | 81篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 85篇 |
妇产科学 | 8篇 |
基础医学 | 99篇 |
口腔科学 | 27篇 |
临床医学 | 76篇 |
内科学 | 205篇 |
皮肤病学 | 27篇 |
神经病学 | 27篇 |
特种医学 | 136篇 |
外科学 | 129篇 |
综合类 | 135篇 |
预防医学 | 78篇 |
眼科学 | 8篇 |
药学 | 57篇 |
中国医学 | 39篇 |
肿瘤学 | 141篇 |
出版年
2023年 | 8篇 |
2022年 | 16篇 |
2021年 | 26篇 |
2020年 | 20篇 |
2019年 | 16篇 |
2018年 | 21篇 |
2017年 | 14篇 |
2016年 | 21篇 |
2015年 | 31篇 |
2014年 | 44篇 |
2013年 | 41篇 |
2012年 | 58篇 |
2011年 | 49篇 |
2010年 | 75篇 |
2009年 | 61篇 |
2008年 | 27篇 |
2007年 | 32篇 |
2006年 | 45篇 |
2005年 | 34篇 |
2004年 | 24篇 |
2003年 | 26篇 |
2002年 | 12篇 |
2001年 | 17篇 |
2000年 | 15篇 |
1999年 | 26篇 |
1998年 | 50篇 |
1997年 | 60篇 |
1996年 | 52篇 |
1995年 | 44篇 |
1994年 | 37篇 |
1993年 | 36篇 |
1992年 | 16篇 |
1991年 | 11篇 |
1990年 | 14篇 |
1989年 | 30篇 |
1988年 | 22篇 |
1987年 | 20篇 |
1986年 | 17篇 |
1985年 | 11篇 |
1984年 | 11篇 |
1982年 | 11篇 |
1981年 | 9篇 |
1980年 | 13篇 |
1977年 | 7篇 |
1976年 | 8篇 |
1975年 | 4篇 |
1973年 | 3篇 |
1972年 | 4篇 |
1971年 | 3篇 |
1958年 | 4篇 |
排序方式: 共有1280条查询结果,搜索用时 31 毫秒
61.
62.
A Ohlsson SA Calvert M Hosking AT Shennan 《Acta paediatrica (Oslo, Norway : 1992)》1992,81(10):751-756
This randomized controlled trial was designed to answer the question: does administration of dexamethasone to neonates with bronchopulmonary dysplasia decrease the need for assisted ventilation? Twenty-five infants with a birth weight < 1501 g, requiring mechanical ventilation and FiO2 of ± 0.30 at 21-35 days of age, were randomized to treatment with iv dexamethasone or to sham injections for 12 days. The primary outcome criterion was extubation within seven days after study entry. Treatment (n= 12) and control (n= 13) groups were well matched at entry. Dexamethasone facilitated weaning from assisted ventilation (p= 0.0154). There was no increased incidence of infection. Dexamethasone treatment resulted in a significant increase in glucosuria (p= 0.0002) and in systolic blood pressure (p= 0.0034). There was a significant decrease in heart rate (p= 0.0001) and a significant weight loss (p= 0.0002) following dexamethasone treatment. Dexamethasone treatment facilitated weaning from assisted ventilation but several systemic effects were noted that deserve further evaluation before dexamethasone becomes routine treatment. 相似文献
63.
Effects of positive and negative pressure ventilation on cerebral blood volume of newborn infants 总被引:3,自引:0,他引:3
KS Palmer SA Spencer YABD Wickramasinghe T Wright DP Southall P Rolfe 《Acta paediatrica (Oslo, Norway : 1992)》1995,84(2):132-139
The effects of intermittent positive airway and continuous negative extrathoracic pressure ventilation on cerebral blood volume in preterm infants were studied using near infrared spectroscopy. In 12 infants continuous negative extrathoracic pressure caused a median decrease in cerebral blood volume of 0.14ml/100ml brain (95% confidence intervals (CI) 0.035–0.280) compared with no respiratory support. Oxygenated and deoxygenated haemoglobin also decreased, implying increased venous drainage as the main effect. In 17 infants intermittent positive pressure ventilation also caused a median reduction in cerebral blood volume of 0.06 ml/100 ml brain (95% CI 0.010–0.115) compared with endotracheal positive airway pressure. Deoxygenated haemoglobin increased by 0.07 ml/100 ml brain (95% CI 0.010–0.100) while oxygenated haemoglobin decreased by O.lOml/lOOml brain (95% CI 0.005–0.175). The increase in deoxygenated haemoglobin implies decreased venous drainage and the decrease in oxygenated haemoglobin implies that other factors may also be significant. Heart rate, blood pressure and oxygen saturation were monitored continuously and remained stable. 相似文献
64.
目的:通过对突发性聋病人血中一氧化氮(NO)、丙二醛(MDA)、超氧化物歧化酶(SOD)含量的检洲,探讨突聋与血氧自由基和自由基的清除剂SOD之间的关系。方法:采用硝酸还原酶法测定了30例突聋病人血中NO含量,并以25例同期体检正常的健康人为对照组;同时还用硫代巴比妥酸比色法测定MDA含量,用黄嘌呤氧化酶法测定SOD含量。砖呆;应用金纳多、能量合剂、克林臭(即马来酸桂哌齐特,钙通道阻滞药)联合静脉输入,突聋各组的听力均有不同程度提高,有效率在78.57%以上。治疗后同对照组相比,血清NO、MDA水平明显低于患病之初,而SOD活性明显高于治疗之前,P〈0.01。结论;检测突聋病人血中N0、MDA、SOD的含量,能帮助我们探讨突聋的发病机理,估计预后。血氧自由基的升高可能是突聋发病因素之一,而SOD的含量可以帮助我们估计预后。 相似文献
65.
F Haque ST Fazal SA Ahmad SZ Abbas S Naseem 《Journal of Medical Imaging and Radiation Oncology》2006,50(1):63-65
Primary osteogenic sarcoma of the skull is an exceedingly rare condition. An adult male patient is described, who had a painless swelling in the right forehead that had rapidly enlarged in the previous 6 months. Radiological investigations showed a large destructive mass lesion involving the right side of the frontal bone with extension into the frontal sinus, causing marked extradural compression of brain parenchyma. Histopathological examination confirmed the lesion to be primary osteogenic sarcoma. 相似文献
66.
维甲酸和联合应用神经营养因子对新生大鼠神经干细胞分化的影响 总被引:1,自引:0,他引:1
目的研究全反式维甲酸(ATRA)及联合应用神经营养因子(BDNF,GDNF)对体外培养的神经干细胞(NSCs)分化的影响。方法取新生SD大鼠的前脑室下带(SVZ)区,按NSCs的常规培养方法分离、培养。用免疫细胞化学法鉴定巢蛋白(nestin)、微管相关蛋白-2(MAP-2)、胶质原纤维酸性蛋白(GFAP)的表达,以此来观察ATRA、BDNF、GDNF单独或联合应用对次代神经球细胞分化的作用。结果原代及次代神经球均显示nestin阳性,并可分化为MAP-2阳性神经元样细胞及GFAP阳性胶质细胞样细胞。1μmol/LATRA可促进NSCs分化为MAP-2阳性细胞的比例达(29.14±5.00)%,显著高于对照组的(7.19±1.21)%,差异有高度统计学意义(P〈0.001)。ATRA联合应用10ng/ml的BDNF或GDNF,与单独使用ATRA比较,并不显著提高NSCs分化为MAP-2阳性细胞的比例。结论ATRA可促进神经干细胞向神经元方向分化,ATRA联合应用BDNF或GDNF无明显的协同作用。 相似文献
67.
Relations between age, metabolic control, disease adjustment and psychological aspects in insulin-dependent diabetes mellitus 总被引:1,自引:0,他引:1
B Lernmark G Dahlqvist P Fransson B Hägglöf SA Ivarsson J Ludvigsson S Sjöblad G Thernlund 《Acta paediatrica (Oslo, Norway : 1992)》1996,85(7):818-824
The relations between age, metabolic control, disease adjustment, and psychological factors in boys and girls with recently diagnosed insulin-dependent diabetes mellitus (IDDM) were studied. Older girls had significant higher postremission glycosylated haemoglobin A (Hb Alc ) levels ( p = 0.008). Girls with more hospitalizations had a lower developmental level ( p = 0.05), and had significantly more problems in the behavioural rating ( p = 0.05). Boys with more hospitalizations had a more external locus of control ( p = 0.01), more difficulties with disease adjustment, more emotional problems, and were also clinically assessed as having more behavioural problems. Boys showing more difficulties in psychological adjustment to the disease also had higher postremission Hb A1c levels ( p = 0.02). Although Swedish children with IDDM of short disease duration do not differ from healthy children in important psychological aspects, older girls and a small group of problematic younger boys are at risk of developing metabolic imbalance after a short disease duration. 相似文献
68.
JW Gregory SA Greene RT Jung CM Scrimgeour MJ Rennie 《Archives of disease in childhood》1993,68(2):205-209
Fourteen children receiving one year of recombinant human growth hormone (rhGH) treatment underwent measurement of serial changes in body composition (measured by skinfold thickness, bioelectrical impedance, and H2(18)O dilution), resting energy expenditure (REE, estimated by ventilated hood indirect calorimetry), and total free living daily energy expenditure (TEE, measured by the doubly labelled water technique). Mean height velocity increased from 4.9 to 8.6 cm/year after six months of treatment. Fat free mass (FFM) increased more during the first six weeks (24.4 g/day) than from six to 26 weeks of treatment (6.8 g/day); fat mass decreased by 7.2 g/day and 1.1 g/day respectively. The six week increase in REE (kJ/day) was maintained after six months of treatment, though expressed per kilogram FFM (kJ/kgFFM/day), returned to pretreatment values by three months. Height velocity increases at six months correlated with six week changes in fat mass measured by skinfold thickness and REE, though use of this relationship to predict growth response in individuals is limited by the wide 95% prediction intervals. No significant changes in growth, body composition, or energy expenditure were observed between six and 12 months of treatment, in either patients who had initially responded well to treatment or those who were poor initial responders to treatment and who had their dose of rhGH doubled after six months. 相似文献
69.
Fuqua SA Wiltschke C Zhang QX Borg A Castles CG Friedrichs WE Hopp T Hilsenbeck S Mohsin S O'Connell P Allred DC 《Cancer research》2000,60(15):4026-4029
The best current model of breast cancer evolution suggests that most cancers arise from certain premalignant lesions. We have identified a common (34%) somatic mutation in the estrogen receptor (ER)-alpha gene in a series of 59 typical hyperplasias, a type of early premalignant breast lesion. The mutation, which affects the border of the hinge and hormone binding domains of ER-alpha, showed increased sensitivity to estrogen as compared with wild-type ER-alpha in stably transfected breast cancer cells, including markedly increased proliferation at subphysiological levels of estrogen. The mutated ER-alpha exhibits enhanced binding to the TIF-2 coactivator at low levels of hormone, which may partially explain its increased estrogen responsiveness. These data suggest that this mutation may promote or accelerate the development of cancer from premalignant breast lesions. 相似文献
70.