全文获取类型
收费全文 | 2074篇 |
免费 | 18篇 |
国内免费 | 8篇 |
专业分类
儿科学 | 22篇 |
妇产科学 | 8篇 |
基础医学 | 111篇 |
临床医学 | 156篇 |
内科学 | 58篇 |
皮肤病学 | 5篇 |
神经病学 | 245篇 |
特种医学 | 21篇 |
外科学 | 75篇 |
综合类 | 372篇 |
预防医学 | 81篇 |
药学 | 912篇 |
2篇 | |
中国医学 | 30篇 |
肿瘤学 | 2篇 |
出版年
2022年 | 14篇 |
2021年 | 8篇 |
2020年 | 12篇 |
2019年 | 22篇 |
2018年 | 18篇 |
2017年 | 22篇 |
2016年 | 16篇 |
2015年 | 31篇 |
2014年 | 76篇 |
2013年 | 75篇 |
2012年 | 79篇 |
2011年 | 96篇 |
2010年 | 85篇 |
2009年 | 81篇 |
2008年 | 74篇 |
2007年 | 75篇 |
2006年 | 85篇 |
2005年 | 75篇 |
2004年 | 68篇 |
2003年 | 56篇 |
2002年 | 40篇 |
2001年 | 41篇 |
2000年 | 34篇 |
1999年 | 35篇 |
1998年 | 21篇 |
1997年 | 30篇 |
1996年 | 22篇 |
1995年 | 34篇 |
1994年 | 30篇 |
1993年 | 24篇 |
1992年 | 28篇 |
1991年 | 38篇 |
1990年 | 32篇 |
1989年 | 24篇 |
1988年 | 34篇 |
1987年 | 34篇 |
1986年 | 31篇 |
1985年 | 54篇 |
1984年 | 63篇 |
1983年 | 43篇 |
1982年 | 66篇 |
1981年 | 66篇 |
1980年 | 51篇 |
1979年 | 47篇 |
1978年 | 29篇 |
1977年 | 24篇 |
1976年 | 19篇 |
1975年 | 10篇 |
1974年 | 11篇 |
1973年 | 6篇 |
排序方式: 共有2100条查询结果,搜索用时 15 毫秒
1.
Canada continues to experience an escalating opioid overdose crisis that has claimed more than 8000 lives in the country since 2016. The presence of the synthetic opioid fentanyl and its analogues is a central contributor to the increases in preventable opioid-related deaths. However, a number of converging social-structural factors (e.g., the continued criminalisation of drug use, political changes) and political barriers are also complicating and contributing to the current crisis. We briefly outline four harm reduction interventions (i.e., injectable opioid agonist treatment, naloxone distribution programs, overdose prevention sites, and drug checking services) as emerging and rapidly expanding responses to this crisis in Canada. These examples of innovation and expansion are encouraging but also occurring at the same time that the opioid overdose crisis shows few signs of abating. To truly address the crisis, Canada needs political environments at all government levels that are responsive and foster harm reduction innovation and drug policy experimentation. 相似文献
2.
Acupuncture analgesia (AA) caused by low frequency stimulation of the acupuncture point (AP) was abolished by hypophysectomy and adrenalectomy. Termination of the AA producing pathway from the AP to the pituitary gland was in the medial hypothalamic arcuate nucleus (M-HARN). The origin of the descending pain inhibitory system associated with AA was in the posterior HARN (P-HARN). AA in the hypophysectomized rats, and enhanced neuronal activity in the P-HARN that were abolished during acupuncture stimulation, were both restored by intraperitoneal microinjection of 0.5 mg/kg morphine or 0.1 micrograms beta-endorphin into the P-HARN during acupuncture stimulation. Of the analgesia produced by dopamine or beta-endorphin injected into the P-HARN, that caused by beta-endorphin disappeared after denervation of the M-HARN. The P-HARN neurons that responded to acupuncture stimulation also responded to iontophoretic dopamine, but not to iontophoretic morphine nor ultramicroinjected beta-endorphin. The transmission between the M-HARN and P-HARN may be dopaminergic, and beta-endorphin might presynaptically modulate this transmission. Reduction of sodium ions may have been the reason for abolition of AA after adrenalectomy. 相似文献
3.
氨茶碱伍用纳洛酮治疗早产儿原发性呼吸暂停疗效观察(附46例临床报告) 总被引:3,自引:0,他引:3
目的观察氨茶碱伍用纳洛酮治疗早产儿原发性呼吸暂停的临床疗效。方法将112例早产儿随机分为两组,对照组(66例)和观察组(46例),对照组及观察组均应用氨茶碱治疗呼吸暂停,观察组加用纳洛酮,首次按0.1mg/kg静脉侧入,继之以0.1mg/kg,以0.03~0.05mg/(kg·h)速度静脉泵入,连用3d。比较两组原发性呼吸暂停的时间和发生次数、心率、经皮血氧饱和度等的差异。结果两组呼吸暂停次数为(1.6±0.9)次/dvs(3.0±1.7)次/d及日均积分(1.7±1.3)分vs(3.6±2.4)分,观察组均明显减少,P<0.001和P<0.05;呼吸暂停的时间(18.6±3.5)svs(20.2±3.9)s,观察组明显缩短;SpO2(81.0±10.6)%vs(75.4±8.9)%及心率(91.2±12.6)次/minvs(84.6±14.3)次/min,观察组下降程度明显减轻(P<0.05)。治疗组总有效率明显优于对照组(χ2=8.47,P<0.01)。结论氨茶碱伍用纳洛酮治疗早产儿原发性呼吸暂停疗效显著。 相似文献
4.
Naloxone administration following operant training of sucrose/water discrimination in the rat 总被引:2,自引:0,他引:2
E. O’Hare J. Cleary D. T. Weldon C. J. Billington A. S. Levine P. J. Bartz 《Psychopharmacology》1997,129(3):289-294
The suppression of food intake observed following naloxone administration has often been ascribed to palatability or taste.
Unfortunately, many confounds become apparent when attempts are made to isolate such factors in the investigation of ingestive
behaviors. In the present study, rats (two groups) were trained to discriminate either a 10% or 5% sucrose solution from water
(0.1 ml). These mildly food deprived subjects (95% of free-feeding weight) were trained to press the appropriate lever in
a two-lever operant chamber following sampling of sucrose or water; successful responding was reinforced by delivery of a
45 mg grain food pellet. Following random exposure to reduced sucrose concentrations tested under extinction, a sucrose concentration
gradient (1.0, 0.5, 0.1, 0.05, 0.01 and 0.005% sucrose solution) was established for both training groups under IP saline
administration. Data collected under IP saline were then compared to those collected following random IP naloxone administration
(3.0, 1.0, 0.3 and 0.1 mg/kg). No significant differences were observed between the sucrose concentration gradients obtained
under saline and those obtained under naloxone, suggesting that the anorectic effect of naloxone is not primarily determined
by discrimination of sweet taste.
Received: 4 September 1996 / Final version: 16 October 1996 相似文献
5.
目的探讨纳络酮对脂多糖诱导原代培养星形胶质细胞释放谷氨酸的抑制效应。方法体外培养星形胶质细胞于融合状态,随机分为5组(1)对照组(L0 N0);(2)1μg·ml-1脂多糖组(L1 N0);(3)1μg·ml-1脂多糖 0.5μmol·L-1纳络酮组(L1 N0.5);(4)1μg·ml-1脂多糖 1.0μmol·L-1纳络酮组(L1 N1.0);(5)1μg·ml-1脂多糖 2.0μmol·L-1纳络酮组(L1 N2.0)。各组培养液均换成Neurobasal/B27无血清培养液后,在相应组中加入上述相应终浓度的脂多糖和纳络酮,继续培养2h。用反相高效液相色谱分析方法测定各组细胞外液中谷氨酸含量。结果L1 N0组中谷氨酸含量明显高于L0 N0组,其差异有极显著性意义(P<0.05);L1 N0.5、L1 N1.0、L1 N2.0组内谷氨酸的含量则随着纳络酮用量的增加而逐渐降低,其中L1 N2.0组与L1 N0组相比,谷氨酸含量差异有显著性(P<0.05)。结论纳络酮能抑制脂多糖刺激大脑皮质星形胶质细胞释放谷氨酸,具有一定的脑保护作用。 相似文献
6.
联合应用纳洛酮与甲基强的松龙对大鼠急性肺损伤的保护作用 总被引:4,自引:0,他引:4
目的 探讨联合应用甲基强的松龙、纳洛酮对内毒素所致急性肺损伤大鼠的防治作用及可能机制。方法 建立大鼠内毒素吸入性ALI模型 (LPS ,3mg/kg气管内注射 ) ,85只大鼠随机分为生理盐水对照组、内毒素损伤组、甲基强的松龙组 (内毒素 甲基强的松龙 )、纳洛酮组 (内毒素 纳洛酮 )、联合用药组 (内毒素 甲基强的松龙 纳洛酮 )。采用放射免疫方法检测大鼠血清TNF -α、IL - 8水平 ,并观察动脉血气分析及肺组织病理变化。结果 内毒素损伤组较生理盐水组TNF -α、IL - 8水平明显增高 ,动脉血氧分压明显降低 ,肺组织可见肿胀、淤血、炎细胞浸润。联合用药组各项指标较内毒素损伤组均轻。结论 联合应用甲基强的松龙和纳洛酮可降低气管内注入内毒素致大鼠ALI血清TNF -α、IL - 8升高水平 ,减轻肺损伤病理改变程度 ,对大鼠ALI有防治作用 相似文献
7.
200例择期胆囊切除+术中胆道造影患者分二组;芬太尼17ug/kg静注(F组,n=100)、哌替啶1mg/kg静注。评价两种麻醉性镇痛药致Oddi括约肌痉挛的发生率,结果:8例病人造影剂不能通过Oddi括约肌、十二指肠不显影,胆总管下端显示“鸟嘴样”或“假结石”影像,后者3例病人胆总管探查阴性,静注纳络酮0.4mg后,全部病例造影剂顺利进入十二指肠。结论:硬膜外麻醉辅用小剂量芬太尼/哌替啶时Odd 相似文献
8.
采用微量注射法,对37只大鼠进行了实验观察.结果如下:①下丘脑弓状核(ARC)注射神经降压素(NT)可使甩尾反应潜伏期(TFL)或痛阈显著升高.对照组注射生理盐水,TFL无明显变化.②ARC先注射纳洛酮,再注射NT,TFL变化值与单纯注射NT组相比明显下降.③ARC注射β-内啡肽(β-End)抗血清,再注射NT,TFL显著下降.④ARC注射生理盐水不影响注射NT的镇痛效应.上述结果表明,大鼠ARC注射NT可产生明显的镇痛效应,该效应可被ARC预先注射纳洛酮或β-内啡肽抗血清翻转,提示NT在ARC的镇痛作用,部分是由β-End介导的. 相似文献
9.
白细胞介素—2新的功能位点及其中枢镇痛作用 总被引:2,自引:0,他引:2
白细胞介素-2(IL-2)不仅是重要的免疫调节因子,而且还具有重要的中枢调节作用。本实验以钾离子透入引起大鼠甩尾反应为指标,发现侧脑室注射IL—2能显著提高动物痛阈,并能被纳洛酮所阻断,表示IL-2的中枢镇痛作用可能与阿片受体有关。利用基因定位突变技术获得的无免疫活性IL-2实查体仍具有中枢镇痛作用,表明IL—2分子上发挥镇痛和免疫调节作用的功能位点是相互独立的。纳洛酮能够阻断IL—2的中枢镇痛作用,而不能影响IL—2增殖CTLL-2细胞的作用,提示IL-2发挥镇痛和免疫调节作用可能通过不同的受体途径。IL-2分子中第45位Tyr残基突变为Val后,虽仍保留了免疫活性,但丧失了镇痛功能,表示45位Tyr残基是IL—2发挥中枢镇痛功能的关键残基之一。我们推测IL—2的镇痛功能位点可能在IL—2分子中第45位Tyr残基附近区域。 相似文献
10.
Angelo Cagnacci Gian Benedetto Melis Renza Soldani Anna Maria Paoletti Marco Gambacciani Adriana Spinetti Piero Fioretti 《Maturitas》1991,13(4):283-296
The neuroendocrine and clinical effects of transdermal 17β-estradiol (rated at 50 μg/day; TTS 50) were studied in 40 postmenopausal women; ten additional postmenopausal women did not receive any drugs. The changes in LH and rectal temperature induced by the infusion of the opioid antagonist naloxone (10 mg i.v. bolus plus 10 mg/h for 4 h) were used to evaluate the central activity of endogenous opioid peptides. TTS 50 increased opioid activity, as evidenced by the restoration of the LH response (P < 0.01) and the enhancement of the hypothermic effect (P < 0.05) of naloxone. A greater reduction in hot flushes was observed in TTS 50-treated subjects than in untreated women, with the maximal effect of TTS 50 achieved after 3 months of therapy. TTS 50 did not modify the concentrations of circulating lipids, glucose or liver enzymes but reduced the biochemical parameters indicative of bone reabsorption. Bone density of the distal radius significantly increased during TTS 50 (P < 0.02), reaching its maximum value after 6 months of therapy. Thereafter bone density declined, but more slowly than in untreated women.
Our data suggest that TTS 50 has marked neuroendocrine effects, that it diminishes the incidence of hot flushes and reduces bone demineralization. By contrast, it has a very little, if any, metabolic impact on the liver or on glucose and lipid metabolism. 相似文献