全文获取类型
收费全文 | 5146篇 |
免费 | 391篇 |
国内免费 | 42篇 |
专业分类
耳鼻咽喉 | 28篇 |
儿科学 | 151篇 |
妇产科学 | 90篇 |
基础医学 | 628篇 |
口腔科学 | 194篇 |
临床医学 | 470篇 |
内科学 | 1120篇 |
皮肤病学 | 92篇 |
神经病学 | 277篇 |
特种医学 | 206篇 |
外科学 | 814篇 |
综合类 | 303篇 |
一般理论 | 5篇 |
预防医学 | 407篇 |
眼科学 | 161篇 |
药学 | 315篇 |
中国医学 | 10篇 |
肿瘤学 | 308篇 |
出版年
2023年 | 47篇 |
2022年 | 95篇 |
2021年 | 170篇 |
2020年 | 113篇 |
2019年 | 132篇 |
2018年 | 144篇 |
2017年 | 119篇 |
2016年 | 132篇 |
2015年 | 123篇 |
2014年 | 149篇 |
2013年 | 189篇 |
2012年 | 320篇 |
2011年 | 299篇 |
2010年 | 172篇 |
2009年 | 183篇 |
2008年 | 221篇 |
2007年 | 261篇 |
2006年 | 227篇 |
2005年 | 224篇 |
2004年 | 190篇 |
2003年 | 187篇 |
2002年 | 172篇 |
2001年 | 140篇 |
2000年 | 158篇 |
1999年 | 128篇 |
1998年 | 84篇 |
1997年 | 78篇 |
1996年 | 64篇 |
1995年 | 60篇 |
1994年 | 44篇 |
1993年 | 41篇 |
1992年 | 56篇 |
1991年 | 67篇 |
1990年 | 72篇 |
1989年 | 78篇 |
1988年 | 63篇 |
1987年 | 60篇 |
1986年 | 57篇 |
1985年 | 49篇 |
1984年 | 37篇 |
1983年 | 36篇 |
1982年 | 38篇 |
1981年 | 37篇 |
1980年 | 34篇 |
1979年 | 31篇 |
1978年 | 28篇 |
1977年 | 26篇 |
1976年 | 26篇 |
1975年 | 23篇 |
1973年 | 19篇 |
排序方式: 共有5579条查询结果,搜索用时 15 毫秒
61.
Delay times and management of acute myocardial infarction in indigenous and non-indigenous people in the Northern Territory 总被引:2,自引:0,他引:2
OBJECTIVES: To investigate differences in presentation and management of Indigenous and non-Indigenous patients hospitalised with acute myocardial infarction (AMI). DESIGN: Retrospective review of hospital medical records. PARTICIPANTS AND SETTING: 122 patients with definite or possible AMI admitted to hospitals in the Top End of the Northern Territory (NT) in 1996. MAIN OUTCOME MEASURES: Percentage receiving thrombolytic therapy; delays from symptom onset to primary and emergency department presentations, first and diagnostic electrocardiograms, thrombolytic therapy and aspirin; drugs prescribed during hospitalisation. RESULTS: Thrombolytic therapy was given to 12/41 Indigenous patients (29%) and 38/81 non-Indigenous patients (47%) (P = 0.06). Presentation delay over 12 hours was the reason for not giving thrombolytic therapy for 14/29 Indigenous patients (48%) and 8/43 non-Indigenous patients (19%) (P < 0.01). Median delay times were longer for Indigenous patients for all six categories of delay, although the difference was significant only for delay to emergency department presentation (10:00 versus 3:26 hours; P < 0.01) and to diagnostic electrocardiogram (8:10 versus 3:50 hours; P < 0.01). Delays were also longer for patients from rural compared with urban areas. Once diagnosed, Indigenous patients were as likely as non-Indigenous patients to receive aspirin (93% versus 96%) and beta-blockers (70% versus 69%) and more likely to receive angiotensin-converting enzyme inhibitors (60% versus 40%; P = 0.03). CONCLUSIONS: Delays in presentation affect Indigenous people living in rural and urban areas as well as non-Indigenous people living in rural areas. Concerted efforts are needed to improve health service access in rural areas and to encourage Indigenous people with persistent chest pain to present earlier. 相似文献
62.
A randomised, prospective trial was conducted to assess the efficacy of various means of alleviating the pain of subcutaneous lidocaine infiltration. One hundred and twenty-two patients were randomly allocated to different groups to receive buffered lidocaine 1%, warmed lidocaine 1% or infiltration by the counter-irritation technique. A visual analogue pain score was recorded at different stages of cannulation and results showed that pain scores were significantly lower in the group receiving buffered lidocaine 1% (p < 0.02) and in the counter-irritation group (p < 0.05). Thus buffering lidocaine 1% and administration of lidocaine 1% by the counter-irritation technique is effective in relieving the pain of lidocaine infiltration. 相似文献
63.
Chow PK Yu WK Ng TH Ong HS Ooi PJ Chan ST Aw SE Soo KC 《The Journal of surgical research》2000,89(1):66-73
Transabdominal duplex Doppler ultrasonography (TDDU) is commonly used for measuring hepatic blood flow (HBF) in clinical practice. Flow velocity and the cross-sectional area (CSA) of vessels are obtained separately and used to compute blood flow. Respiration and changes in portal pressure are known to cause variations in the CSA of the portal vein, but the impact of these parameters on TDDU measurement of portal blood flow is unclear. Eight Yorkshire pigs (20.7-25.1 kg) were used for the study. TDDU determination of portal blood flow was carried out using CSA of the portal vein obtained at inspiration (maximal) and at expiration (minimal) for computation, and the differences obtained were compared. Determination of HBF was carried out simultaneously on the same animals using diisopropyliminodiacetic acid (DISIDA) clearance. A physiological increase in portal pressure was then created by 50% hepatectomy and TDDU measurement similarly carried out on the second postoperative day. Computing portal blood flow in the intact liver using maximal and minimal CSA gave rise to a mean difference of 7.0 ml kg(-1) min(-1) (P < 0.001). A significant correlation was obtained between HBF and portal flow computed from maximal CSA (Pearson's correlation = 0.85, P < 0.033). The respiratory index of the portal vein (maximal CSA/minimal CSA) decreased from 1.5 to 1.2 after hepatectomy, which also caused a 90% increase in portal pressure. Respiration and portal pressure thus significantly impact on TDDU determination of HBF, and in this porcine model, computation using maximal CS more accurately reflects HBF. 相似文献
64.
65.
66.
67.
Gabriela de Freitas Laiber Pascoal Marina Vilar Geraldi Mrio Roberto Marstica Jr. Thomas Prates Ong 《Nutrients》2022,14(10)
Infertility is a growing public health problem. Consumption of antioxidant bioactive food compounds (BFCs) that include micronutrients and non-nutrients has been highlighted as a potential strategy to protect against oxidative and inflammatory damage in the male reproductive system induced by obesity, alcohol, and toxicants and, thus, improve spermatogenesis and the fertility parameters. Paternal consumption of such dietary compounds could not only benefit the fathers but their offspring as well. Studies in the new field of paternal origins of health and disease show that paternal malnutrition can alter sperm epigenome, and this can alter fetal development and program an increased risk of metabolic diseases and breast cancer in adulthood. BFCs, such as ascorbic acid, α-tocopherol, polyunsaturated fatty acids, trace elements, carnitines, N-acetylcysteine, and coenzyme Q10, have been shown to improve male gametogenesis, modulate epigenetics of germ cells, and the epigenetic signature of the offspring, restoring offspring metabolic health induced by stressors during early life. This indicates that, from a father’s perspective, preconception is a valuable window of opportunity to start potential nutritional interventions with these BFCs to maximize sperm epigenetic integrity and promote adequate fetal growth and development, thus preventing chronic disease in adulthood. 相似文献
68.
69.
Pregnenolone and its sulphate had concentration-dependent dual actions on gamma-aminobutyric acid (GABAA)-receptor-mediated ileal contractile responses, enhancing at 0.001-1 microM but inhibiting at 10 microM. There was a sinistral shift of the GABA dose-response curve in the presence of 0.01 microM pregnenolone, with a significant potentiation over the lower concentration range of GABA (3-30 microM), whilst 10 microM pregnenolone depressed the curve by 50% without a significant change in the EC50, in a manner resembling non-competitive inhibition with picrotoxin. Pregnenolone and its sulphate evidently have modulatory actions at ileal GABAA-receptor complexes in keeping with those seen using neurochemical studies in the central nervous system. 相似文献
70.
广义负二项分布对钉螺分布的拟合 总被引:2,自引:1,他引:2
目的介绍并应用广义负二项分布研究湖北钉螺的分布规律,为定量化研究提供理论依据。方法随机抽取安徽省池州市贵池区秋浦河沿岸的4块滩地作为研究现场,2005年调查4块滩地的钉螺数据,2006年从中再随机抽取2块滩地进行调查。通过全局最大似然法分别拟合广义负二项分布和负二项分布,比较同一季节不同滩地和不同季节同一滩地的分布拟合结果。结果不同季节、不同滩地的钉螺密度是不同的,但其分布形状均是相似的正偏态分布,广义负二项分布能成功地拟合所有的钉螺数据。不同季节同一滩地问的广义负二项分布参数的变化不一致,同一季节不同滩地广义负二项分布的参数估计结果即使在钉螺密度相近的情况下也不相近,钉螺生存环境的微小差异可以通过广义负二项分布的参数灵敏反映。结论广义负二项分布比负二项分布能更好地反映钉螺分布的复杂性,其将在钉螺的定量化研究领域以及家庭聚集性疾病、寄生虫病和定量生态学的研究中具有重要意义。 相似文献