全文获取类型
收费全文 | 52210篇 |
免费 | 4912篇 |
国内免费 | 1571篇 |
专业分类
耳鼻咽喉 | 133篇 |
儿科学 | 684篇 |
妇产科学 | 961篇 |
基础医学 | 6978篇 |
口腔科学 | 1404篇 |
临床医学 | 5490篇 |
内科学 | 6465篇 |
皮肤病学 | 2057篇 |
神经病学 | 6391篇 |
特种医学 | 1086篇 |
外科学 | 4884篇 |
综合类 | 4621篇 |
现状与发展 | 2篇 |
一般理论 | 1篇 |
预防医学 | 7810篇 |
眼科学 | 554篇 |
药学 | 6075篇 |
24篇 | |
中国医学 | 1887篇 |
肿瘤学 | 1186篇 |
出版年
2024年 | 131篇 |
2023年 | 852篇 |
2022年 | 1277篇 |
2021年 | 2345篇 |
2020年 | 2336篇 |
2019年 | 2035篇 |
2018年 | 1944篇 |
2017年 | 2221篇 |
2016年 | 2353篇 |
2015年 | 2223篇 |
2014年 | 3281篇 |
2013年 | 4973篇 |
2012年 | 2713篇 |
2011年 | 3173篇 |
2010年 | 2478篇 |
2009年 | 2604篇 |
2008年 | 2709篇 |
2007年 | 2306篇 |
2006年 | 2194篇 |
2005年 | 1711篇 |
2004年 | 1589篇 |
2003年 | 1381篇 |
2002年 | 1110篇 |
2001年 | 1047篇 |
2000年 | 820篇 |
1999年 | 708篇 |
1998年 | 736篇 |
1997年 | 661篇 |
1996年 | 627篇 |
1995年 | 483篇 |
1994年 | 429篇 |
1993年 | 347篇 |
1992年 | 403篇 |
1991年 | 364篇 |
1990年 | 304篇 |
1989年 | 304篇 |
1988年 | 258篇 |
1987年 | 174篇 |
1986年 | 177篇 |
1985年 | 189篇 |
1984年 | 156篇 |
1983年 | 97篇 |
1982年 | 104篇 |
1981年 | 78篇 |
1980年 | 76篇 |
1979年 | 63篇 |
1978年 | 48篇 |
1977年 | 32篇 |
1976年 | 28篇 |
1975年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 453 毫秒
991.
《Medical Journal Armed Forces India》2019,75(3):297-302
BackgroundMilitary life leads to a great personal sacrifice and labor in the aircrew because they are constantly subjected to innumerable activities which have a great work pressure; therefore, the aim of this study was to determine the level of work stress associated with bruxism in the aircrew of the Peruvian Air Force.MethodsThis was a cross-sectional study. A total of 204 crew members of the Peruvian Air Force from the Air Group were surveyed, and the stomatological clinical inspection was carried out. Each crew member was evaluated using the validated International Labor Organization-World Health Organization (ILO-WHO) Work Stress Scale, and clinical records were used to diagnose bruxism using the Smith and Knight wear index.ResultsIt was found that 93.7% (n = 191) of the crew members were men and 6.3% (n = 13) were women; and the percentage of intermediate-level stress was found to be high in the grade of non-commissioned officers, whereas in the officer grade, the level of stress was low. There was also a statistically significant association between the variables military grade, sex, and age group. The sub-officers presented a higher percentage in the category "with bruxism", while in the rank of officers the category of "non-bruxism" was the most prevalent.ConclusionsThis study showed a statistically significant association between the variable bruxism and the level of work stress between the military aviators of the Peruvian Air Force (p<0.001). 相似文献
992.
993.
Anthony Walker Ben Rattray Matt Brearley 《Journal of occupational and environmental hygiene》2017,14(4):306-312
Accurately assessing the physiological status of firefighters during work in the heat is critical to ensuring their safety. Evaluating core temperatures (Tc) in the field is problematic due to cost and limitations in technology and accuracy. As such, fire services rely on individual perceptions of wellbeing. The present study aimed to establish whether perceptual responses measured using the perceptual strain index (PeSI), calculated from rate of perceived exertion (RPE) and thermal sensation (TS), could reliably predict the physiological strain (PSI) encountered by experienced firefighters working in a hot environment. We conducted two firefighting simulations (set-pace and self-paced) in a purposefully built heat chamber (100 ± 5°C) comprised of two 20-min periods separated by a 10-min recovery outside the chamber. Physiological strain was measured via heart rate (HR) and gastrointestinal temperature (Tgi) and compared with PeSI at 5-min intervals. To evaluate the predictive ability of the PeSI for PSI, mean differences and the 95% limits of agreement (LOA) were established, along with correlation coefficients at each 5-min interval. Moderately significant correlations occurred in the second work bout of the self-paced trial only (10 min: r = 0.335, 15 min: r = 0.498, 20 min r = 0.439) with no other correlations observed at any other time during either trial or during the rest periods. Bland-Altman analysis revealed mean differences of ?0.74 ± 2.70 (self-paced) and +0.04 ± 2.04 (set-paced) between PeSI and PSI with the 95% LOA being ?4.77 to 3.28 (self-paced) and ?4.01 to 2.01 (set-paced). The wide LOA and lack of correlations observed between perceptual and physiological strain in both self-paced and set-paced work trials indicate that PeSI is not sufficiently reliable as a sole measure of wellbeing for firefighters working in the heat. Hence, we recommend that fire services prioritise the development of reliable and effective monitoring tools for use in the field. 相似文献
994.
Melatonin modulates neonatal brain inflammation through endoplasmic reticulum stress,autophagy, and miR‐34a/silent information regulator 1 pathway 下载免费PDF全文
Elie Saliba Maria Cristina Albertini Sylvie Chalon Mariangela Longini Pierre Gressens Giuseppe Buonocore Walter Balduini 《Journal of pineal research》2016,61(3):370-380
Maternal infection/inflammation represents one of the most important factors involved in the etiology of brain injury in newborns. We investigated the modulating effect of prenatal melatonin on the neonatal brain inflammation process resulting from maternal intraperitoneal (i.p.) lipopolysaccharide (LPS) injections. LPS (300 μg/kg) was administered to pregnant rats at gestational days 19 and 20. Melatonin (5 mg/kg) was administered i.p. at the same time as LPS. Melatonin counteracted the LPS sensitization to a second ibotenate‐induced excitotoxic insult performed on postnatal day (PND) 4. As melatonin succeeded in reducing microglial activation in neonatal brain at PND1, pathways previously implicated in brain inflammation regulation, such as endoplasmic reticulum (ER) stress, autophagy and silent information regulator 1 (SIRT1), a melatonin target, were assessed at the same time‐point in our experimental groups. Results showed that maternal LPS administrations resulted in an increase in CHOP and Hsp70 protein expression and eIF2α phosphorylation, indicative of activation of the unfolded protein response consequent to ER stress, and a slighter decrease in the autophagy process, determined by reduced lipidated LC3 and increased p62 expression. LPS‐induced inflammation also reduced brain SIRT1 expression and affected the expression of miR‐34a, miR146a, and miR‐126. All these effects were blocked by melatonin. Cleaved‐caspase‐3 apoptosis pathway did not seem to be implicated in the noxious effect of LPS on the PND1 brain. We conclude that melatonin is effective in reducing maternal LPS‐induced neonatal inflammation and related brain injury. Its role as a prophylactic/therapeutic drug deserves to be investigated by clinical studies. 相似文献
995.
【In Press】 Protective effect of pomegranate juice on retinal oxidative stress in streptozotocin-induced diabetic rats 下载免费PDF全文
AIM: To investigate the effect of pomegranate juice (PJ) intake on overall oxidation status in retinas of diabetic rats.
METHODS: Twenty-seven rats were divided into four groups as control (CO), diabetic (DM), control treated with PC (CO-PJ), and diabetic treated with PJ (DM-PJ).The retina tissues were used to determine 8-Hydroxy-2’-deoxyguanosine (8OHdG), malondialdehyde (MDA), reduced glutathione (GSH) levels, and the enzyme activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px).
RESULTS: The levels of 8OHdG and MDA were significantly increased in the retina of DM group compared to CO group (p=0.001, p<0.001 respectively). Both 8OHdG and MDA levels were decreased in PJ-DM group compared to DM group (p=0.004, p<0.001 respectively). The activities of antioxidant enzymes GSH, SOD, and GDH-Px were significantly decreased in the retina of DM group compared to CO group (p≤0.01). GSH and GSH-Px activities were higher in PJ-DM group compared with DM group (p=0.010, p=0.042, respectively) but SOD activity was not statistically different (p=0.938).
CONCLUSION: PJ intake was found to be effective in decreasing oxidative end products, and in increasing the activities of antioxidant enzymes in diabetic retinas of rats, which suggests it may be effective against oxidative stress in diabetic retinas. 相似文献
996.
997.
目的:观察黄芩苷、二甲双胍和氨基胍对D-半乳糖诱导大鼠体内蛋白非酶糖基化-氧化应激、醛糖还原酶活性及胰岛素抵抗作用。方法:清洁级健康SD大鼠90只,完全随机分为6组正常对照组、模型对照组、氨基胍组、二甲双胍组、黄芩苷高剂量和黄芩苷低剂量组,每组各15只。除空白对照组外,其余组大鼠均采用腹腔注射D-gal,灌胃;结束时观察各组大鼠晚期糖基化终末产物、糖化血红蛋白、胰岛素等,并计算胰岛素敏感指数,醛糖还原酶和超氧化物歧化酶的活性。结果:D-gal处理大鼠出现血糖升高、糖耐量减退、糖基化产物及胰岛素含量增高,SOD活性降低及红细胞内AR活性增强;Met,AG以及Bai高和低剂量均能改善D-gal诱导大鼠IGT和降低糖基化产物和胰岛素含量。结论:D-gal诱导能使大鼠体内糖基化反应、胰岛素抵抗和醛糖还原酶活性增强;Bai,Met和AG能抑制蛋白非酶糖基化反应和醛糖还原酶活性,改善高胰岛素血症。 相似文献
998.
《Renal failure》2013,35(8):1124-1129
AbstractObjective: The objective of this study is to evaluate the effect and mechanism of mitochondria-targeted peptides (MTP131 and SPI20) on contrast-induced acute kidney injury (CI-AKI) in rats with hypercholesterolemia. Method: Forty SD rats were randomly divided into normal diet group (NN, n?=?8) and high cholesterol supplemented dietary group (HN, n?=?32). At the end of 8 weeks, the group HN was divided into four subgroups. All Rats were given injection of either diatrizoate (10?mL/kg) or equal volume of normal saline, the rats pretreated with MTP131 or SPI20 were given injection with MTP131 or SPI 20 (3?mg/kg) by peritoneal cavity for 3 times. Blood, urine and renal tissue samples were prepared to determine biochemical parameters. The renal pathological changes were evaluated by hematoxylin and eosin staining and scored semiquantitatively, The protein expression of renal NOX4 was also measured by Western blotting. Results: In diatrizoate-injected rats, Serum creatinine (Scr), fractional excretion of sodium (FeNa%), fractional excretion of potassium (FeK%), pathological scores, renal malondialdehyde (MDA) content, the NADPH oxidase activity and the expression of NOX4 in kidney tissue were significantly increased (p?<?0.01). In the groups pretreated with MTP131 or SPI20, the levels of Scr, FeNa%, FeK%, MDA content and NADPH oxidase activity in renal tissue decreased (p?<?0.01), the levels of renal super oxygen dehydrogenises and ATPase activity increased (p?<?0.01). The renal injuries induced by contrast media (CM) were alleviated. Conclusion: MTP131 and SPI20 might protect acute kidney injury induced by CM in rats with hypercholesterolemia. 相似文献
999.
Swedish legislation and international norms emphasize society's obligation to ensure general accessibility. The possibility of independent outdoor mobility, transportation, and travel are as important for individuals with reduced functional capacity as for other members of society, but today their mobility is limited. The aim of this article is to outline a novel field for research collaboration between occupational therapy and traffic planning and engineering, focusing on person-environment relationships with an explicit orientation towards advantages to society. Target groups are elderly people and individuals with impairments, and their relation to public transportation provided by society, in terms of general accessibility. Topical research from both disciplines is presented and synthesized, leading to the formulation of joint research questions. The collaborative approach presented increases the potential for continuing, comprehensive, and stable growth of knowledge. The intention is to assist the legislative process in the development of society, leading to a more efficient use of available economic resources. The ultimate objective of future research projects will be to gain knowledge that will facilitate improvements in public health. 相似文献
1000.
目的 对职业性三硝基甲苯(TNT)白内障患者治疗前后眼部血流动力学改变进行分析,了解其治疗效果.方法 对广西壮族自治区职业病防治研究院2010-2012年期间收治45例职业性TNT白内障患者的临床资料进行回顾性的分析,采用黄芪注射液联合还原型谷胱甘肽滴眼液对45例患者实施治疗,B超检查眼动脉、视网膜中央动脉血流改变情况,比较、分析治疗前、后的眼部血流动力学情况.结果 经过一段的时间的治疗以后,45例职业性TNT白内障患者眼部的眼动脉收缩期的平均血流速度、眼动脉舒张期的平均血流速度、视网膜中央动脉收缩期的平均血流速度、视网膜中央动脉舒张期的平均血流速度与治疗前比较都有提高,其中眼动脉和视网膜中央动脉收缩期血流速度与治疗前比较差异具有统计学意义(P<0.05).结论 职业性TNT白内障患者,其眼部周围的血液循环存在供血不足的问题,采用黄芪注射液联合还原型谷胱甘肽滴眼液的治疗方法来扩张眼部血管、增加眼部血流量,对于改善TNT白内障患者眼部的血流动力、促进其视力恢复具有积极意义. 相似文献