全文获取类型
收费全文 | 49938篇 |
免费 | 4665篇 |
国内免费 | 2518篇 |
专业分类
耳鼻咽喉 | 630篇 |
儿科学 | 511篇 |
妇产科学 | 492篇 |
基础医学 | 6751篇 |
口腔科学 | 745篇 |
临床医学 | 5366篇 |
内科学 | 8361篇 |
皮肤病学 | 1341篇 |
神经病学 | 3146篇 |
特种医学 | 2919篇 |
外国民族医学 | 7篇 |
外科学 | 5343篇 |
综合类 | 5223篇 |
现状与发展 | 4篇 |
一般理论 | 8篇 |
预防医学 | 2729篇 |
眼科学 | 1170篇 |
药学 | 5635篇 |
18篇 | |
中国医学 | 2669篇 |
肿瘤学 | 4053篇 |
出版年
2024年 | 206篇 |
2023年 | 787篇 |
2022年 | 1940篇 |
2021年 | 2489篇 |
2020年 | 1563篇 |
2019年 | 1747篇 |
2018年 | 1882篇 |
2017年 | 1694篇 |
2016年 | 1999篇 |
2015年 | 2732篇 |
2014年 | 3163篇 |
2013年 | 3186篇 |
2012年 | 4382篇 |
2011年 | 4452篇 |
2010年 | 2878篇 |
2009年 | 2241篇 |
2008年 | 2716篇 |
2007年 | 2599篇 |
2006年 | 2323篇 |
2005年 | 2199篇 |
2004年 | 1696篇 |
2003年 | 1666篇 |
2002年 | 1427篇 |
2001年 | 1046篇 |
2000年 | 834篇 |
1999年 | 641篇 |
1998年 | 398篇 |
1997年 | 369篇 |
1996年 | 273篇 |
1995年 | 217篇 |
1994年 | 207篇 |
1993年 | 142篇 |
1992年 | 161篇 |
1991年 | 155篇 |
1990年 | 140篇 |
1989年 | 113篇 |
1988年 | 87篇 |
1987年 | 70篇 |
1986年 | 73篇 |
1985年 | 49篇 |
1984年 | 24篇 |
1983年 | 13篇 |
1982年 | 12篇 |
1981年 | 21篇 |
1980年 | 14篇 |
1979年 | 16篇 |
1976年 | 7篇 |
1974年 | 6篇 |
1972年 | 6篇 |
1969年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Ladislav Novotný Hassan Farghali Miloš Ryba Ivo Janků Jiří Beránek 《Cancer chemotherapy and pharmacology》1984,13(3):195-199
Summary Both transport and biotransformation processes for a series of pyrimidine nucleobases, ribonucleosides, 2-deoxyribonucleosides, and acetyl and 5-substituted derivatives of the cancerostatic agent araC were studied in the isolated everted rat jejunum with a continuous perfusion technique. Metabolic alterations during penetration were assessed by HPLC. 5-Halogeno and 5-deoxy derivatives of cytosine nucleosides exhibited higher transport rates and higher stability towards the deamination reaction than did unsubstituted derivatives. Octanol-buffer partition coefficients were estimated for the study compounds, and fragmental constants for the sugar moieties of nucleosides were assessed. With the present study compounds there was no correlation between lipophilicity and transport rate, as previously reported, but there was a correlation between lipophilicity and metabolic alteration of araC derivatives (r=0.99, n=5). 相似文献
52.
Ji-Hye Song Hyunhee Kim Minseok Jeong Min Jung Kong Hyo-Kyoung Choi Woojin Jun Yongjae Kim Kyung-Chul Choi 《Nutrients》2021,13(5)
Metabolic syndrome is a worldwide health problem, and obesity is closely related to type 2 diabetes, cardiovascular disease, hypertension, and cancer. According to WHO in 2018, the prevalence of obesity in 2016 tripled compared to 1975. D. morbifera reduces bad cholesterol and triglycerides levels in the blood and provides various antioxidant nutrients and germicidal sub-stances, as well as selenium, which helps to remove active oxygen. Moreover, D. morbifera is useful for treating cardiovascular diseases, hypertension, hyperlipidemia, and diabetes. Therefore, we study in vivo efficacy of D. morbifera to investigate the prevention effect of obesity and cholesterol. The weight and body fat were effectively reduced by D. morbifera water (DLW) extract administration to high-fat diet-fed C57BL/6 mice compared to those of control mice. The group treated with DLW 500 mg∙kg−1∙d−1 had significantly lower body weights compared to the control group. In addition, High-density lipoprotein (HDL) cholesterol increased in the group treated with DLW 500 mg∙kg−1∙d−1. The effect of DLW on the serum lipid profile could be helpful to prevent obesity. DLW suppresses lipid formation in adipocytes and decreases body fat. In conclusion, DLW can be applied to develop anti-obesity functional foods and other products to reduce body fat. 相似文献
53.
Bradshaw Catherine P. Pas Elise T. Musci Rashelle J. Kush Joseph M. Ryoo Ji Hoon 《Prevention science》2021,22(7):986-1000
Prevention Science - This study examined the impact of a state policy requiring that any school with a habitual truancy rate of 8% or higher to be trained in Tier 1 school-wide Positive Behavioral... 相似文献
54.
Joshua Jeong 《The Journal of adolescent health》2021,68(5):906-913
PurposeAdolescent parenthood is a major challenge in low- and middle-income countries (LMICs). However, the vast majority of the evidence has focused on adolescent motherhood. Little is known about adolescent fatherhood in LMICs. The aim of this study was to examine the determinants of early fatherhood and its consequences on a range of outcomes among adolescent males.MethodsThis study used three waves of longitudinal data from the multicountry Young Lives cohort study, specifically following a sample of 1,779 adolescent boys at ages 15, 19, and 22 years in Ethiopia, India, Peru, and Vietnam. Individual fixed effects models were conducted to investigate the sociodemographic determinants of adolescent fatherhood and the consequences of adolescent fatherhood on males' education, health, psychosocial well-being, and time use outcomes.ResultsThe results indicated that lower educational attainment, absence of the adolescent's mother and father from the home, larger household size, and poverty increased the likelihood of becoming an adolescent father by age 22 years. The results revealed that becoming an adolescent father was associated with a higher likelihood of school dropout, being overweight, smoking, greater internalizing problems, and less time spent on leisure activities and more time spent on caregiving responsibilities.ConclusionsHighlighting the experiences of young men as adolescent parents in LMICs, findings underscore the importance of prevention strategies to delay early parenthood for adolescent boys and multicomponent interventions to support young fathers and their unique health, socioeconomic, psychosocial, and behavioral needs. 相似文献
55.
56.
饮食服务业从业人员乙型肝炎病毒感染动态研究 总被引:1,自引:0,他引:1
目的为了解泰安市饮食服务业从业人员乙型肝炎病毒感染状况。方法应用ELISA方法在1995~1999年对53434名饮食服务业从业人员进行了血清HBsAg、抗-HBc、HBeAg和抗-HBe检测。结果1995~1999年饮食服务业从业人员血清HBsAg、抗-HBc、HBeAg和抗-HBe总阳性率呈逐年下降趋势,依次为4.41%、3.88%、3.46%、2.86%和2.50%,其差异有显著意义(χ 相似文献
57.
低铅染毒大鼠体内脂质过氧化及抗氧化水平改变 总被引:1,自引:0,他引:1
目的:观察低剂量铅染毒后大鼠体内脂质过氧化水平改变,为铅的毒作用机制研究提供依据。方法:以醋酸铅为受试物,雄性Wistar大鼠为受试对象,分别观察其脏器脂质过氧化水平改变。结果:低铅染毒后,大鼠各脏器超氧化物歧化酶(SOD)、谷胱苷肽过氧化物酶(GSH-Px)及过氧化脂质(LPO)均有不同程度改变(P<0.05,P<0.01),而巯基(-SH)含量仅肝脏变化较明显。结论:较低剂量的铅即可引起体内脂质过氧化水平的改变,而这种变化可能是铅的毒作用途径之一。 相似文献
58.
目的 :探讨三氧化二砷 (As2 O3 )对人肺癌细胞株 (Spc- A1)诱导凋亡的机制 ,为抗肿瘤药物的筛选和用药方式提供理论依据。方法 :体外培养 Spc- A1细胞株与不同浓度的 As2 O3 进行作用 ,应用 MTT比色法、流式细胞仪技术、电子显微镜技术观察细胞增殖率、细胞周期率、细胞凋亡率及亚细胞水平变化。结果 :As2 O3 能够抑制 Spc- A1细胞的增殖 ,且呈时间剂量依赖性 ,Spc- A1细胞凋亡率与药物浓度和时间呈依赖关系。电镜观察细胞线粒体肿胀、空泡 ,染色质浓缩、核碎裂。结论 :As2 O3 可诱导 Spc- A1细胞凋亡 ,细胞周期延长 ,线粒体变性。 相似文献
59.
Ithasbeenconsideredbymodernmedicinethatbronchialasthmaisachronicairwayallergicinflammation(AAI)whichisthemajorfactorthatinducesreversibleairwayventilatingdisturbanceandbronchialhyper re sponsiveness(BHR)inasthmaticpatients,aswellasacorrelationbetweent… 相似文献
60.
Wang Ben Deng Yu-xuan Yan Sha Xie Hong-fu Li Ji Jian Dan 《Lasers in medical science》2021,36(3):649-655
Lasers in Medical Science - Acne scarring is one of the most common facial skin disorders. The appropriate treatments for acne scars in patients with rosacea have not been studied. This study was... 相似文献