全文获取类型
收费全文 | 64324篇 |
免费 | 3770篇 |
国内免费 | 252篇 |
专业分类
耳鼻咽喉 | 896篇 |
儿科学 | 1618篇 |
妇产科学 | 1393篇 |
基础医学 | 8992篇 |
口腔科学 | 4184篇 |
临床医学 | 5206篇 |
内科学 | 13975篇 |
皮肤病学 | 1677篇 |
神经病学 | 5591篇 |
特种医学 | 1534篇 |
外国民族医学 | 1篇 |
外科学 | 7283篇 |
综合类 | 356篇 |
一般理论 | 16篇 |
预防医学 | 6491篇 |
眼科学 | 1205篇 |
药学 | 4660篇 |
中国医学 | 477篇 |
肿瘤学 | 2791篇 |
出版年
2023年 | 517篇 |
2022年 | 972篇 |
2021年 | 2280篇 |
2020年 | 1334篇 |
2019年 | 1965篇 |
2018年 | 2395篇 |
2017年 | 1626篇 |
2016年 | 1759篇 |
2015年 | 2027篇 |
2014年 | 2671篇 |
2013年 | 3424篇 |
2012年 | 5055篇 |
2011年 | 5470篇 |
2010年 | 2842篇 |
2009年 | 2284篇 |
2008年 | 3931篇 |
2007年 | 3899篇 |
2006年 | 3481篇 |
2005年 | 3214篇 |
2004年 | 2979篇 |
2003年 | 2541篇 |
2002年 | 2329篇 |
2001年 | 1286篇 |
2000年 | 1249篇 |
1999年 | 1040篇 |
1998年 | 395篇 |
1997年 | 280篇 |
1996年 | 282篇 |
1995年 | 196篇 |
1994年 | 189篇 |
1993年 | 148篇 |
1992年 | 424篇 |
1991年 | 397篇 |
1990年 | 344篇 |
1989年 | 296篇 |
1988年 | 280篇 |
1987年 | 246篇 |
1986年 | 239篇 |
1985年 | 204篇 |
1984年 | 196篇 |
1983年 | 157篇 |
1982年 | 95篇 |
1981年 | 102篇 |
1980年 | 96篇 |
1979年 | 135篇 |
1978年 | 95篇 |
1975年 | 76篇 |
1971年 | 82篇 |
1969年 | 73篇 |
1967年 | 81篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
921.
Melatonin enhances neural stem cell differentiation and engraftment by increasing mitochondrial function
下载免费PDF全文
![点击此处可从《Journal of pineal research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Miguel Mendivil‐Perez Viviana Soto‐Mercado Ana Guerra‐Librero Beatriz I. Fernandez‐Gil Javier Florido Ying‐Qiang Shen Miguel A. Tejada Vivian Capilla‐Gonzalez Iryna Rusanova José M. Garcia‐Verdugo Darío Acuña‐Castroviejo Luis Carlos López Carlos Velez‐Pardo Marlene Jimenez‐Del‐Rio José M. Ferrer Germaine Escames 《Journal of pineal research》2017,63(2)
Neural stem cells (NSCs) are regarded as a promising therapeutic approach to protecting and restoring damaged neurons in neurodegenerative diseases (NDs) such as Parkinson's disease and Alzheimer's disease (PD and AD, respectively). However, new research suggests that NSC differentiation is required to make this strategy effective. Several studies have demonstrated that melatonin increases mature neuronal markers, which reflects NSC differentiation into neurons. Nevertheless, the possible involvement of mitochondria in the effects of melatonin during NSC differentiation has not yet been fully established. We therefore tested the impact of melatonin on NSC proliferation and differentiation in an attempt to determine whether these actions depend on modulating mitochondrial activity. We measured proliferation and differentiation markers, mitochondrial structural and functional parameters as well as oxidative stress indicators and also evaluated cell transplant engraftment. This enabled us to show that melatonin (25 μM) induces NSC differentiation into oligodendrocytes and neurons. These effects depend on increased mitochondrial mass/DNA/complexes, mitochondrial respiration, and membrane potential as well as ATP synthesis in NSCs. It is also interesting to note that melatonin prevented oxidative stress caused by high levels of mitochondrial activity. Finally, we found that melatonin enriches NSC engraftment in the ND mouse model following transplantation. We concluded that a combined therapy involving transplantation of NSCs pretreated with pharmacological doses of melatonin could efficiently restore neuronal cell populations in PD and AD mouse models depending on mitochondrial activity promotion. 相似文献
922.
Luciamare Perinetti Alves Martins Roberto Esteves Pires Castanho Adriano Barbosa Nogueira Otavio Turolo da Silva Alex Silva de Gusmão 《The Brazilian journal of infectious diseases》2011,15(2):116-118
ObjectiveTo verify the incidence of T. cruzi transmission through breastfeeding during acute experimental Chagas’ disease.MethodsFifteen female Swiss mice were mated and, after pregnancy confirmation, placed in individual cages. A few hours after birth, the females were inoculated with 0.1 mL of blood containing approximately 3 × 105 trypomastigote forms of Y strain of T. cruzi and continued breastfeeding for 25 days.ResultsIn 142 offspring examined no infection through breastfeeding was observed.ConclusionsThe low number of trypomastigote forms ingested by the newborn mice combined with biological and biochemical characteristics of blood trypomastigotes may explain the lack of transmission in this experiment. 相似文献
923.
Andresa Marques de Mattos Larissa Vieira Marino Paula Payão Ovidio Alceu Afonso Jordão Carla Cristina Almeida Paula Garcia Chiarello 《Therapeutic apheresis and dialysis : official peer-reviewed journal of the International Society for Apheresis, the Japanese Society for Apheresis, the Japanese Society for Dialysis Therapy》2012,16(1):68-74
Our aim was to investigate and determine the associations between oxidative stress (OS), dyslipidemia and inflammation in patients treated with continuous ambulatory peritoneal dialysis (CAPD) and hemodialysis (HD) using observational cross‐sectional study. Twenty patients in CAPD and 48 in HD for at least 8 weeks and aged ≥18 years were included in the study. Individuals with malignant or acute inflammatory disease were excluded. A control group of 17 healthy individuals was also recruited. The biochemical parameter evaluations were analyzed using colorimetric kits for albumin, serum glucose, total cholesterol (TC) and lipid fractions. To determine the inflammatory status, CRP, IL‐6 and TNF‐α were analyzed by automated chemiluminescence kits. Plasma advanced oxidation protein products (AOPP) were determined by spectrophotometry. Mean AOPP levels were significantly higher for the HD group compared to the control, and there was no difference in AOPP concentrations between the control and CAPD groups. Dialysis patients had levels of inflammatory parameters higher than controls, and showed a high prevalence of patients with dyslipidemia, especially in CAPD. In the HD group, AOPP was positively correlated with triglycerides (TG) and inversely associated with HDL. Also the HD group was observed to have negative associations between TNF‐α and HDL, LDL and TC. In the CAPD group, CRP was inversely correlated with HDL. Hemodialysis patients had increased protein OS and associations of inflammation and dyslipidemia were also observed in these dialysis groups. A more detailed characterization of the relations between oxidative stress and other more traditional risk factors has therapeutic importance, since cardiovascular diseases are the leading cause of death among dialysis patients. 相似文献
924.
925.
926.
16‐Year follow‐up of an avulsed maxillary central incisor after replantation following 10‐h storage: An unusual case
下载免费PDF全文
![点击此处可从《Special care in dentistry》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Tooth avulsion is a type of dental injury defined as the complete displacement of a tooth out of the alveolar socket, and the lack of prompt treatment measures can result in the loss of function, poor quality of life, and psychological and social problems. However, several factors may not permit the immediate replantation of an avulsed tooth; therefore, delayed replantation has emerged as an alternative to meet the esthetic, functional, and psychological demands of patients. Here it was described that the successful replantation of an avulsed maxillary central incisor in a 9‐year‐old boy who presented at the clinic with the tooth stored in unfavorable conditions as dry and then in olive oil‐milk mixture almost 10 h after the event. The tooth has remained in its socket healthy for 16 years after treatment. The patient was satisfied with both esthetics and function. 相似文献
927.
Giovanna Cristina dos Santos Caixeta Flávia Doná Juliana Maria Gazzola 《Revista brasileira de otorrinolaringologia (English ed.)》2012,78(2):87-95
Abnormal body balance and cognitive dysfunction may develop in elderly patients with chronic vestibular dysfunction.AimTo evaluate the relationship between cognitive processing and body balance in elderly patients with chronic peripheral vestibular disease. Type of Study: Cross-sectional.MethodsSeventy-six patients (≥ 60 years) with chronic peripheral vestibular dysfunction and dizziness for more than three months were enrolled. The tests for investigating body balance were: the Berg Balance Scale (BBS), Dynamic Gait Index (DGI), Timed Up and Go Test (TUGT) Timed Up and Go Test modified (TUGTm); the Mini Mental State Examination (MMSE), Test Clock (RT,) and Verbal Fluency Test (VF) were applied for assessing cognition.ResultsThe mean age was 69.03 years (SD=6.21 years); most were female (82.9%). There was a significant negative correlation between the MMSE and the TUGT (ρ=-0.312; p=0.01), MMSE and TUGTm (ρ=-0.306; p=0.01), FV and TUGT (ρ=-0.346; p=0.01), and FV and TUGTm (ρ=-0.536; p=0.01); there was a significant positive correlation between the TR and BBS (ρ=0.343; p=0.01), TR and DGI (ρ=0.298; p=0.01), FV and BBS (ρ=0.299; p=0.01), and FV and DGI (ρ=0.306; p=0.01).ConclusionElderly patients with chronic peripheral vestibular disease and worse performance in body balance tests have functional impairment in cognitive skills. 相似文献
928.
929.
Yun Sung Jo Gui Se Ra Lee Narinay Kim Dong Gyu Jang Sa Jin Kim Young Lee 《International journal of medical sciences》2012,9(9):738-742
Background: The purpose of this research is to discover whether measurement of cervical length and cervical volume at term is helpful in predicting the onset of labor in VBAC candidates.Methods: Transvaginal sonographic evaluations of the cervixes of pregnant women who desired to undergo VBAC were performed between 36 - 40 weeks gestation. Clinical information such as labor onset time, gestational age at delivery and delivery mode was gathered from medical records.Results: A total of 514 pregnant women participated in this study. Cervical length was significantly longer in the group that delivered 7 days or more after measurement than in the group that delivered within 7 days of measurement (43±0.77 cm vs. 2.99±0.72 cm, p< 0.001). Cervical volume was significantly larger in the group that delivered at and after 7 days than in the group that delivered within 7 days (29.21±11.62 cm3 vs. 34.07±13.41 cm3, p=0.014). The cervical length ROC curve was significantly more predictive than the cervical volume ROC curve (AUC: 0.711 vs 0.594, p= 0.001). There were no significant differences between the combined cervical length/volume ROC curve and the cervical length ROC curve alone (p= 0.565). The AUC of the cervical length ROC curve to predict postterm pregnancy was 0.729.Conclusion: Measuring cervical length is helpful in predicting the onset of spontaneous labor within 7 days and posterm delivery in VBAC candidates. 相似文献
930.