全文获取类型
收费全文 | 18486篇 |
免费 | 1447篇 |
国内免费 | 51篇 |
专业分类
耳鼻咽喉 | 136篇 |
儿科学 | 637篇 |
妇产科学 | 482篇 |
基础医学 | 2954篇 |
口腔科学 | 316篇 |
临床医学 | 2157篇 |
内科学 | 3359篇 |
皮肤病学 | 378篇 |
神经病学 | 2146篇 |
特种医学 | 407篇 |
外科学 | 2036篇 |
综合类 | 84篇 |
一般理论 | 23篇 |
预防医学 | 1991篇 |
眼科学 | 314篇 |
药学 | 1109篇 |
中国医学 | 34篇 |
肿瘤学 | 1421篇 |
出版年
2024年 | 37篇 |
2023年 | 212篇 |
2022年 | 419篇 |
2021年 | 799篇 |
2020年 | 500篇 |
2019年 | 702篇 |
2018年 | 712篇 |
2017年 | 573篇 |
2016年 | 621篇 |
2015年 | 656篇 |
2014年 | 840篇 |
2013年 | 1141篇 |
2012年 | 1612篇 |
2011年 | 1610篇 |
2010年 | 754篇 |
2009年 | 713篇 |
2008年 | 1229篇 |
2007年 | 1179篇 |
2006年 | 1052篇 |
2005年 | 1037篇 |
2004年 | 959篇 |
2003年 | 837篇 |
2002年 | 721篇 |
2001年 | 121篇 |
2000年 | 59篇 |
1999年 | 90篇 |
1998年 | 127篇 |
1997年 | 106篇 |
1996年 | 69篇 |
1995年 | 60篇 |
1994年 | 53篇 |
1993年 | 44篇 |
1992年 | 31篇 |
1991年 | 26篇 |
1990年 | 23篇 |
1989年 | 21篇 |
1988年 | 19篇 |
1987年 | 27篇 |
1986年 | 14篇 |
1985年 | 14篇 |
1984年 | 15篇 |
1983年 | 17篇 |
1982年 | 24篇 |
1981年 | 19篇 |
1980年 | 17篇 |
1979年 | 9篇 |
1978年 | 7篇 |
1977年 | 9篇 |
1976年 | 5篇 |
1974年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Nicole Fakhoury Sayegh Gessica N. H. A. Heraoui Hassan Younes Lea Nicole Sayegh Christa Boulos Raymond Sayegh 《Nutrients》2022,14(12)
Non-alcoholic fatty liver disease (NAFLD) is considered the most common liver injury worldwide. NAFLD can evolve into non-alcoholic steatohepatitis (NASH) with or without fibrosis. The objectives of this study were to determine the nutritional profile and dietary patterns of NAFLD Lebanese patients and to report the type of diet-related to the presence of hepatic fibrosis. We hypothesized that the traditional pattern was related to a low risk of fibrosis. This cross-sectional study included 320 eligible Lebanese NAFLD patients. Three dietary patterns were identified: the Traditional diet, the High Fruit diet, and the Westernized diet. Multivariate analysis showed a significant relationship between high adherence to the traditional diet and absence of hepatic fibrosis with a decreased risk of 82%, p = 0.031 after adjusting for its covariables. Fruits were absent from this dietary pattern. Although our results pointed to a possible relationship between fibrosis in NAFLD patients and fruit intake, experimental studies are needed to show whether this is a causal relationship. However, the results obtained in this study may contribute to the planning of dietary interventions and recommendations and enable a better follow-up for NAFLD patients with fibrosis. 相似文献
102.
Nicole Fowle Brenna Garrett OZandra L. Floyd Jennifer Collins Aaron D. Krasnow Mario Islas Steven C. Holland Matthew F. Smith Efrem S. Lim Nicole M. Jarrett Sarah E. Scott 《Emerging infectious diseases》2022,28(7):1520
We investigated a university-affiliated cohort of SARS-CoV-2 Omicron BA.2 infections in Arizona, USA. Of 44 cases, 43 were among students; 26 persons were symptomatic, 8 sought medical care, but none were hospitalized. Most (55%) persons had completed a primary vaccine series; 8 received booster vaccines. BA.2 infection was mild in this young cohort. 相似文献
103.
Philip C. Robinson David F. L. Liew Helen L. Tanner John R. Grainger Raymond A. Dwek Ronald B. Reisler Lawrence Steinman Marc Feldmann Ling-Pei Ho Tracy Hussell Paul Moss Duncan Richards Nicole Zitzmann 《Proceedings of the National Academy of Sciences of the United States of America》2022,119(15)
The emergence of SARS-CoV-2 triggering the COVID-19 pandemic ranks as arguably the greatest medical emergency of the last century. COVID-19 has highlighted health disparities both within and between countries and will leave a lasting impact on global society. Nonetheless, substantial investment in life sciences over recent decades has facilitated a rapid scientific response with innovations in viral characterization, testing, and sequencing. Perhaps most remarkably, this permitted the development of highly effective vaccines, which are being distributed globally at unprecedented speed. In contrast, drug treatments for the established disease have delivered limited benefits so far. Innovative and rapid approaches in the design and execution of large-scale clinical trials and repurposing of existing drugs have saved many lives; however, many more remain at risk. In this review we describe challenges and unmet needs, discuss existing therapeutics, and address future opportunities. Consideration is given to factors that have hindered drug development in order to support planning for the next pandemic challenge and to allow rapid and cost-effective development of new therapeutics with equitable delivery. 相似文献
104.
Ryan C. Higgins Kathleen L. Keller Jane C. Aruma Travis D. Masterson Shana Adise Nicole Fearnbach Wendy M. Stein Laural K. English Bari Fuchs Alaina L. Pearce 《Maternal & child nutrition》2022,18(3)
Longer exclusive breastfeeding duration has been associated with differences in neural development, better satiety responsiveness, and decreased risk for childhood obesity. Given hippocampus sensitivity to diet and potential role in the integration of satiety signals, hippocampus may play a role in these relationships. We conducted a secondary analysis of 149, 7–11‐year‐olds (73 males) who participated in one of five studies that assessed neural responses to food cues. Hippocampal grey matter volume was extracted from structural scans using CAT12, weight status was assessed using age‐ and sex‐adjusted body mass index (%BMIp85), and parents reported exclusive breastfeeding duration and satiety responsiveness (Children''s Eating Behaviour Questionnaire). Separate path models for left and right hippocampus tested: (1) the direct effect of exclusive breastfeeding on satiety responsiveness and its indirect effect through hippocampal grey matter volume; (2) the direct effect of hippocampal grey matter volume on %BMIp85 and its indirect effect through satiety responsiveness. %BMIp85 was adjusted for maternal education, yearly income, and premature birth while hippocampal grey matter volume was adjusted for total intercranial volume, age, and study from which data were extracted. Longer exclusive breastfeeding duration was associated with greater bilateral hippocampal grey matter volumes. In addition, better satiety responsiveness and greater left hippocampal grey matter volume were both associated with lower %BMIp85. However, hippocampal grey matter volumes were not associated with satiety responsiveness. Although no relationship was found between breastfeeding and child weight status, these results highlight the potential impact of exclusive breastfeeding duration on the hippocampal structure. 相似文献
105.
Amy C. Morrison Robert C. Reiner Jr. William H. Elson Helvio Astete Carolina Guevara Clara del Aguila Isabel Bazan Crystyan Siles Patricia Barrera Anna B. Kawiecki Christopher M. Barker Gissella M. Vasquez Karin Escobedo-Vargas Carmen Flores-Mendoza Alfredo A. Huaman Mariana Leguia Maria E. Silva Sarah A. Jenkins Wesley R. Campbell Eugenio J. Abente Robert D. Hontz Valerie A. Paz-Soldan John P. Grieco Neil F. Lobo Thomas W. Scott Nicole L. Achee 《Proceedings of the National Academy of Sciences of the United States of America》2022,119(26)
Over half the world’s population is at risk for viruses transmitted by Aedes mosquitoes, such as dengue and Zika. The primary vector, Aedes aegypti, thrives in urban environments. Despite decades of effort, cases and geographic range of Aedes-borne viruses (ABVs) continue to expand. Rigorously proven vector control interventions that measure protective efficacy against ABV diseases are limited to Wolbachia in a single trial in Indonesia and do not include any chemical intervention. Spatial repellents, a new option for efficient deployment, are designed to decrease human exposure to ABVs by releasing active ingredients into the air that disrupt mosquito–human contact. A parallel, cluster-randomized controlled trial was conducted in Iquitos, Peru, to quantify the impact of a transfluthrin-based spatial repellent on human ABV infection. From 2,907 households across 26 clusters (13 per arm), 1,578 participants were assessed for seroconversion (primary endpoint) by survival analysis. Incidence of acute disease was calculated among 16,683 participants (secondary endpoint). Adult mosquito collections were conducted to compare Ae. aegypti abundance, blood-fed rate, and parity status through mixed-effect difference-in-difference analyses. The spatial repellent significantly reduced ABV infection by 34.1% (one-sided 95% CI lower limit, 6.9%; one-sided P value = 0.0236, z = 1.98). Aedes aegypti abundance and blood-fed rates were significantly reduced by 28.6 (95% CI 24.1%, ∞); z = −9.11) and 12.4% (95% CI 4.2%, ∞); z = −2.43), respectively. Our trial provides conclusive statistical evidence from an appropriately powered, preplanned cluster-randomized controlled clinical trial of the impact of a chemical intervention, in this case a spatial repellent, to reduce the risk of ABV transmission compared to a placebo.Aedes-borne viral diseases (ABVDs) [e.g., dengue (DENV), chikungunya, Zika (ZIKV), and yellow fever] are devastating, expanding global public health threats that disproportionally affect low- and middle-income countries. DENV, one of the most rapidly increasing vector-borne infectious diseases, results in ∼400 million infections each year (1, 2), with 4 billion people at risk for infection annually (3). Currently, the primary means for ABVD prevention is controlling the primary mosquito vector, Aedes aegypti. Existing vector control interventions, however, have failed to prevent ABV transmission and epidemics (4–6).There is an urgent need to develop evidence-based guidance for the use of new and existing ABV vector control tools. The evidence base for vector control against ABVs is weak, despite considerable government investments in World Health Organization (WHO)-recommended control of larval habitats (larviciding, container removal) and ultra-low-volume insecticide spraying (4, 5, 7–9). These strategies continue to be implemented despite the lack of rigorously generated data from controlled clinical trials demonstrating they reduce ABV infection or disease (6). The only ABV intervention with a proven epidemiological impact in a cluster-randomized control trial (cRCT) assessed community mobilization to reduce mosquito larval habitats (10). A recent test-negative trial with Wolbachia-infected mosquitoes reported a significant reduction of DENV illness in Indonesia (11).Spatial repellents (SRs) are devices that contain volatile active ingredients that disperse in air. The active ingredients can repel mosquitoes from entering a treated space, inhibit attraction to human host cues, or disrupt mosquito biting and blood-feeding behavior and, thus, interfere with mosquito–human contact (12–14). Any of these outcomes reduce the probability of pathogen transmission. Pyrethroid-based SRs have shown efficacy in reducing malaria infections in China (15) and Indonesia (16). There have, however, been no clinical trials evaluating the protective efficacy (PE) of SRs against ABV infection or disease.To generate evidence for public health consideration, we conducted a double-blinded, parallel cRCT to demonstrate and quantify the PE of a transfluthrin-based SR to reduce ABV infection incidence over 2 y in a human cohort in Iquitos, Peru. 相似文献
106.
Nicole Frumento Alexis Figueroa Tingchang Wang Muhammad N. Zahid Shuyi Wang Guido Massaccesi Georgia Stavrakis James E. Crowe Jr Andrew I. Flyak Hongkai Ji Stuart C. Ray George M. Shaw Andrea L. Cox Justin R. Bailey 《The Journal of clinical investigation》2022,132(15)
A prophylactic hepatitis C virus (HCV) vaccine that elicits neutralizing antibodies could be key to HCV eradication. However, the genetic and antigenic properties of HCV envelope (E1E2) proteins capable of inducing anti-HCV broadly neutralizing antibodies (bNAbs) in humans have not been defined. Here, we investigated the development of bNAbs in longitudinal plasma of HCV-infected persons with persistent infection or spontaneous clearance of multiple reinfections. By measuring plasma antibody neutralization of a heterologous virus panel, we found that the breadth and potency of the antibody response increased upon exposure to multiple genetically distinct infections and with longer duration of viremia. Greater genetic divergence between infecting strains was not associated with enhanced neutralizing breadth. Rather, repeated exposure to antigenically related, antibody-sensitive E1E2s was associated with potent bNAb induction. These data reveal that a prime-boost vaccine strategy with genetically distinct, antibody-sensitive viruses is a promising approach to inducing potent bNAbs in humans. 相似文献
107.
108.
Neurotrophins regulate survival, neurite outgrowth, and phenotypic maturation of developing neurons. Brain-derived neurotrophic factor (BDNF) can promote the survival of developing cholinergic forebrain neurons in vitro and reduce their degeneration following injury in adult rats. We investigated the role of endogenous BDNF during postnatal development of these cholinergic neurons by analyzing homozygous BDNF-deficient (−/−) mice and their littermates (+/+, +/−). At P6, the number of choline acetyltransferase- (ChAT) positive neurons in the medial septum was 23% lower in BDNF−/− mice, although their brain and body weight was normal. At P15, control (+/+) littermates had 45% more and 45% larger ChAT-positive neurons and a much denser cholinergic hippocampal innervation than at P6, indicative of maturation of the septohippocampal system. In BDNF−/− mice, the number, size, and ChAT-immunostaining intensity of the cholinergic neurons remained the same between P6 and P15 (few mice survive longer). BDNF−/− mice had about three times more TUNEL-labeled (a marker of apoptosis) cells in the medial septum at P6, consistent with (but not proof of) the possibility that the cholinergic neurons were dying. The cholinergic hippocampal innervation in BDNF−/− mice expanded to a lesser extent than in controls and had reduced levels of acetylcholinesterase staining at P15. The developmental deficits were largely similar in the neostriatum of BDNF−/− mice. These findings suggest that BDNF is critical for postnatal development and maturation of cholinergic forebrain neurons. 相似文献
109.
Nicole E. Sharp Wendy J. Svetanoff Amita Desai Hanna Alemayehu Maneesha U. Raghavan Susan W. Sharp James C. Brown Douglas C. Rivard Shawn D. St. Peter George W. Holcomb III 《The Journal of surgical research》2014
Background
We have previously reported that children receive significantly less radiation exposure after abdominal and/or pelvis computed tomography (CT) scanning for acute appendicitis when performed at our children's hospital (CH) rather than at outside hospitals (OH). In this study, we compare the amount of radiation children receive from head CTs for trauma done at OH versus those at our CH.Methods
A retrospective chart review was performed on all children transferred to our hospital after receiving a head CT for trauma at an OH between July 2012 and December 2012. These children were then blindly case matched based on date, age, and gender to children at our CH.Results
There were 50 children who underwent head CT scans for trauma at 28 OH. There were 21 females and 29 males in each group. Average age was 7.01 ± 0.5 y at the OH and 7.14 ± 6.07 at our CH (P = 0.92). Average weight was 30.81 ± 4.69 kg at the OH and 32.69 ± 27.21 kg at our CH (P = 0.81). Radiation measures included dose length product (671.21 ± 22.6 mGycm at OH versus 786.28 ± 246.3 mGycm at CH, P = 0.11) and CT dose index (53.4 ± 2.26 mGy at OH versus 49.2 ± 12.94 mGy at CH, P = 0.56).Conclusions
There is no significant difference between radiation exposure secondary to head CTs for traumatic injuries performed at OH and those at a dedicated CH. 相似文献110.
Erwin Chiquete Jesus Alegre-Díaz Ana Ochoa-Guzmn Liz Nicole Toapanta-Yanchapaxi Carlos Gonzlez-Carballo Adrin Garcilazo-vila Rogelio Santacruz-Benitez Raúl Ramírez-Reyes Rosa María Wong-Chew Guadalupe Guerrero Max Schmulson Jaime Berumen Valeria Sandoval-Rodríguez Eduardo Ruiz-Ruiz Carlos Cantú-Brito 《Archives of Medical Science》2022,18(3):711