全文获取类型
收费全文 | 56361篇 |
免费 | 4369篇 |
国内免费 | 1875篇 |
专业分类
耳鼻咽喉 | 447篇 |
儿科学 | 1235篇 |
妇产科学 | 2192篇 |
基础医学 | 6366篇 |
口腔科学 | 1167篇 |
临床医学 | 4798篇 |
内科学 | 6036篇 |
皮肤病学 | 792篇 |
神经病学 | 3804篇 |
特种医学 | 1598篇 |
外国民族医学 | 7篇 |
外科学 | 4220篇 |
综合类 | 8794篇 |
现状与发展 | 3篇 |
一般理论 | 6篇 |
预防医学 | 5111篇 |
眼科学 | 1667篇 |
药学 | 7020篇 |
85篇 | |
中国医学 | 4702篇 |
肿瘤学 | 2555篇 |
出版年
2023年 | 802篇 |
2022年 | 1073篇 |
2021年 | 1943篇 |
2020年 | 1903篇 |
2019年 | 1883篇 |
2018年 | 1794篇 |
2017年 | 1787篇 |
2016年 | 1795篇 |
2015年 | 1722篇 |
2014年 | 3259篇 |
2013年 | 4194篇 |
2012年 | 3275篇 |
2011年 | 3633篇 |
2010年 | 2904篇 |
2009年 | 2632篇 |
2008年 | 2592篇 |
2007年 | 2631篇 |
2006年 | 2352篇 |
2005年 | 2114篇 |
2004年 | 1813篇 |
2003年 | 1771篇 |
2002年 | 1344篇 |
2001年 | 1292篇 |
2000年 | 1036篇 |
1999年 | 963篇 |
1998年 | 740篇 |
1997年 | 719篇 |
1996年 | 663篇 |
1995年 | 773篇 |
1994年 | 656篇 |
1993年 | 551篇 |
1992年 | 509篇 |
1991年 | 453篇 |
1990年 | 475篇 |
1989年 | 401篇 |
1988年 | 292篇 |
1987年 | 257篇 |
1986年 | 318篇 |
1985年 | 435篇 |
1984年 | 416篇 |
1983年 | 255篇 |
1982年 | 332篇 |
1981年 | 266篇 |
1980年 | 286篇 |
1979年 | 211篇 |
1978年 | 176篇 |
1977年 | 166篇 |
1976年 | 154篇 |
1975年 | 111篇 |
1974年 | 90篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
《Vaccine》2019,37(22):2952-2959
CD8+ T cells are known to control infections, but their role in preventing latent infection from establishing has not been thoroughly investigated.We hypothesized that a potent CD8+ T cell response patrolling the mucosal viral entry points could kill the first infected cells and thereby abrogate the infection before latency is established.To investigate this, replication deficient adenovirus serotype 5 vectors encoding murine γ-herpesvirus-68 CD8+ T cell epitopes linked to the T cell adjuvant Invariant chain, were developed. We show that intranasal vaccination of mice reduces the risk of establishment of latent infection from multiple intranasal ID50 challenges with murine γ-herpesvirus-68 by 81% per exposure at 14 days post vaccination. Protection waned over time, but immune responses were extended by heterologous prime-boost vaccination applied simultaneously intramuscularly and intranasally, and animals vaccinated 66 days prior to challenge showed a strong trend of long-term protection.Our data provides evidence that CD8+ T cells are able to protect against establishment of latent infection. Although the protective efficacy is difficult to maintain over time, this proof-of-concept study suggests a role for a CD8+ T cell arm in future vaccine strategies against latent human viral infections caused by pathogens such as HIV and multiple herpes virus. 相似文献
62.
Multiple opioids are known to trigger mast cell degranulation. We report the case of a neonate with blistering skin lesions at birth who died of multi‐organ failure after administration of morphine. Given the excessive histamine release and potential complications associated with morphine administration, alternative opioids and adjuvants should be considered in infants presenting with evidence of bullous or infiltrative skin lesions until mastocytosis is ruled out. 相似文献
63.
Objectives:To reassess the long-term camouflage effects of resin infiltration (Icon, DMG, Hamburg, Germany) of white spot lesions (WSL) and sound adjacent enamel (SAE) achieved in a previous trial. The null hypothesis was tested that there were no significantly different CIE-L*a*b*-ΔE-values between WSL and SAE areas of assessment after at least 24 months (T24) compared to those at baseline (T0).Materials and Methods:Of twenty subjects who received previous resin infiltration treatment of nteeth = 111 nonrestored, noncavitated postorthodontic WSL after multibracket treatment during a randomized controlled trial and were contacted 20 months after baseline, eight subjects (trial teeth nteeth = 40; m/f ratio 1/7; age range (mean; SD) 12–17 [15.25; 2.12] years); response rate: 40%) were available for follow-up after at least 24 months (T24). CIE-L*a*b* differences between summarized color and lightness values (ΔEWSL/SAE) of WSL and SAE were assessed using a spectrophotometer and compared to baseline data assessed prior to infiltration (T0), and those after 6 (T6), and 12 (T12) months using paired t tests at a significance level of α = 5%.Results:T24 assessments were performed after a mean 33.86 (SD: 8.64; Min: 24; Max: 45) months following T0. Mean (SD) ΔEWSL/SAE units of available teeth were 8.76 (5.33) at baseline; 5.5 (2.75) at T6; 5.2 (2.41) at T12; and 5.57 (2.6) at T24. Comparisons of T6, T12, and T24 with T0 yielded highly significant differences, whereas T6–T24 and T12–T24 differences were found to be not significant.Conclusions:Assimilation of infiltrated WSL to the color of adjacent enamel by resin infiltration is considered to be suitable for the long-term improvement in the esthetic appearance of postorthodontic WSL. 相似文献
64.
Tatiana Elghossain Sarah Bott Chaza Akik Hala Ghattas Carla Makhlouf Obermeyer 《The Journal of adolescent health》2019,64(1):8-19
Purpose
This article presents a systematic review of the prevalence of violence against adolescents in the 22 countries of the Arab League.Methods
Data on physical and emotional child maltreatment, sexual abuse, bullying and fighting, violence in schools, and intimate partner violence against adolescent girls were retrieved using: (1) a systematic search for peer-reviewed journal articles using Medline and the Social Sciences Citation Index; and (2) a search for nationally-representative, population-based surveys.Results
Published evidence suggests that physical, sexual, and emotional violence against adolescents is widespread in the Arab region. In many studies, prevalence rates exceeded other regional or global estimates, including rates of violent discipline, fighting, and intimate partner violence against adolescent girls. Data on certain forms of violence (e.g. violent discipline) are available from many Arab countries; but data on other forms, e.g., sexual abuse, are scarce. Most peer-reviewed journal articles are based on small studies with diverse operational definitions and methods, making comparisons challenging.Conclusions
High rates of violence against adolescents in the region merit greater attention from policy makers concerned with determinants of adolescent health. There is also a need to expand and improve the quality of quantitative and qualitative research on violence against adolescents in the region. 相似文献65.
《Clinical lung cancer》2019,20(4):e421-e429
BackgroundDetection of ALK and ROS1 gene rearrangements in non–small-cell lung cancer is required for directing patient care. Although fluorescence in situ hybridization (FISH) and immunohistochemistry have been established as gold standard methods, next-generation sequencing (NGS) platforms are called to be at least equally successful. Comparison of these methods for translation into daily use is currently under investigation.Patients and MethodsForty non–small-cell lung cancer paraffin-embedded samples with previous ALK (n = 33) and ROS1 (n = 7) FISH results were examined with the Oncomine Focus Assay and tested for ALK and ROS1 immunoreactivity. Clinical implications of concurrent molecular alterations and concordance between methods were evaluated.ResultsNGS was successful in 32 (80%) cases: 25 ALK and 7 ROS1. Few concomitant alterations were detected: 1 ALK rearranged case had an ALK p.L1196M-resistant mutation, 4 had CDK4, MYC, and/or ALK amplifications, and 1 ROS1 rearranged case showed a FGFR4 amplification. Comparison between techniques revealed 5 (16%) discordant cases that had lower progression-free survival than concordant cases: 7.6 (95% confidence interval, 2.2-13) versus 19.4 (95% confidence interval, 10.1-28.6). Remarkably, 4 of these cases had isolated 3' signal FISH pattern (P = .026).ConclusionOur data support that the identification of 3' isolated signal FISH pattern in ALK and ROS1 cases might suggest a false-positive result. NGS seems a reliable technique to assess ALK and ROS1 rearrangements, offering the advantage over immunohistochemistry of detecting other molecular alterations with potential therapeutic implications. 相似文献
66.
Xinran Wang Ying Jia Huiyan Deng Yao Liu Yueping Liu 《Pathology, research and practice》2019,215(2):308-314
Recent studies have shown that intratumoral heterogeneity is prevalent in esophageal squamous cell cancer (ESCC) based on DNA sequencing and chromosome analysis in multiple regions from the same tumor. This study aimed to investigate the expression of ZNF750, EP300, MTOR and KMT2D and their intratumoral heterogeneity (ITH) in patients with ESCC. A total of 106 cases, who underwent esophagectomy from 2008 to 2010, with two foci from each case, were tested by immunohistochemistry(IHC) as well as 12 cases were tested by RNAscope in this study.We found that 58/106 (54.72%), 66/106 (62.26%), 75/106 (70.75%%) of ESCC showed high expression of ZNF750, EP300, MTOR, respectively by IHC, and 8/12 (66.67%), 10/12 (83.33%), 4/12 (33.33%) and 6/12 (50%) showed high expression of ZNF750, EP300, MTOR and KMT2D, respectively by RNAscope. Multivariate analysis showed that MTOR expression was an independent infavorable prognostic factor of overall survival (OS) (HR?=?1.921; P?=?0.000). This study also found that 44/106(4151%), 37/106 (34.91%), 39/106(36.79%) of ESCC showed heterogeneous expression of ZNF750, EP300 and MTOR respectively by IHC, 8/12(66.67%), 8/12(66.67%), 4/12(33.33%), 4/12(33.33%) of ZNF750, EP300, MTOR and KMT2D respectively by RNAscope, IHC and RNAscope could successfully detect a high prevalence of ITH. In conclusion, findings of this study showed that ZNF750, EP300, MTOR and KMT2D heterogeneously expressed in ESCC. High expression of ZNF750 related to a better outcome, while EP300 and MTOR related to a poor prognosis. 相似文献
67.
68.
《European journal of surgical oncology》2020,46(3):363-368
As global life expectancy has increased in most countries, there is a rising percentage of patients over 65 years old being diagnosed with colorectal cancer. Despite an increase in the incidence and prevalence of colorectal cancer in older adults, this cohort receives adjuvant therapy at a decreased rate due to anticipated intolerance. The presumed limitations seem to be based on chronologic age, competing life limiting diagnoses, and the paucity of data studying this population in major clinical trials. This review explores the data regarding disparities in the treatment of older patients with colorectal cancer, safety and efficacy of adjuvant therapy, and newer tools to make decisions based on the biologic age, rather than chronologic age, of the patient. 相似文献
69.
70.
Positron emission tomography (PET)‐based staging of regional amyloid deposition has recently emerged as a promising tool for sensitive detection and stratification of pathology progression in Alzheimer's Disease (AD). Here we present an updated methodological framework for PET‐based amyloid staging using region–specific amyloid‐positivity thresholds and assess its longitudinal validity using serial PET acquisitions. We defined region‐specific thresholds of amyloid‐positivity based on Florbetapir‐PET data of 13 young healthy individuals (age ≤ 45y), applied these thresholds to Florbetapir‐PET data of 179 cognitively normal older individuals to estimate a regional amyloid staging model, and tested this model in a larger sample of patients with mild cognitive impairment (N = 403) and AD dementia (N = 85). 2‐year follow‐up Florbetapir‐PET scans from a subset of this sample (N = 436) were used to assess the longitudinal validity of the cross‐sectional model based on individual stage transitions and data‐driven longitudinal trajectory modeling. Results show a remarkable congruence between cross‐sectionally estimated and longitudinally modeled trajectories of amyloid accumulation, beginning in anterior temporal areas, followed by frontal and medial parietal areas, the remaining associative neocortex, and finally primary sensory‐motor areas and subcortical regions. Over 98% of individual amyloid deposition profiles and longitudinal stage transitions adhered to this staging scheme of regional pathology progression, which was further supported by corresponding changes in cerebrospinal fluid biomarkers. In conclusion, we provide a methodological refinement and longitudinal validation of PET‐based staging of regional amyloid accumulation, which may help improving early detection and in‐vivo stratification of pathologic disease progression in AD. 相似文献