全文获取类型
收费全文 | 33633篇 |
免费 | 2273篇 |
国内免费 | 98篇 |
专业分类
耳鼻咽喉 | 498篇 |
儿科学 | 830篇 |
妇产科学 | 476篇 |
基础医学 | 4056篇 |
口腔科学 | 454篇 |
临床医学 | 3686篇 |
内科学 | 6806篇 |
皮肤病学 | 424篇 |
神经病学 | 2943篇 |
特种医学 | 1381篇 |
外科学 | 5671篇 |
综合类 | 388篇 |
一般理论 | 40篇 |
预防医学 | 2986篇 |
眼科学 | 523篇 |
药学 | 2543篇 |
中国医学 | 30篇 |
肿瘤学 | 2269篇 |
出版年
2023年 | 223篇 |
2022年 | 182篇 |
2021年 | 988篇 |
2020年 | 638篇 |
2019年 | 978篇 |
2018年 | 1174篇 |
2017年 | 818篇 |
2016年 | 825篇 |
2015年 | 986篇 |
2014年 | 1477篇 |
2013年 | 1945篇 |
2012年 | 2802篇 |
2011年 | 2873篇 |
2010年 | 1506篇 |
2009年 | 1393篇 |
2008年 | 2401篇 |
2007年 | 2362篇 |
2006年 | 2159篇 |
2005年 | 2178篇 |
2004年 | 2051篇 |
2003年 | 1833篇 |
2002年 | 1688篇 |
2001年 | 185篇 |
2000年 | 169篇 |
1999年 | 205篇 |
1998年 | 266篇 |
1997年 | 194篇 |
1996年 | 192篇 |
1995年 | 157篇 |
1994年 | 161篇 |
1993年 | 133篇 |
1992年 | 79篇 |
1991年 | 76篇 |
1990年 | 67篇 |
1989年 | 63篇 |
1988年 | 51篇 |
1987年 | 41篇 |
1986年 | 32篇 |
1985年 | 37篇 |
1984年 | 50篇 |
1983年 | 55篇 |
1982年 | 68篇 |
1981年 | 44篇 |
1980年 | 32篇 |
1979年 | 21篇 |
1978年 | 20篇 |
1977年 | 19篇 |
1976年 | 12篇 |
1975年 | 13篇 |
1974年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
1.
Kevin Kyung Ho Choi Santosh Sanagapalli 《World journal of gastrointestinal oncology》2022,14(3):568-586
Barrett's esophagus (BE) is the precursor to esophageal adenocarcinoma (EAC). Progression to cancer typically occurs in a stepwise fashion through worsening dysplasia and ultimately, invasive neoplasia. Established EAC with deep involvement of the esophageal wall and/or metastatic disease is invariably associated with poor long-term survival rates. This guides the rationale of surveillance of Barrett’s in an attempt to treat lesions at an earlier, and potentially curative stage. The last two decades have seen a paradigm shift in management of Barrett’s with rapid expansion in the role of endoscopic eradication therapy (EET) for management of dysplastic and early neoplastic BE, and there have been substantial changes to international consensus guidelines for management of early BE based on evolving evidence. This review aims to assist the physician in the therapeutic decision-making process with patients by comprehensive review and summary of literature surrounding natural history of Barrett’s by histological stage, and the effectiveness of interventions in attenuating the risk posed by its natural history. Key findings were as follows. Non-dysplastic Barrett’s is associated with extremely low risk of progression, and interventions cannot be justified. The annual risk of cancer progression in low grade dysplasia is between 1%-3%; EET can be offered though evidence for its benefit remains confined to highly select settings. High-grade dysplasia progresses to cancer in 5%-10% per year; EET is similarly effective to and less morbid than surgery and should be routinely performed for this indication. Risk of nodal metastases in intramucosal cancer is 2%-4%, which is comparable to operative mortality rate, so EET is usually preferred. Submucosal cancer is associated with nodal metastases in 14%-41% hence surgery remains standard of care, except for select situations. 相似文献
2.
3.
4.
5.
6.
7.
Objectives
We explored levonorgestrel (LNG) concentrations, bleeding patterns and endometrial thickness in women with epilepsy (WWE) initiating an LNG-intrauterine device (IUD) co-administered with antiepileptic drugs (AEDs).Study design
This pilot study included 20 WWE ages 18 to 45 years with well-controlled seizures and stable AED regimens initiating a 52-mg LNG-IUD (20 mcg/d initial release). We collected blood and measured endometrial thickness before IUD placement and 21 days, 3 months and 6 months thereafter. Participants recorded bleeding/spotting daily. We measured total LNG (radioimmunoassay), serum hormone binding globulin (SHBG, immunoassay) and calculated the free LNG index. We compared total LNG, free LNG index, SHBG and endometrial thickness over time using a linear mixed-effects model.Results
Total LNG, free LNG index and SBHG levels remained stable from day 21 throughout. Endometrial thickness decreased from a median of 5.9 mm [interquartile range (IQR) 4.6–7.5] at day 21 to 3.3mm (2.8–4.9) by month 6 (p=0.02). Bleeding and spotting days decreased from a median of 16 (IQR 13–23) in month 1 to 6.5 (IQR 4–8.5) in month 6 regardless of AED regimen.Conclusion
Like women without epilepsy, WWE initiating the LNG-IUD experience stable total LNG concentrations and decreasing endometrial thickness and bleeding over the first 6 months of use.Implications
Like women without epilepsy, WWE using antiepileptic drugs can expect a stable LNG concentration and decreasing bleeding during the first 6 months of LNG-IUD use. Our data can be useful for guidance of WWE considering use the LNG-IUD. 相似文献8.
Background
Though the optimal treatment regimen in older patients with glioblastoma multiforme (GBM) remains to be established, multiple randomized studies have supported the use of hypofractionated (1–3?weeks) versus traditional regimens (6?weeks). Here we examine hypofractionated regimen practice patterns among older patients with GBM.Methods
We used the National Cancer Database and included individuals aged ≥65?years with GBM diagnosed from 2005 to 2014 undergoing biopsy/resection followed by chemotherapy and radiation initiated ≤8-weeks of diagnosis. We defined traditional fractionation as ≤200?cGy and hypofractionation as >200?cGy. We compared patient characteristics using a chi-squared test and multivariable logistic regression. We compared 90-day mortality rates following initiation of radiation using the Wald statistic in propensity score matched cohorts.Results
The final cohort included 14,931 individuals with 1524 undergoing hypofractionated treatment. From 2005 to 2014 hypofractionated utilization rates were 7%, 9%, 13%, and 18% among those 65–69, 70–74, 75–79, and ≥80?years of age, respectively. Patients treated at an academic/research center had a >60% increased odds (OR, 1.61; 95% CI, 1.43–1.81) of undergoing hypofractionated regimens versus a community center. Ninety-day mortality rates were high in both groups (hypofractionated: 32%; traditional: 24%; p?<?.001).Conclusions
The majority of older GBM patients do not undergo hypofractionated radiation. High 90-day mortality in both groups suggests that hypofractionation may improve the survival-to-treatment time ratio and positively impact patient quality of life. Hypofractionated radiation regimens for GBM should be discussed with older patients and considered for inclusion in efforts to improve the quality and value of cancer care. 相似文献9.
James H. Holmes Michael J. Schurr Booker T. King Kevin Foster Lee D. Faucher Mary A. Lokuta Allen R. Comer Peggy J. Rooney Kelly F. Barbeau Stuart T. Mohoney Angela L.F. Gibson B. Lynn Allen-Hoffmann 《Burns : journal of the International Society for Burn Injuries》2019,45(8):1749-1758
ObjectiveThis open-label, controlled, randomized study assessed the safety, tolerability, and efficacy of StrataGraft tissue compared to autograft in the treatment of deep partial-thickness (DPT) burns.MethodsThirty subjects with DPT thermal burns (3%–43% total body surface area) were treated with StrataGraft tissue as follows: cohort 1, ≤220 cm2 refrigerated tissue; cohort 2, ≤440 cm2 refrigerated tissue; and cohort 3, ≤440 cm2 cryopreserved tissue. On each subject, two comparable areas of DPT burn were randomized to receive StrataGraft tissue or autograft. Coprimary end points were the percent area of the StrataGraft tissue treatment site undergoing salvage autografting by Day 28 and wound closure of treatment sites by 3 months.ResultsBy Day 28, no StrataGraft tissue treatment sites underwent autografting. By 3 months, 93% and 100% of the StrataGraft tissue and autograft treatment sites achieved complete wound closure, respectively. No significant differences in observer total and overall opinion POSAS scores between StrataGraft tissue and autograft treatment sites were observed at any timepoint. The most common adverse event was pruritus (17%).ConclusionsStrataGraft tissue treatment of DPT thermal burns reduced the need for autograft, resulted in wound closure and treatment-site cosmesis comparable to that of autograft, and was well tolerated. 相似文献