全文获取类型
收费全文 | 4004篇 |
免费 | 232篇 |
国内免费 | 35篇 |
专业分类
耳鼻咽喉 | 32篇 |
儿科学 | 109篇 |
妇产科学 | 78篇 |
基础医学 | 441篇 |
口腔科学 | 134篇 |
临床医学 | 295篇 |
内科学 | 810篇 |
皮肤病学 | 131篇 |
神经病学 | 99篇 |
特种医学 | 288篇 |
外国民族医学 | 4篇 |
外科学 | 737篇 |
综合类 | 192篇 |
一般理论 | 2篇 |
预防医学 | 301篇 |
眼科学 | 79篇 |
药学 | 303篇 |
中国医学 | 15篇 |
肿瘤学 | 221篇 |
出版年
2023年 | 37篇 |
2022年 | 130篇 |
2021年 | 212篇 |
2020年 | 104篇 |
2019年 | 136篇 |
2018年 | 148篇 |
2017年 | 98篇 |
2016年 | 120篇 |
2015年 | 148篇 |
2014年 | 192篇 |
2013年 | 210篇 |
2012年 | 280篇 |
2011年 | 324篇 |
2010年 | 218篇 |
2009年 | 187篇 |
2008年 | 240篇 |
2007年 | 232篇 |
2006年 | 193篇 |
2005年 | 153篇 |
2004年 | 128篇 |
2003年 | 145篇 |
2002年 | 109篇 |
2001年 | 35篇 |
2000年 | 30篇 |
1999年 | 36篇 |
1998年 | 55篇 |
1997年 | 44篇 |
1996年 | 43篇 |
1995年 | 24篇 |
1994年 | 30篇 |
1993年 | 24篇 |
1992年 | 9篇 |
1991年 | 11篇 |
1990年 | 9篇 |
1989年 | 14篇 |
1988年 | 17篇 |
1987年 | 28篇 |
1986年 | 10篇 |
1985年 | 12篇 |
1984年 | 8篇 |
1983年 | 7篇 |
1982年 | 15篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1978年 | 8篇 |
1977年 | 4篇 |
1976年 | 15篇 |
1975年 | 6篇 |
1972年 | 3篇 |
1969年 | 3篇 |
排序方式: 共有4271条查询结果,搜索用时 232 毫秒
1.
2.
Khaled Adil Marija Popovic Fabio L. Cury Sergio L. Faria Marie Duclos Luis Souhami 《Practical radiation oncology》2019,9(1):24-28
Purpose
This study aimed to investigate 3 planning target volume (PTV) margin expansions and determine the most appropriate volume to be used in bladder preservation therapy when using daily cone beam computed tomography (CBCT). We aimed to establish whether a smaller PTV expansion is feasible without risking geographical miss.Methods and materials
The study included patients with bladder cancer who were treated with a hypofractionated course of radiation therapy delivered with intensity modulated radiation therapy. The clinical target volume (CTV) was the whole empty bladder, and the PTV consisted of a 1.5-cm margin around the bladder (PTV1.5 cm). Patients underwent daily CBCT imaging before treatment to assess the bladder volume and ensure accurate positioning. We investigated 2 additional smaller PTV margin expansions to determine the most appropriate volume to be used with CBCT as a daily image guided radiation therapy modality. These margins were created retrospectively on every CBCT. The first additional volume was a uniform PTV margin of the surrounding 1 cm (PTV1 cm). When considering that the majority of the internal bladder movement was due to the variation in filling that occurs in the superior and anterior directions, a second volume of an anisotropic PTV margin with a 1.5-cm superior/anterior and 1 cm in other directions (PTV1/1.5 cm) was created. We recorded the frequency and measured the volume of bladder falling out of each PTV based on the daily CBCT.Results
For the purpose of this study, we considered an arbitrary 5 cm3 of CTV falling out of the designated PTV as a clinically significant volumetric miss. The frequency of such a miss when applying the uniform PTV1 cm was 1%. However, when applying the uniform PTV1.5 cm and anisotropic PTV1/1.5 cm margins, the frequency was 0.5% and 0.5%, respectively.Conclusions
The anisotropic PTV expansion of 1.5 cm superiorly and anteriorly and 1 cm in all other directions around the bladder (CTV) provides a safe PTV approach when daily CBCT imaging is used to localize an empty bladder. 相似文献3.
4.
5.
6.
7.
Vincent Laville Sigrid Le Clerc Khaled Ezzedine Randa Jdid Lieng Taing Toufik Labib Cdric Coulonges Damien Ulveling Pilar Galan Christiane Guinot Leopold Fezeu Frdrique Morizot Julie Latreille Denis Malvy Erwin Tschachler Jean‐Franois Zagury 《Experimental dermatology》2019,28(8):892-898
Sagging eyelid is considered as an outward of skin ageing and may cause medical issues. However, little is known about the factors involved in sagging eyelid. The study, which aims at determining genetic risk factors for eyelid sagging, was conducted in a cohort of 502 unrelated Caucasian women living in the Paris region. All included participants were aged between 44 and 70 years old (mean age, 57.6 years old). The severity of sagging eyelid was graded in 6 categories by a dermatologist using standardized photographs of the face. A genome wide association study adjusted on potential risk factors (including age and smoking habits) was conducted to identify genetic associations. Two single nucleotide polymorphisms in total linkage disequilibrium on chromosome 10, rs16927253 (P = 7.07 × 10‐10) and rs4746957 (P = 1.06 × 10‐8), were significantly associated with eyelid sagging severity. The rs16927253‐T and rs4746957‐A alleles showed a dominant protective effect towards eyelid sagging. These polymorphisms are located in intronic parts of the H2AFY2 gene which encodes a member of the H2A histone family and very close to the AIFM2 gene that induces apoptosis. Additionally, single nucleotide polymorphisms with a false discovery rate below 0.25 were located nearby the type XIII collagen COL13A1 gene on chromosome 10 and in the ADAMTS18 gene on chromosome 16. Several relevant genes were identified by the genome wide association study for their potential role in the sagging eyelid severity. 相似文献
8.
Akira Sawaki Nobumasa Mizuno Kuniyuki Takahashi Tsuneya Nakamura Masahiro Tajika Hiroki Kawai Toshifumi Isaka Hiroshi Imaoka Yasuyuki Okamoto Masatoshi Aoki Hiroyuki Inoue Ahmed AS Salem Yasushi Yatabe Kenji Yamao 《Digestive endoscopy》2006,18(1):40-44
Background: Gastrointestinal stromal tumors (GIST) are one of the most common mesenchymal tumors of the gastrointestinal tract. GIST are defined by positive immunohistochemical staining for KIT or CD34 and thus are generally diagnosed after surgery. Because small GIST are rarely diagnosed before surgery, the clinical course of these small tumors is not clear. The aim of the present study was to follow changes in size and configuration of small GIST that were pathologically confirmed using endoscopic ultrasonography‐guided fine‐needle aspiration biopsy (EUS‐FNAB). Methods: Between July 1997 and December 2003, 16 tumors in 16 patients (10 men and 6 women) with an immunohistochemical diagnosis of GIST were regularly followed in our hospital. The median patient age when EUS‐FNAB was performed was 62 years (range 26–82 years) and the median follow‐up period was 4.9 years (range 0.5–9.6 years). Results: Fourteen tumors showed no remarkable changes in size and shape during follow up compared with the initial diagnosis. Two tumors enlarged: one tumor approximately doubled its diameter in 8 years and the other tumor increased from 1.8 cm at diagnosis to up to 10 cm after only 2 years. Doubling time of the latter tumor was calculated as 3.1 months. Conclusions: We conclude that EUS‐FNAB might be a good modality for final diagnosis of GIST without surgery, and that GIST without rapid growth on follow up can be endoscopically followed. 相似文献
9.
10.
Coronary artery bypass grafts: visualization with MR imaging 总被引:1,自引:0,他引:1