全文获取类型
收费全文 | 47350篇 |
免费 | 3276篇 |
国内免费 | 591篇 |
专业分类
耳鼻咽喉 | 857篇 |
儿科学 | 851篇 |
妇产科学 | 1081篇 |
基础医学 | 6785篇 |
口腔科学 | 818篇 |
临床医学 | 4064篇 |
内科学 | 10565篇 |
皮肤病学 | 1582篇 |
神经病学 | 3109篇 |
特种医学 | 2395篇 |
外科学 | 6806篇 |
综合类 | 686篇 |
现状与发展 | 1篇 |
一般理论 | 18篇 |
预防医学 | 1936篇 |
眼科学 | 1230篇 |
药学 | 4007篇 |
中国医学 | 525篇 |
肿瘤学 | 3901篇 |
出版年
2023年 | 317篇 |
2022年 | 844篇 |
2021年 | 1459篇 |
2020年 | 708篇 |
2019年 | 1141篇 |
2018年 | 1417篇 |
2017年 | 1022篇 |
2016年 | 1327篇 |
2015年 | 1780篇 |
2014年 | 2244篇 |
2013年 | 2496篇 |
2012年 | 3727篇 |
2011年 | 3728篇 |
2010年 | 2262篇 |
2009年 | 1893篇 |
2008年 | 2808篇 |
2007年 | 2667篇 |
2006年 | 2463篇 |
2005年 | 2376篇 |
2004年 | 2006篇 |
2003年 | 1855篇 |
2002年 | 1689篇 |
2001年 | 1183篇 |
2000年 | 1070篇 |
1999年 | 957篇 |
1998年 | 376篇 |
1997年 | 326篇 |
1996年 | 298篇 |
1995年 | 247篇 |
1994年 | 212篇 |
1993年 | 137篇 |
1992年 | 429篇 |
1991年 | 337篇 |
1990年 | 368篇 |
1989年 | 326篇 |
1988年 | 304篇 |
1987年 | 268篇 |
1986年 | 235篇 |
1985年 | 215篇 |
1984年 | 174篇 |
1983年 | 134篇 |
1982年 | 96篇 |
1981年 | 93篇 |
1980年 | 92篇 |
1979年 | 156篇 |
1978年 | 98篇 |
1977年 | 98篇 |
1975年 | 84篇 |
1974年 | 83篇 |
1972年 | 81篇 |
排序方式: 共有10000条查询结果,搜索用时 15 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.
Comprehensive evidence regarding the treatment of non-anaemic iron deficiency in patients undergoing valvular heart surgery is lacking. This study aimed to investigate the association between non-anaemic iron deficiency and postoperative outcomes in these patients. We retrospectively analysed 321 patients of which 180 (56%) had iron deficiency (defined as serum ferritin < 100 ng.ml-1 or < 300 ng.ml-1 with transferrin saturation < 20%). While the iron-deficient group had lower pre-operative haemoglobin levels than the non-iron deficient group (median (IQR [range]) 134 (127–141 [120–172]) g.l-1, 143 (133–150 [120–179]) g.l-1, p = 0.001), there was no between-group difference in allogeneic red blood cell transfusion. Median (IQR [range]) days alive and out of hospital at postoperative day 90 was 1 day shorter in the iron-deficient group (80 (77–82 [9–85]) days vs. 81 (79–83 [0–85]) days, p = 0.026). In multivariable analysis, only cardiopulmonary bypass duration (p = 0.032) and intra-operative allogeneic red blood cell transfusion (p = 0.011) were significantly associated with reduced days alive and out of hospital at postoperative day 90. Iron deficiency did not exert any adverse influence on secondary outcomes except length of hospital stay. Our findings indicate that non-anaemic iron deficiency alone is not associated with adverse effects in patients undergoing valvular heart surgery when it does not translate into an increased risk of allogeneic transfusion. 相似文献
3.
4.
Hyun Jong Choi Jong Ho Moon Yun Nah Lee Hyun Su Kim Ji Su Ha Tae Hoon Lee Sang‐Woo Cha Young Deok Cho Sang‐Heum Park 《Digestive endoscopy》2015,27(7):772-775
Direct peroral cholangioscopy (POC) using an ultra‐slim upper endoscope is one modality of POC for intraductal endoscopic evaluation and treatment of the bile duct. Choledochoduodenostomy (CDS) is one modality of biliary bypass surgery that provides a new route to the bile duct. We carried out direct POC using an ultra‐slim upper endoscope without the use of accessories in 10 patients (four sump syndromes, three bile duct strictures and three intrahepatic duct stones) previously undergoing surgical CDS. Direct POC was successful in all patients. The use of an intraductal balloon catheter was required in one patient for advancement of the endoscope into the bile duct. Distal bile ducts with sump syndromes were cleared using baskets and water irrigation under direct POC. Cholangiocarcinoma was diagnosed in one patient with hilar bile duct stricture after cholangioscopic evaluation and a targeting forceps biopsy under direct POC. Intrahepatic duct stones were successfully extracted after intraductal fragmentation under direct POC. Oozing bleeding occurred during intraductal lithotripsy but stopped spontaneously. Direct POC using an ultra‐slim upper endoscope without the assistance of accessories can easily be carried out in patients undergoing CDS. 相似文献
5.
Jae Yun Ahn Jung Bae Park Sungbae Moon Jae Wan Cho Dong Ho Park 《Ophthalmic epidemiology》2020,27(2):105-114
ABSTRACT
Purpose
Work-related eye injuries have been reported with a variety of epidemiologic and clinical characteristics. We aimed to identify epidemiologic characteristics of work-related eye injuries and risk factors associated with severe injury in a large metropolitan city. 相似文献6.
7.
A mixed‐method study of effects of a therapeutic play intervention for children on parental anxiety and parents' perceptions of the intervention
下载免费PDF全文
![点击此处可从《Journal of advanced nursing》网站下载免费的PDF全文](/ch/ext_images/free.gif)
8.
目的:探讨甲状旁腺激素(PTH)对大鼠牵张成骨(DO)过程中ONC、OPN、C-FOS、COL1、VEGF、RUNX2、ALP基因表达的影响。方法30只雄性大鼠制备大鼠下颌骨DO模型。随机分5组,每组6只。第1组(只有牵张无PTH),术后8周取材,应用HE染色及微CT检测,以确定成骨情况。第2组(有牵张无PTH),第3组(有牵张有PTH),第4组(无牵张有PTH),第5组(对照组:无牵张无PTH)。2、3、4组及对照组术后1周取材,RT-PCR测定ONC、OPN、C-FOS、COL1、VEGF、RUNX2、ALP基因的表达。结果第1组,新骨形成,骨质充满牵张区,骨质连续,大鼠建模成功。RT-PCR检测结果显示,2、3、4组与对照组比较,OPN、COL1、RUNX2、ALP基因表达有明显提高(P<0.05),其中第3组最为明显。ONC、C-FOS、VEGF基因2、3、4组与对照组比较差异无统计学意义(P>0.05)。结论 PTH在 DO 过程中,间歇性给以 PTH的作用只有在牵张期发挥作用,其对 OPN、COL1、RUNX2、ALP基因表达能够获得理想的协同作用。 相似文献
9.
Psoriasis is a chronic, inflammatory, immune‐mediated disease. Approximately 30% of patients have disease onset before age 18 years. Psoriasis in children and adolescents may be difficult to control, with subsequent poor quality of life and psychosocial consequences. We describe the case of a 12‐year‐old boy with severe, refractory, chronic plaque psoriasis for 6 years. Various therapeutic regimens including different topical corticosteroids, topical vitamin D analogs, phototherapy, photochemotherapy, systemic therapy with methotrexate, cyclosporin, and combination therapies showed only partial or transient responses with frequent relapses. Because anti‐interleukin‐12/23 agents have been successfully used in adults with psoriasis, ustekinumab was initiated and our patient showed a rapid, excellent, sustained response. No recurrence or flares have been observed after 33 months of follow‐up. This case illustrates that ustekinumab may be an effective and safe therapeutic option in adolescents with psoriasis. 相似文献
10.
PNPLA3 gene polymorphism and response to lifestyle modification in patients with nonalcoholic fatty liver disease
下载免费PDF全文
![点击此处可从《Journal of gastroenterology and hepatology》网站下载免费的PDF全文](/ch/ext_images/free.gif)