首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   303760篇
  免费   25685篇
  国内免费   9217篇
耳鼻咽喉   3587篇
儿科学   6435篇
妇产科学   4345篇
基础医学   24305篇
口腔科学   8166篇
临床医学   27872篇
内科学   40922篇
皮肤病学   2946篇
神经病学   13193篇
特种医学   8957篇
外国民族医学   33篇
外科学   31831篇
综合类   50755篇
现状与发展   28篇
一般理论   28篇
预防医学   34738篇
眼科学   2890篇
药学   29162篇
  454篇
中国医学   34202篇
肿瘤学   13813篇
  2024年   1267篇
  2023年   5972篇
  2022年   10964篇
  2021年   14266篇
  2020年   13894篇
  2019年   14843篇
  2018年   13364篇
  2017年   12026篇
  2016年   11422篇
  2015年   10545篇
  2014年   20219篇
  2013年   20243篇
  2012年   17914篇
  2011年   19833篇
  2010年   16317篇
  2009年   13939篇
  2008年   13093篇
  2007年   13399篇
  2006年   11957篇
  2005年   10062篇
  2004年   8203篇
  2003年   7221篇
  2002年   5706篇
  2001年   4908篇
  2000年   4247篇
  1999年   3515篇
  1998年   2977篇
  1997年   2672篇
  1996年   2247篇
  1995年   2137篇
  1994年   1961篇
  1993年   1664篇
  1992年   1541篇
  1991年   1360篇
  1990年   1196篇
  1989年   1129篇
  1988年   1060篇
  1987年   930篇
  1986年   857篇
  1985年   2285篇
  1984年   2563篇
  1983年   1642篇
  1982年   2130篇
  1981年   1562篇
  1980年   1386篇
  1979年   1243篇
  1978年   1032篇
  1977年   815篇
  1976年   905篇
  1975年   594篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Background/PurposeA small number of Hirschsprung disease (HD) patients develop inflammatory bowel disease (IBD)-like symptoms after pullthrough surgery. The etiology and pathophysiology of Hirschsprung-associated IBD (HD-IBD) remains unknown. This study aims to further characterize HD-IBD, to identify potential risk factors and to evaluate response to treatment in a large group of patients.MethodsRetrospective study of patients diagnosed with IBD after pullthrough surgery between 2000 and 2021 at 17 institutions. Data regarding clinical presentation and course of HD and IBD were reviewed. Effectiveness of medical therapy for IBD was recorded using a Likert scale.ResultsThere were 55 patients (78% male). 50% (n = 28) had long segment disease. Hirschsprung-associated enterocolitis (HAEC) was reported in 68% (n = 36). Ten patients (18%) had Trisomy 21. IBD was diagnosed after age 5 in 63% (n = 34). IBD presentation consisted of colonic or small bowel inflammation resembling IBD in 69% (n = 38), unexplained or persistent fistula in 18% (n = 10) and unexplained HAEC >5 years old or unresponsive to standard treatment in 13% (n = 7). Biological agents were the most effective (80%) medications. A third of patients required a surgical procedure for IBD.ConclusionMore than half of the patients were diagnosed with HD-IBD after 5 years old. Long segment disease, HAEC after pull through operation and trisomy 21 may represent risk factors for this condition. Investigation for possible IBD should be considered in children with unexplained fistulae, HAEC beyond the age of 5 or unresponsive to standard therapy, and symptoms suggestive of IBD. Biological agents were the most effective medical treatment.Level of EvidenceLevel 4  相似文献   
2.
3.
穴位埋线是长效针灸,是在传统针具和针法基础上建立和发展起来的,是针灸技术的发展和延伸,穴位埋线的核心技术是穿刺技术,穴位埋线的三大要素中,针具、埋藏物、穿刺技巧之间是互相影响、互相促进的。针具的改进成功实现了穴位埋线疗法的第一次飞跃,埋藏物的改进成功实现了穴位埋线疗法的第二次飞跃,穿刺技术的改进和创新是穴位埋线疗法的第三次飞跃。  相似文献   
4.
We report two British cases of liver abscess, due to Klebsiella pneumoniae and associated with synchronous infection elsewhere, which required liver resection for definitive treatment. They illustrate the geographic spread of aggressive K pneumoniae liver infection and demonstrate the importance of early aggressive treatment.  相似文献   
5.
6.
Central illustration: cumulative major adverse cardiac events (MACE) and bioresorbable vascular scaffold (BVS) thrombosis rates after 1, 2, 3, 4 and 5 years.
  相似文献   
7.
目的:探讨健康干预应用于肥胖中学生的效果。方法:抽取张掖市第一中学肥胖中学生180例,随机分为观察组与对照组,观察组实施健康干预,对照组仅予以常规健康教育,比较两组肥胖改善情况。结果:观察组干预效果显著优于对照组(P<0.05);干预后观察组的 BMI、腰围、胸围及皮脂厚度均较对照组显著降低(P<0.05)。结论:在肥胖中学生中实施健康干预有利于促进学生身体形态生长水平的改善,控制和降低学生 BMI和肥胖增长速度。  相似文献   
8.
Antibody-mediated rejection is a major complication in renal transplantation. The pathologic manifestations of acute antibody-mediated rejection that has progressed to functional impairment of a renal transplant have been defined in clinical biopsy specimens. However, the initial stages of the process are difficult to resolve with the unavoidable variables of clinical studies. We devised a model of renal transplantation to elucidate the initial stages of humoral rejection. Kidneys were orthotopically allografted to immunodeficient mice. After perioperative inflammation subsided, donor-specific alloantibodies were passively transferred to the recipient. Within 1 hour after a single transfer of antibodies, C4d was deposited diffusely on capillaries, and von Willebrand factor released from endothelial cells coated intravascular platelet aggregates. Platelet-transported inflammatory mediators platelet factor 4 and serotonin accumulated in the graft at 100- to 1000-fold higher concentrations compared with other platelet-transported chemokines. Activated platelets that expressed P-selectin attached to vascular endothelium and macrophages. These intragraft inflammatory changes were accompanied by evidence of acute endothelial injury. Repeated transfers of alloantibodies over 1 week sustained high levels of platelet factor 4 and serotonin. Platelet depletion decreased platelet mediators and altered the accumulation of macrophages. These data indicate that platelets augment early inflammation in response to donor-specific antibodies and that platelet-derived mediators may be markers of evolving alloantibody responses.  相似文献   
9.
PurposeThe purpose of this study was to determine whether computed tomography (CT)-based machine learning of radiomics features could help distinguish autoimmune pancreatitis (AIP) from pancreatic ductal adenocarcinoma (PDAC).Materials and MethodsEighty-nine patients with AIP (65 men, 24 women; mean age, 59.7 ± 13.9 [SD] years; range: 21–83 years) and 93 patients with PDAC (68 men, 25 women; mean age, 60.1 ± 12.3 [SD] years; range: 36–86 years) were retrospectively included. All patients had dedicated dual-phase pancreatic protocol CT between 2004 and 2018. Thin-slice images (0.75/0.5 mm thickness/increment) were compared with thick-slices images (3 or 5 mm thickness/increment). Pancreatic regions involved by PDAC or AIP (areas of enlargement, altered enhancement, effacement of pancreatic duct) as well as uninvolved parenchyma were segmented as three-dimensional volumes. Four hundred and thirty-one radiomics features were extracted and a random forest was used to distinguish AIP from PDAC. CT data of 60 AIP and 60 PDAC patients were used for training and those of 29 AIP and 33 PDAC independent patients were used for testing.ResultsThe pancreas was diffusely involved in 37 (37/89; 41.6%) patients with AIP and not diffusely in 52 (52/89; 58.4%) patients. Using machine learning, 95.2% (59/62; 95% confidence interval [CI]: 89.8–100%), 83.9% (52:67; 95% CI: 74.7–93.0%) and 77.4% (48/62; 95% CI: 67.0–87.8%) of the 62 test patients were correctly classified as either having PDAC or AIP with thin-slice venous phase, thin-slice arterial phase, and thick-slice venous phase CT, respectively. Three of the 29 patients with AIP (3/29; 10.3%) were incorrectly classified as having PDAC but all 33 patients with PDAC (33/33; 100%) were correctly classified with thin-slice venous phase with 89.7% sensitivity (26/29; 95% CI: 78.6–100%) and 100% specificity (33/33; 95% CI: 93–100%) for the diagnosis of AIP, 95.2% accuracy (59/62; 95% CI: 89.8–100%) and area under the curve of 0.975 (95% CI: 0.936–1.0).ConclusionsRadiomic features help differentiate AIP from PDAC with an overall accuracy of 95.2%.  相似文献   
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号