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   5809篇
  免费   619篇
  国内免费   116篇
耳鼻咽喉   25篇
儿科学   100篇
妇产科学   64篇
基础医学   831篇
口腔科学   41篇
临床医学   521篇
内科学   1209篇
皮肤病学   166篇
神经病学   290篇
特种医学   178篇
外国民族医学   2篇
外科学   386篇
综合类   866篇
现状与发展   1篇
预防医学   266篇
眼科学   65篇
药学   328篇
  4篇
中国医学   219篇
肿瘤学   982篇
  2024年   34篇
  2023年   162篇
  2022年   253篇
  2021年   352篇
  2020年   284篇
  2019年   262篇
  2018年   235篇
  2017年   232篇
  2016年   233篇
  2015年   282篇
  2014年   429篇
  2013年   382篇
  2012年   358篇
  2011年   336篇
  2010年   269篇
  2009年   248篇
  2008年   241篇
  2007年   260篇
  2006年   203篇
  2005年   180篇
  2004年   154篇
  2003年   156篇
  2002年   125篇
  2001年   124篇
  2000年   80篇
  1999年   73篇
  1998年   67篇
  1997年   56篇
  1996年   64篇
  1995年   53篇
  1994年   59篇
  1993年   31篇
  1992年   41篇
  1991年   30篇
  1990年   17篇
  1989年   23篇
  1988年   12篇
  1987年   17篇
  1986年   19篇
  1985年   29篇
  1984年   23篇
  1983年   12篇
  1982年   12篇
  1981年   8篇
  1980年   7篇
  1979年   3篇
  1978年   3篇
  1977年   3篇
  1975年   2篇
  1973年   3篇
排序方式: 共有6544条查询结果,搜索用时 15 毫秒
31.
With the application of liver transplantation for patients with biliary atresia (BA), we have had the opportunity to review the clinicopathologic features of the native livers from 10 transplanted BA patients. A single large nodule at porta hepatis (hilar nodule) was noted in three of 10 patients, and an ill-defined nodule-like lesion at porta hepatis was present in two other patients. The three BA patients with hilar nodules were long-term survivors, compared to the patients with nodule-like and those without nodules. The hilar nodules measured between 5.0 cm and 8.0 cm and histologically, they were partly surrounded by fibrous septa with relatively well-preserved liver architectures and fewer inflammatory cells at the portal triads when compared to the surrounding cirrhotic lesions. No nuclear or cellular atypia was observed. Proliferating cell nuclear antigen labeling index was higher in the surrounding cirrhotic lesions than the hilar nodules. The nodule-like lesions at porta hepatis also showed similar light microscopic and immunohistochemical features as the hilar nodules. These hilar nodules did not seem to contain any malignant potential. The benign histology with relatively well-preserved liver architecture and the preferential site of occurrence at porta hepatis where bile seemed to flow more smoothly, suggested possible residues of less-affected hepatic tissues.  相似文献   
32.
Pearson syndrome (PS) is a multisystem mitochondrial respiratory chain disorder typically characterized by sideroblastic anemia and exocrine pancreatic insufficiency. PS is caused by a single large‐scale mitochondrial DNA (mtDNA) deletion. PS classically presents in the first year of life and may be fatal in infancy. Children who survive PS may progress to develop Kearns–Sayre syndrome later in life. The full phenotypic spectrum and prognosis of the condition continue to evolve. Here we report five new patients with PS with unique clinical presentations, including four patients with onset later than previously reported in the literature, and one patient with prenatal onset of symptoms. The timing and unique features of these presentations support an expanded phenotypic spectrum of single large‐scale mtDNA deletion syndromes (SLSMDS) and reinforce the importance of including SLSMDS in the differential for children with complex multisystem presentations.  相似文献   
33.
Chiu KC  Fine M  Ikle D  Slovak ML  Arber DA 《Human pathology》2003,34(12):1259-1264
Cell proliferation may be evaluated by various methods, including Ki-67 immunohistochemistry and measures of telomerase activity. Both methods would theoretically show comparable increases in a given case. To evaluate the relationship between these 2 markers of proliferation in aggressive mature B-cell lymphomas, 48 cases were studied. The study group included 5 cases of mantle cell lymphoma (MCL); 6 cases of Burkitt's/Burkitt's-like lymphoma (BL); 9 cases of follicular lymphoma, grade 3 (FLC); and 28 cases of diffuse large B-cell lymphoma (DLC). Telomerase activity was measured as total product generated (TPG) units, and TPG results for the aforementioned cases were compared to the TPG results for 10 cases of reactive follicular hyperplasia. An overlap in TPG scores between reactive cases and lymphoma cases was found. Significant differences in both log TPG (P = 0.0443) and Ki-67 (P = 0.0006) were seen in the different lymphoma types. A positive correlation between Ki-67 percentage and TPG score was identified in FLC (r = 0.9281; P = 0.0003), but a poor correlation between these 2 indicators was seen in the other lymphoma types. Cluster analysis identified distinct patterns for MCL, FLC, and BL, but heterogeneous patterns for DLC. Because increases in both Ki-67 proliferation and telomerase activity are reported in normal germinal centers (GCs), these tests were also evaluated for usefulness as markers of a GC cell phenotype. Among the FLC and DLC cases, features of a GC phenotype significantly correlated with increased Ki-67 percentage (P = 0.0152), but not with increased log TPG. An elevated log TPG correlated with CD10 expression, and elevated Ki-67 percentage correlated with both CD10 and BCL-6 expression. TPG level and Ki-67 percentage did not correlate with the presence of t(14;18) or BCL-2 protein expression. Although the proliferation patterns were fairly distinctive for MCL, FLC, and BL, these studies show that markers of cell proliferation do not by themselves,identify distinct subtypes of large cell lymphomas. With the exception of FLC, the tumors exhibited poor correlation between telomerase activity and Ki-67 proliferation index. These tests did show some correlation with expression of GC cell phenotypic markers, however.  相似文献   
34.
BACKGROUND: Tumor segment resection is one of the standard methods for the treatment of bone tumors. However, the reconstruction of bone defects atumor resection faces many challenges. A growing number of researchers are focusing on 3D-printed prostheses for bone defect repair and reconstruction following bone tumor surgery. OBJECTIVE: To explore the feasibility of 3D-printed prostheses in the reconstruction of large bone defect following bone tumor surgery and to evaluate the postoperative outcomes. METHODS: Retrospective analysis of clinical data of 24 patients [19 males and 5 females, age 23.8 (6-61) years] who underwent bone tumor resection and 3D-printed prosthesis implantation in the Department of Bone Oncology, the First Affiliated Hospital of Xinjiang Medical University from December 2020 to September 2021 was conducted. There were 7 cases with distal femur tumor, 5 with pelvis tumor, 4 with proximal tibia tumor, 3 with middle femur tumor, 1 with distal tibia tumor, 1 with proximal humerus tumor, 1 with middle humerus tumor, 1 with scapula tumor, 1 with ulna tumor, and 22 cases with primary tumors (13 osteosarcoma, 4 Ewing sarcoma, 2 giant cell tumor of bone, 1 chondroblastoma, 1 chondrosarcoma, and 1 osteoblastoma), 2 metastatic carcinoma. Preoperative and postoperative imaging data were recorded and neoadjuvant chemotherapy was administered in 17 cases before surgery. The Musculoskeletal Tumour Society score was used to assess limb function before surgery and 6 months after surgery, and pain was assessed by the Visual Analog Scale, as well as the complications were recorded. RESULTS AND CONCLUSION: (1) All patients undergoing resection of the tumor segment and 3D-printed prosthesis implantation for the reconstruction of the bone defect were followed for 6-49 months, and the results showed that the length of osteotomy was (18.2 ± 7.3) cm and an average intraoperative bleeding volume was 740 (100-3 000) mL. (2) Two patients died of systemic metastasis, the remaining 22 had no pulmonary metastasis or recurrence during the follow-up period, and 1 patient developed aseptic loosening of the prosthesis at 25 months postoperatively. (3) The Musculoskeletal Tumour Society scores were significantly increased, while Visual Analog Scale scores were significantly decreased (P < 0.05) at 6 months postoperatively. (4) The Musculoskeletal Tumor Society score was rated excellent in all 22 patients at the final follow-up. (5) These results suggest that 3D-printed prosthesis is suitable for the reconstruction of large bone defects caused by bone tumor resection. Patients have good postoperative function and few complications. However, further investigations are needed to explore long-term follow-up results. © 2023, Publishing House of Chinese Journal of Tissue Engineering Research. All rights reserved.  相似文献   
35.
The purpose of the present paper was to examine the level of apoptosis and the relationships among apoptosis, apoptosis-associated proteins, and proliferating potential in lymphoma tissues to clarify the characteristics of apoptosis in diffuse large B-cell lymphomas (DLBCL) of the central nervous system (CNS). The formalin-fixed, paraffin-embedded tissues of CNS and non-CNS DLBCL (20 cases each) were studied by terminal deoxynucleotidyl transferase-mediated dUTP-nick end labeling (TUNEL) and immunohistochemistry, using antibodies against single-stranded DNA (ssDNA), cleaved caspase-3, bcl-2, bax, p53, Fas and Ki-67. The cleaved caspase-3 immunohistochemistry detected apoptosis of the lymphoma cells most sensitively compared to TUNEL and ssDNA immunohistochemistry. High expression (grade + + or + + +) of cleaved caspase-3 was found more frequently in CNS DLBCL (11 cases, 55%) than non-CNS DLBCL (three cases, 15%; P = 0.009). Bax-positivity of lymphoma cells was increased in six cases of CNS DLBCL, which also showed high positivity of cleaved caspase-3. There was no significant correlation between the cleaved caspase-3-positivity and the Ki-67 positivity. The present study indicates that the number of apoptotic cells and expression level of cleaved caspase-3 were significantly higher in CNS DLBCL than non-CNS DLBCL, and that the correlation of bax and cleaved caspase-3 expression was often present in CNS DLBCL.  相似文献   
36.
Summary Large coronary arteries of the dog were contracted with 5-hydroxytryptamine (5-HT). The 5-HT2-receptor antagonist ketanserin antagonized the 5-HT-induced effects. Unlike Brazenor and Angus (Europ J Pharmacol 81: 569–576, 1982), who reported insurmountable antagonism of the effects of 5-HT in dog coronaries, we found that the antagonism by ketanserin can be surmounted, provided the concentrations of 5-HT are high enough. Ketanserin also unmasked a saturable component of the 5-HT-induced contractions. Although ketanserin (0.1–1 mol/l) depressed the maximal force of the saturable component, it did not change its EC50 (-log mol/l 8.0). We conclude that large coronary arteries of dog are contracted by 5-HT mainly though 5-HT2-receptors and to a smaller extent through receptors different from 5-HT2.  相似文献   
37.
<正> 为了解决运动员在剧烈运动中出现的口咽部干燥,灼热感,避免因口干而喝水过多引起一系列副作用。我们和广州白云山制药厂合作,共同研制微型饮料——“利喉乐”。于1985起应用于体育、文艺、教育等部门,取得了良好的效果。现将“利喉乐”的配方,剂型、包装,药理、毒理以及临床观察总结如下:  相似文献   
38.
总结支气管动脉栓塞(BAE)治疗大咯血 84例,即时止血 78例,5例咯血明显减少,有效率 98.8%(83/84),1例止血无效。无严重并发症发生。认为(BAE)是目前治疗大咯血安全有效的治疗方法。  相似文献   
39.
目的 :探讨自攻自断螺纹钉在大面积缺损牙保存性修复中的应用。方法 :采用自攻自断螺纹钉 ,选择凡因龋坏或者外伤使牙体组织损失残缺过大、牙髓未露、活力正常的牙进行修复。结果 :本组 5 0例经自攻自断螺纹钉进行固位修复 ,5年后随访 42例 ,除 2例因上颌磨牙牙尖折断而不能修复拔除外 ,其它 40例均达到评判标准 ,总成功率达 95 %。结论 :自攻自断螺纹钉主要用于对严重缺损而牙髓健康的牙进行保存性修复 ,还可对要做壳冠修复的牙进行牙壁加固。该方法因材料来源方便 ,临床效果显著 ,值得推广。  相似文献   
40.
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