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   12144篇
  免费   1116篇
  国内免费   696篇
耳鼻咽喉   201篇
儿科学   188篇
妇产科学   163篇
基础医学   1699篇
口腔科学   108篇
临床医学   1544篇
内科学   2061篇
皮肤病学   132篇
神经病学   657篇
特种医学   423篇
外国民族医学   9篇
外科学   1282篇
综合类   1504篇
一般理论   1篇
预防医学   592篇
眼科学   317篇
药学   1173篇
  8篇
中国医学   549篇
肿瘤学   1345篇
  2024年   26篇
  2023年   200篇
  2022年   465篇
  2021年   570篇
  2020年   434篇
  2019年   440篇
  2018年   433篇
  2017年   358篇
  2016年   370篇
  2015年   579篇
  2014年   698篇
  2013年   666篇
  2012年   901篇
  2011年   926篇
  2010年   581篇
  2009年   481篇
  2008年   586篇
  2007年   597篇
  2006年   604篇
  2005年   573篇
  2004年   389篇
  2003年   370篇
  2002年   333篇
  2001年   250篇
  2000年   291篇
  1999年   321篇
  1998年   174篇
  1997年   196篇
  1996年   175篇
  1995年   139篇
  1994年   128篇
  1993年   84篇
  1992年   105篇
  1991年   65篇
  1990年   67篇
  1989年   63篇
  1988年   47篇
  1987年   48篇
  1986年   44篇
  1985年   23篇
  1984年   26篇
  1983年   25篇
  1982年   12篇
  1981年   14篇
  1979年   8篇
  1978年   6篇
  1977年   11篇
  1976年   10篇
  1974年   7篇
  1971年   6篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
Annals of Surgical Oncology - Management of axillary lymph nodes in breast cancer has undergone significant change over the past decade through landmark clinical trials. This study aimed to assess...  相似文献   
82.
PurposeTo investigate the clinical characteristics, chemosensitivity, and outcome of metastatic upper tract urothelial carcinoma (UTUC).Patients and MethodsRecords of patients with metastatic UTUC since January 2005 were retrieved from a database that included clinical and survival data. Statistical analyses including survival and multivariate analyses of factors were respectively performed by the Kaplan-Meier method and Cox proportional hazard model.ResultsA total of 250 consecutive UTUC cases were evaluated. There were 56 patients (22.4%) with initially diagnosed stage IV disease. The most common metastatic sites were lung (39.6%), distant lymph nodes (39.2%), bone (19.6%), liver (18.0%), and adrenal gland (7.2%), respectively, and the local recurrence rate was 10.4%. Two hundred thirteen patients received first-line chemotherapy. The overall response rate was only 28.7% and the median progression-free survival time was only 5.0 months. The overall survival time of the cohort was 18.0 months. Multivariate analyses showed that initially diagnosed stage IV disease, number of metastatic organs ≥3, no response to chemotherapy and cycles of chemotherapy ≤2 were adverse prognosticators for overall survival.ConclusionUTUC presented to be more prone to metastasize than locally recur and thought to have low chemosensitivity. Stage IV disease at initial diagnosis, number of metastatic organs, response and cycles of chemotherapy were independent prognosticators for metastatic UTUC.  相似文献   
83.
目的探讨如何利用CT表现对肾上腺隐匿型嗜铬细胞瘤和肾上腺皮质腺瘤进行鉴别诊断。方法收集2010年1月至2020年1月期间中国医科大学附属第一医院收治的177例肾上腺肿瘤患者进行回顾性分析,对比各组患者之间的一般临床资料和CT表现。结果隐匿型嗜铬细胞瘤56例、皮质醇腺瘤32例、醛固酮腺瘤44例、无功能腺瘤45例,隐匿型嗜铬细胞瘤组在肿瘤侧别上与无功能腺瘤组差异有统计学意义,在肿瘤最大直径、平扫CT值、动脉期和延迟期增强CT值上均显著大于三组肾上腺腺瘤组。以肿瘤直径≥2.95 cm诊断隐匿型嗜铬细胞瘤,曲线下面积(AUC)为0.872,敏感度为87.5%,特异性为76.0%;当平扫CT值≥24.5 Hu时,AUC为0.929,敏感度为94.0%,特异性为82.5%;当动脉期增强CT值≥89.5 Hu时,AUC为0.886,敏感度为72.7%,特异性为90.6%;当延迟期增强CT值≥82.5 Hu时,AUC为0.937,敏感度为84.6%,特异性为95.3%;联合以上四个指标时,AUC为0.981,阈值为≥0.118,敏感度为100%,特异性为90.6%。结论以肿瘤直径2.95 cm、平扫CT值24.5 Hu、动脉期增强CT值89.5 Hu和延迟期增强CT值82.5 Hu为阈值对肾上腺隐匿型嗜铬细胞瘤有较好的鉴别诊断价值。  相似文献   
84.
A pseudotumor appearance of the liver has not been previously described in chronic hepatitis. We reviewed 81 charts with a biopsy diagnosis of "chronic hepatitis" and at least one radiologic liver scan, and found four cases with a pseudotumor appearance. They all had features on radiologic scans suggestive of space-occupying lesions. Histology showed chronic hepatitis in all four. Two were cirrhotic, one due to alcohol and the other due to hepatitis B. The other two patients had chronic active hepatitis with regenerative nodules but only limited fibrosis, one due to hepatitis B, the other probable non-A, non-B. None had any evidence of hepatic malignancy. We conclude that some patients with chronic hepatitis may present with a pseudotumor appearance on radiological scans, due to the presence of regenerative nodules. Space-occupying lesions on liver scans in chronic hepatitis may represent non-neoplastic liver disease.  相似文献   
85.
OBJECTIVE: To establish an animal model of mitochondrial DNA (mtDNA) deletion and investigate the possible role of mtDNA deletion in aminoglycoside antibiotic induced deafness. METHODS: Thirty wistar rats (4 months) were randomly divided into group A and B. Doxorubicin (DOX) was subcutaneously injected at doses of 2 mg/kg twice per week for 3 months in group A and then kanamycin (KM) was intraperitoneally injected 500 mg/kg per day for 10 consecutive days. The treatments of group B were identical to group A, except normal saline was substituted for DOX. The thresholds of auditory brainstem response (ABR) were measured before and after the drug administrations. The inner ear membranous labyrinthine tissue was harvested and mtDNA was amplified to identify 4,834 bp deletion by PCR technique. RESULTS: The elevation of the mean ABR thresholds in group A(67.08 +/- 8.59) dB peSPL was significantly higher than that in group B (12.71 +/- 4.42) dB peSPL after KM administration (P < 0.001). In group A, 9 of the 15 rats demonstrated 4,834 bp mtDNA deletion. However, mtDNA 4,834 bp deletion was negative in group B animals. CONCLUSION: DOX can induce mtDNA deletion in the inner ear tissue of the rat. mtDNA deletion in the inner ear may play an important role in the hypersensitivity to aminoglycoside antibiotic ototoxicity.  相似文献   
86.
铅对大鼠肠道神经元和血管平滑肌细胞NOS活性的影响   总被引:12,自引:0,他引:12  
用β-NADPH组织化学方法研究铅对大鼠肠壁肌间神经佾内神经元和血管平滑肌一氧化氮合酶(NOS)活性的影响。结果发现:腹腔注射醋酸铅(40mg.kg^-1)15d后,大鼠肠道NOS阳性神经无元和阳性纤维数量减少,且阳性神经元的形态也有不同程度的改变,肠壁内血管平滑肌NOS活性下降。上述变化提示NO的生成减少可能是铅中毒时腹能的机制之一。  相似文献   
87.
为观察坐位颈椎不同位置时椎管内结构的变化,解剖颈椎标本8具。用灌石蜡的方法测量颈椎矢状径及截面积的变化。结果:颈椎轻度屈曲时,椎间盘、黄韧带、椎板、硬膜、脊髓的形态与位置发生变化,但对椎管容积影响不大,中立位和自然屈颈位时椎管矢状径和椎管截面积两者均无明显差异(p>0.05)。提示:颈椎后路椎板成形椎管扩大手术时,坐位是值得推荐的一种体位。  相似文献   
88.
本文报导了自1981年-1993年对杭州→香港中国民航航班及港龙航空公司航班,九大类供机食品卫生监督检验结果及分析.按不同年份,各类食品,不同检验项目以及不同航空公司配餐食品卫生质量分别作了比较.共检供机食品969份,合格535份,不合格434份,总合格率为55.21%.不同食品的合格率比较,合格率最高的是糕点为75.22%,其次为面饭为74.32%,合格率最低的是色拉为11.11%.  相似文献   
89.
目的:探讨退变性腰椎管狭窄症的手术治疗。方法:对94例60岁以上患者进行分型和手术治疗。结果:将本病分为Ⅰ型(侧隐窝狭窄型);Ⅱ型(中央管狭窄型);Ⅲ型(混合型)。对Ⅰ型手术方式采用单侧或双侧椎板开窗,扩大神经根管或(和)摘除髓核;对Ⅱ型行半椎板或全椎板切除术;对Ⅲ型行全椎板切除术。结论:通过术后疗效观察和3年随访,根据分型的不同选择不同的手术方式,可达到较好的临床疗效  相似文献   
90.
The authors examined potential associations between air-pollution exposures and respiratory symptoms and illnesses of 4,108 adults who resided in 4 districts of 3 large, distinct Chinese cities. Data on respiratory health outcomes and relevant risk factors for parents and children were obtained via standardized questionnaires in the winter of 1988. (The effects in children were described previously.) The yearly averages of ambient levels of total suspended particles in the 4 districts for the years 1985-1988 differed greatly. The authors constructed logistic-regression models to assess the respiratory health parameters of parents of the children. The results revealed significant and strong effects, by district, on prevalence rates of cough, phlegm, persistent cough and phlegm, and wheeze for both the mothers and the fathers. In addition, the odds ratios increased as ambient total suspended particle concentration increased across the 3 urban districts. Other local within-city risk factors, however, may have confounded the total suspended particles-effects association, especially for asthma prevalence. Findings for adults were similar to those found for their children. A strong adverse effect of active tobacco smoking on the fathers' respiratory health was observed. The children appeared to be more strongly affected by passive smoking exposure received in their homes than their mothers.  相似文献   
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