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   30291篇
  免费   3383篇
  国内免费   800篇
耳鼻咽喉   165篇
儿科学   512篇
妇产科学   1273篇
基础医学   2151篇
口腔科学   898篇
临床医学   8089篇
内科学   4144篇
皮肤病学   429篇
神经病学   1135篇
特种医学   1832篇
外国民族医学   6篇
外科学   3217篇
综合类   4790篇
现状与发展   3篇
预防医学   1318篇
眼科学   753篇
药学   1837篇
  52篇
中国医学   483篇
肿瘤学   1387篇
  2024年   119篇
  2023年   608篇
  2022年   1137篇
  2021年   1394篇
  2020年   1630篇
  2019年   1409篇
  2018年   1349篇
  2017年   1363篇
  2016年   1335篇
  2015年   1364篇
  2014年   2308篇
  2013年   2211篇
  2012年   1594篇
  2011年   1759篇
  2010年   1376篇
  2009年   1290篇
  2008年   1372篇
  2007年   1398篇
  2006年   1151篇
  2005年   985篇
  2004年   864篇
  2003年   825篇
  2002年   677篇
  2001年   573篇
  2000年   480篇
  1999年   453篇
  1998年   400篇
  1997年   370篇
  1996年   308篇
  1995年   293篇
  1994年   246篇
  1993年   220篇
  1992年   195篇
  1991年   179篇
  1990年   147篇
  1989年   115篇
  1988年   111篇
  1987年   90篇
  1986年   105篇
  1985年   138篇
  1984年   115篇
  1983年   60篇
  1982年   96篇
  1981年   61篇
  1980年   55篇
  1979年   47篇
  1978年   32篇
  1977年   23篇
  1976年   15篇
  1975年   11篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
Radiologic evaluation of the skeleton and scanning electron microscopic studies of the teeth were performed on an infant boy with a lethal osteogenesis imperfecta (OI) syndrome who died at 10 mo of pneumonia. The skeletal findings included ribs that were focally expanded by fracture calluses, flat vertebral bodies, and wide limb bones. On fractured tooth surfaces, the enamel and dentin were normal as was the dentin calcification front. Although microscopic abnormalities have been noted in teeth from previously reported infants with lethal OI, a few studies also report infants with normal teeth. These differences in dental findings may indicate heterogeneity in OI lethal in infancy. Results of our study indicate that, until the primary biochemical defects in the OI syndromes are elucidated, examination of teeth from other infants with lethal OI and detailed evaluation of other clinical and skeletal features will aid in delineating heterogeneity and variation in expression in lethal OI.  相似文献   
42.
目的 探讨二维超声对原发性肾病综合征预后的判断价值。方法 根据临床检查结果将 12 0例原发性肾病综合征患者分为 3组 ,并与二维超声检查结果进行相关性分析。结果 完全缓解组的肾脏超声检查结果与对照组比较无显著性差异 (P >0 .0 5 ) ,部分缓解组的肾脏超声检查结果与对照组比较有显著性差异 (P <0 .0 5 ) ,无效组的肾脏超声检查结果与对照组比较有非常显著性差异 (P <0 .0 1)。结论 二维超声检查原发性肾病综合征患者的肾脏无异常时预后良好 ,而肾脏缩小越明显 ,肾皮质回声越强 ,则预后越差。  相似文献   
43.
目的 :探讨高脂血症红细胞形态变化和临床意义。方法 :Wistar大鼠分为正常对照组 ( NC)和高脂血症组 ( HL,喂饲高脂饲料 ) ,利用扫描电镜观察红细胞形态改变并计数分类。结果 :与 NC组比较 ,HL组的正常红细胞百分比由 76.4 %减少到 4 5.7%、棘型红细胞、球口型红细胞、靶型红细胞分别由4 %、2 .2 %、1.5%增加到 17.3%、10 .4 %、5.8% ,嵴型和其它异型红细胞也略有增加。结论 :高脂血症的异型红细胞明显增加。  相似文献   
44.
Polyorchidism is usually diagnosed incidentally when the patient undergoes imaging or surgery for some other reason. Although we are facing lack of evidence in different steps of diagnostic and therapeutic workup of these patients, this disorder is usually considered benign, not requiring any intervention. We report the case of a man complaining of a palpable mass in his scrotum. We evaluated the patient using ultrasound, MRI and serum tumour marker level measurement. The patient was finally diagnosed with polyorchidism (three testes). For the management, we recommended annual physical examination, US examination and serum tumour marker level measurement.  相似文献   
45.
BackgroundTo diagnose periprosthetic joint infection (PJI) preoperatively, ultrasound-guided joint aspiration (US-JA) may not be performed when effusion is minimal or absent. We aimed to report and investigate the diagnostic performance of ultrasound-guided periprosthetic biopsy (US-PB) of synovial tissue to obtain joint samples in patients without fluid around the implants.MethodsOne-hundred nine patients (55 men; mean age: 68 ± 13 years) with failed total hip arthroplasty (THA) who underwent revision surgery performed preoperative US-JA or US-PB to rule out PJI.ResultsSixty-nine of 109 patients had joint effusion and underwent US-JA, while the remaining 40 with dry joint required US-PB. Thirty-five of 109 patients (32.1%) had PJI, while 74/109 (67.9%) had aseptic THA failure. No immediate complications were observed in both groups. Technical success of US-PB was 100%, as the procedure was carried on as planned in all cases. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of US-JA were 52.2%, 97.8%, 92.3%, 80.3%, and 82.6%, while for US-PB, they were 41.7%, 100%, 100%, 80%, and 82.5%, respectively, with no significant difference (P = .779). Using the final diagnosis as reference standard, we observed a moderate agreement with both US-JA (k = 0.56) and US-PB (k = 0.50).ConclusionWe present a novel US-guided technique to biopsy periprosthetic synovial tissue of failed THA to rule out PJI. We found similar diagnostic performance as compared with traditional US-JA. This supports future larger studies on this procedure that might be applied in patients without joint effusion.  相似文献   
46.
IntroductionA fast and cheap method of skin assessment in systemic sclerosis (SSc) is an area of extensive research. Established in 1979, the Rodnan skin score is a palpation-based method used among clinicians. This method has some limitations, such as: examiner’s skills, subjective results, and no standardization. In the last few years researchers have been exploring ultrasound-based techniques as a possible tool for skin assessment among patients with SSc. The aim of the study is to develop a protocol of elastography-based skin imaging evaluation among patients with SSc.Material and methodsReview of the literature and own experience.ResultsProposition of elastography-based skin imaging protocol among patients with SSc.ConclusionsThe authors present a potential protocol of ultrasound-based examination of skin involvement among patients with SSc.  相似文献   
47.
48.
对200例大肠癌旁“移行粘膜”进行了粘液组化HID/AB及PAT/KOH/PAS检测,单克隆抗体MC3和CEA免疫组化标记,凝集素PNA、UEA-1及DBA受体测定,扫描电镜观察。其结果与10例正常直肠粘膜、130例癌组织、155例各型腺瘤型息肉及3-5个月胎儿大肠粘膜进行对照。结果表明大肠粘膜从良性到恶性的各阶段粘液组化及免疫组化的改变有显著差异(P<0.05或P<0.01),癌旁“移行粘膜”也存在类似癌及胎儿大肠的不成熟性病理变化,异常范围88.0%的病例在2-3cm以内。  相似文献   
49.
A rat model has been developed to compare relative morphological changes in the nasal mucosa after exposure to potential membrane permeation enhancers. Scanning electron microscopy was used to characterize gross structural and specific cellular changes following exposure. Micrographs of the rat nasal mucosa were scored in four categories: (1) mucosal surface integrity, (2) ciliary morphology, (3) mucus/extracellular debris, and (4) presence of red blood cells. The order of increasing morphological damage resulting from a 5-min exposure to each surfactant was 0.5% Solulan C-24 0.5% Solulan C-24/0.5% sodium tauro-24,25-dihydrofusidate (STDHF) < 0.5% STDHF < 1.0% STDHF 1.0% Laureth-9 < 1.0% sodium taurodeoxycholate 1.0% sodium deoxycholate. The changes observed in the mucosal morphology after exposure to the various surfactants are in general agreement with data in the literature. This model is able to compare rapidly the relative morphological effects on the mucosal membrane of different nasal formulations.  相似文献   
50.
目的:用定量超声方法对有骨折史的骨质疏松症患者进行骨量检查,方法用CUBA Clinical型定量骨密度超声仪对393例被疑为骨质疏松的患者进行检测,并根据病史按有无骨折中进行分组。分析二组患者宽频超声衰减(BUA)、超声速率(VOS)、强度指数(SI)与骨折次数的关系。结果:伴有骨折史的骨质疏松症虱的BUA、VOS、SI值都要比无骨折史的患者明显降低(P=0.000)。结论定量超声值与骨折的发生次数呈负相关,其测定值越低,骨折的发生次数越多;骨的质量下降是造成骨质疏松骨折的主要原因。  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