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   417144篇
  免费   29574篇
  国内免费   5776篇
耳鼻咽喉   5628篇
儿科学   8656篇
妇产科学   10641篇
基础医学   56908篇
口腔科学   12465篇
临床医学   35112篇
内科学   83218篇
皮肤病学   8976篇
神经病学   28678篇
特种医学   15452篇
外国民族医学   97篇
外科学   64469篇
综合类   18459篇
现状与发展   19篇
一般理论   69篇
预防医学   20965篇
眼科学   10359篇
药学   35547篇
  50篇
中国医学   4896篇
肿瘤学   31830篇
  2021年   4162篇
  2020年   3162篇
  2019年   4056篇
  2018年   5885篇
  2017年   4874篇
  2016年   4764篇
  2015年   5913篇
  2014年   8038篇
  2013年   9794篇
  2012年   13240篇
  2011年   13556篇
  2010年   8680篇
  2009年   7963篇
  2008年   11781篇
  2007年   12645篇
  2006年   12389篇
  2005年   11297篇
  2004年   10557篇
  2003年   10534篇
  2002年   9900篇
  2001年   29581篇
  2000年   29652篇
  1999年   24334篇
  1998年   5450篇
  1997年   4517篇
  1996年   3940篇
  1995年   3736篇
  1994年   3335篇
  1993年   2990篇
  1992年   16183篇
  1991年   14947篇
  1990年   14256篇
  1989年   14037篇
  1988年   12641篇
  1987年   12104篇
  1986年   11146篇
  1985年   10353篇
  1984年   6920篇
  1983年   5613篇
  1982年   2723篇
  1979年   5486篇
  1978年   3349篇
  1977年   2970篇
  1975年   2637篇
  1974年   3071篇
  1973年   2869篇
  1972年   2834篇
  1971年   2775篇
  1970年   2511篇
  1969年   2546篇
排序方式: 共有10000条查询结果,搜索用时 281 毫秒
21.
22.
患者女,新生儿,3.4 kg。在当地医院顺产娩出,当即发现患儿肛门闭锁。孕母22岁,系第1胎第1产,产检36W+发现胎儿先天性心脏病。患儿未进食,大小便未排,体格检查:心律齐,心尖瓣膜区可闻及杂音;腹膨隆,未见胃肠型及蠕动波,肝脾肋下未及,听诊肠鸣音弱,移动性浊音阴性。肛检:肛门窝处未见正常肛门结构,搔刮可触及波动感,直肠前庭处可见直径约1 mm瘘口,可见少许胎便排出。主动脉CTA表现为主动脉弓部细,与动脉导管相通,动脉导管及肺动脉主干明显扩张,动脉导管延续降主动脉;心房间隔不连续;升主动脉、肺动脉与心脏连接正常(图1)。诊断为主动脉弓离断(B型);房间隔缺损。  相似文献   
23.
Parotid lymph node (PLN) metastasis greatly worsens the prognosis of patients with oral squamous cell carcinoma (OSCC) and poses a great challenge for further treatment of OSCC. The clinicopathological characteristics and treatment strategies for PLN metastasis from OSCC need to be comprehensively elucidated. A retrospective review of OSCC patients who experienced postoperative PLN metastasis in our department between 2000 and 2018 was performed in this study. A total of 47 OSCC patients with postoperative PLN metastasis were identified. PLN with metastasis were divided into three groups based on the location: parotid tail (PLN-t), superficial lobe (PLN-sl), and deep lobe (PLN-dl). Most of the patients experienced PLN metastasis within less than 12 months after the primary surgery for OSCC. Comparatively, patients with PLN-sl metastasis were more prone to have infiltration of the facial nerve. The tongue and buccal mucosa were the most frequent primary sites associated with PLN metastasis from OSCC. PLNs in the parotid tail were most commonly affected by the metastasized OSCC. Consequently, we recommend a series of strategies for the prevention and treatment of PLN metastasis for OSCC patients. In conclusion, PLNs should not be overlooked during preoperative evaluation and postoperative follow-up examinations for OSCC patients.  相似文献   
24.
Zygomatic implants (ZIs) are used for the oral rehabilitation of patients with maxillectomy defects as an alternative to extensive bone grafting surgeries. New technologies such as computer-assisted navigation systems can improve the accuracy and safety of ZI placement. The intraoral anchorage of fiducial markers necessary for navigation registration is not possible in the case of a severe maxillary defect and lack of residual bone. This technical note presents a novel extraoral registration method for a dynamic navigation system guiding ZI placement in patients with maxillectomy defects. Titanium microscrews were inserted in the mastoid process, supraorbital ridge, and posterior zygomatic arch as registration markers. The mean fiducial registration error (FRE) was 0.53 ± 0.20 and the deviations between the planned and placed ZIs were 1.56 ± 0.54 mm (entry point), 1.87 ± 0.63 mm (exit point), and 2.52 ± 0.84° (angulation). The study results indicate that the placement of fiducial markers at extraoral sites can be used as a registration technique to overcome anatomical limitations in patients after maxillectomy, with a clinically acceptable registration accuracy.  相似文献   
25.
The selection and implementation of a plan for maxillary surgery is of the utmost importance in achieving the desired outcome for the patient undergoing two-jaw orthognathic surgery. Some splint-based and splintless methods, accompanied by computer-assisted techniques, are helpful in improving surgical plan implementation. However, randomized controlled trials focused on this procedure are lacking. This study included 61 patients who underwent bimaxillary surgeries. The patients were randomly assigned to a conventional resin occlusal splint (CROS) group, a digital occlusal splint (DOS) group, or a digital templates (DT) group, in a 1:1:1 ratio. The mean linear distance between the planned and actual postoperative positions of eight selected points on the surfaces of the maxillary teeth was selected as the outcome measure. The distance was significantly smaller in the DT group (1.17 ± 0.66 mm) when compared to both the CROS group (2.55 ± 0.95 mm, P < 0.05) and DOS group (2.15 ± 1.12 mm, P < 0.05). However, the difference between the CROS group and DOS group was not statistically significant. These findings indicate that using digital templates results in the best performance in transferring the surgical plan to the operation environment as compared to the other two types of splints. This suggests that the application of digital templates could provide a reliable treatment option.  相似文献   
26.
Zygomatic implant treatment is widely applied for severe maxillary atrophy to help rehabilitate the maxillary dentition. This retrospective study was performed to evaluate the actual radiographic bone–implant contact (rBIC) lengths of zygomatic implants. The records of 28 patients who underwent zygomatic implant surgery and subsequent follow-up examinations between August 2013 and September 2018 in the Department of Oral and Maxillofacial Surgery, Taipei Tzu Chi Hospital were reviewed. The surgeries were performed by a single surgeon using the same treatment protocol. All patients had a computed tomography scan at 1 year after the surgery. Using three-dimensional imaging software, an investigator measured the rBIC lengths of 66 implants and documented their clinical status. The implant survival rate was 100%. The mean rBIC length was significantly longer in male patients than in female patients (20.80 ± 5.88 mm versus 17.79 ± 6.34 mm; P = 0.028). The mean rBIC length of double zygomatic implants was significantly longer when compared to that of single implants (21.11 ± 6.23 mm versus 17.75 ± 5.85 mm; P = 0.027). This article is novel in reporting the exact rBIC lengths of zygomatic implants in a clinical setting. The results showed that zygomatic implants are a viable treatment modality for full-mouth rehabilitation.  相似文献   
27.
The liberal use of upper endoscopy has led to an increased detection of gastric and duodenal polyps, which are identified in as many as 6 and 4.6% of patient examinations, respectively. Gastroduodenal polyps are a heterogeneous group of lesions that can be neoplastic or non‐neoplastic (e.g. hyperplastic or heterotopical). Most polyps present characteristic topographical features, as well as endoscopic appearance and size. Evaluation of the surrounding mucosa is essential in assessing the underlying pathology (e.g. Helicobacter pylori, autoimmune gastritis or inherited polyposis syndromes). Phylogenetically, gastric and duodenal polyps can be classified according to the epithelial compartment from which they derive. Polyps that arise from the surface epithelium can either be of foveolar or intestinal type, and they can develop from either the native mucosa or the metaplastic epithelium (gastric intestinal metaplasia or duodenal foveolar metaplasia). Other polyps develop from the deeper glandular component, such as pyloric/oxyntic gland derived subtypes. In this review we focus upon epithelial polyps, with an emphasis on the most common and clinically relevant lesions, and present recently described entities.  相似文献   
28.
艾灸作为中医学最古老的疗法之一,作用多样,应用广泛,疗效显著。随着科技的发展,人们对灸法的认识逐渐深入,其中艾烟的相关研究也硕果累累,其安全性广受关注。通过对艾烟作用和安全性评价研究中取得的成果进行归纳分析,以期为艾灸临床安全应用提供指导。  相似文献   
29.
30.
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