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   5978篇
  免费   441篇
  国内免费   87篇
耳鼻咽喉   38篇
儿科学   125篇
妇产科学   213篇
基础医学   771篇
口腔科学   159篇
临床医学   580篇
内科学   1161篇
皮肤病学   95篇
神经病学   381篇
特种医学   280篇
外科学   829篇
综合类   380篇
一般理论   2篇
预防医学   367篇
眼科学   109篇
药学   449篇
  4篇
中国医学   122篇
肿瘤学   441篇
  2023年   49篇
  2022年   109篇
  2021年   201篇
  2020年   112篇
  2019年   143篇
  2018年   214篇
  2017年   131篇
  2016年   138篇
  2015年   216篇
  2014年   253篇
  2013年   313篇
  2012年   474篇
  2011年   471篇
  2010年   287篇
  2009年   259篇
  2008年   339篇
  2007年   362篇
  2006年   336篇
  2005年   277篇
  2004年   247篇
  2003年   241篇
  2002年   208篇
  2001年   129篇
  2000年   147篇
  1999年   101篇
  1998年   46篇
  1997年   36篇
  1996年   26篇
  1995年   36篇
  1994年   29篇
  1993年   24篇
  1992年   64篇
  1991年   46篇
  1990年   34篇
  1989年   38篇
  1988年   37篇
  1987年   29篇
  1986年   30篇
  1985年   36篇
  1984年   31篇
  1983年   25篇
  1982年   25篇
  1981年   29篇
  1980年   13篇
  1979年   18篇
  1978年   14篇
  1977年   16篇
  1976年   14篇
  1975年   11篇
  1974年   10篇
排序方式: 共有6506条查询结果,搜索用时 15 毫秒
1.
沙苑子本草考证   总被引:1,自引:0,他引:1  
张婷婷  柯创  秦路平  吴建军 《中草药》2020,51(16):4348-4354
沙苑子为我国常用中药,药用历史悠久。通过查阅本草文献,对沙苑子名称、基原、功效、产地及伪品5个方面进行考证,得知其名称演变大致经过"白蒺藜""沙苑蒺藜""沙苑子"3个阶段;历代本草记载沙苑子基原为扁茎黄芪的干燥成熟种子,古今应用品种基本一致;沙苑子补肾固精功效的记载自宋《本草衍义》起逐渐清晰明确;沙苑子道地产区自宋时起为陕西沙苑,明清时期产地逐渐转到陕西潼关、山西等地,建国后以陕西省为主向北扩散,以陕西潼关为佳;沙苑子建国前有马薸子、色微绿伪品及紫云英子等混伪品,建国后有紫云英、猪屎豆、华黄芪和直立黄芪的种子等混伪品。为沙苑子正本清源,并为其进一步深入开发提供参考。  相似文献   
2.
Thoracic empyema in uremic patients on maintenance hemodialysis is a challenging situation. The clinical characteristics are rarely reported, and the surgical outcomes remain unclear. We report our experience with video-assisted thoracoscopic surgery in these patients during 10-year period of time. Between 2005 and 2015, we retrospectively reviewed the clinical characteristics, bacteriological studies, and thoracoscopic surgical results of 23 empyema patients undergoing maintenance hemodialysis. The mean patient age was 67.1 ± 12.9 years. All patients had additional preexisting systemic diseases. The mean duration of hemodialysis was 34.7 ± 25.8 months. The infections causing empyema were pneumonia in 11 (47.8%), blood stream infection in 8 (34.8%), and uremic pleuritis in 4 (17.4%). Among the 22 identified microorganisms, the most common pathogen was methicillin-resistant Staphylococcus aureus (31.8%). After thoracoscopic surgery, 8 patients (34.8%) required additional procedures for complications, including 2 patients who required repeated thoracoscopy for hemothorax and 6 (26.1%) patients who required open drainage for residual empyema. The mean hospital stay was 62.4 days, and 6 patients (26.1%) died in the hospital. Univariate and multivariate analyses revealed that maintenance hemodialysis longer than 5 years was a significant factor associated with in-hospital mortality (odds ratio: 14.8, 95% confidence interval 1.5–151.6; p < 0.0001). While surgical management of thoracic empyema in uremic patients undergoing maintenance hemodialysis is associated with high rates of complication and mortality, thoracoscopic surgery is feasible, especially for patients undergoing hemodialysis for less than 5 years.  相似文献   
3.
4.
The modification of semiconductor nanostructures with metallic nanocomponents can promote the separation of electron/hole from photoexited semiconductors by forming heterojunctions, thus exhibit enhanced photocatalytic activities and potential applications. In this study, Pt-based NPs, including Pt, PtCu, and PtCuCo are employed as model co-catalysts to comparatively study their capability to enhance the photocatalytic activity of TiO2 nanosheets. It was found that each of Pt, PtCu, and PtCuCo can greatly enhance the photocatalytic activity of TiO2 toward degradation of organic dyes. Using electron spin resonance spectroscopy, we demonstrated that deposition of Pt-based NPs resulted in more production of reactive oxygen species including hydroxyl radicals, superoxide, and singlet oxygen. The enhancing effects of Pt-based NPs on generation of ROS and photocatalytic activity showed same trend: PtCuCo?>?PtCu?>?Pt. The mechanism underlying the enhancement differences in Pt-based NPs may be mainly related to electronic structure change of Pt in alloying with Cu and Co. These results are valuable for designing hybrid nanomaterials with high photocatalytic efficiency for applications in water purification and antibacterial products.  相似文献   
5.
Kim  SH; Chang  KH; Song  IC; Han  MH; Kim  HC; Kang  HS; Han  MC 《Radiology》1997,204(1):239
  相似文献   
6.
目的 研究异型增生程度不同的口腔白斑和不同分级的鳞癌中谷胱苷肽S转移酶π(GST π)的表达 ,探讨GST π在口腔鳞癌发生发展中的作用。 方法 采用免疫S -P法 ,对 5 4例轻、中、重度异型增生 ,4 7例高、中、低分化的口腔鳞癌 ,7例口腔粘膜上皮单纯增生患者组织进行GST π检测。 结果 口腔粘膜上皮单纯增生组织中未见GST π的表达 ,轻、中、重度异型增生病例中的GST π阳性率分别为4 7.8%、5 2 .9%和 6 4 .2 % ,高于单纯增生组 (P <0 .0 1) ;高分化鳞癌GST π阳性率为 6 4 .7% ,中、低分化鳞癌组分别为 2 8.5 %及 2 2 .2 % ,中、低分化鳞癌组表达均低于高分化鳞癌组及异型增生组 (P <0 .0 5 )。 结论 GST π表达的变化与口腔鳞癌早期的发生发展密切相关  相似文献   
7.
Background : Severe odontogenic infections are serious potentially lethal conditions. Following the death of a patient in the authors' institution this study was initiated to determine the risk factors, management and outcome of a consecutive series of patients.
Methods : All patients admitted to the Royal Adelaide Hospital under the care of the Oral and Maxillofacial Surgery Unit with odontogenic infections in calendar year 2003 were investigated. Detailed information relative to their pre-presentation history, surgical and anaesthetic management and outcome was obtained and analysed.
Results : Forty-eight patients, 32M, 16F, average age 34.5, range 19 to 88 years were treated. All presented with pain and swelling, with 21 (44 per cent) having trismus. Forty-four (92 per cent) were as a result of dental neglect and four (8 per cent) were regular dental patients having endodontic treatment which failed. Of those known to have been treated prior to presentation, most had been on antibiotics. Most patients had aggressive surgical treatment with extraction, surgical drainage, high dose intravenous antibiotics and rehydration. The hospital stay was 3.3 (range 1–16) days. Patients requiring prolonged intubation and high dependency or intensive care (40 per cent) had longer hospitalization. No patient died and all fully recovered.
Conclusion : Severe odontogenic infections are a serious risk to the patient's health and life. Management is primarily surgical with skilled anaesthetic airway management. Antibiotics are required in high intravenous doses as an adjunct and not as a primary treatment.  相似文献   
8.
Purpose  There has been increasing interest in the occupational health of workers in small enterprises, especially in developing countries. This study examines the association between psychosocial job characteristics and fatigue, and attempts to identify risk factors for fatigue among workers of small enterprises in southern Taiwan. Methods  A structured questionnaire was administered to workers receiving regular health examinations between August 2005 and January 2006. The questionnaire collected demographic information and data on working conditions, personal health status and life styles. It also collected information on psychosocial job characteristics, fatigue and psychological distress using three instruments. Results  A total of 647 workers with mean age of 43.7 were completed. Probable fatigue was found in 34.6% of the sample. Fatigue was found by multiple logistic regressions to be associated with the lack of exercise, working in shifts, depression score and lack of social support at workplace. Conclusions  This study found associations between life style, psychosocial job characteristics and fatigue. Because the high prevalence of probable fatigue was found in such small enterprises, the authors suggest that a short interview with some quick questionnaires in health checkup for these small enterprise workers are helpful to early detect psychosocial and fatigue problems.  相似文献   
9.
Hysterosalpingography was performed in 31 patients by means of a low-dose scanning-beam digital radiographic system. The technique permits adequate evaluation of gynecologic abnormalities while allowing significant reduction in radiation: 2.4-mR (6.1 X 10(-7) C/kg) exposure to the skin and 0.7-mrad (7 X 10(-6) Gy) mean dose to the ovaries per image obtained. Sixteen patients demonstrated readily recognizable and documented abnormalities, corroborated by laparoscopy, laparotomy, or other supportive evidence.  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