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   23319篇
  免费   3059篇
  国内免费   460篇
耳鼻咽喉   296篇
儿科学   336篇
妇产科学   351篇
基础医学   1292篇
口腔科学   9527篇
临床医学   1400篇
内科学   1858篇
皮肤病学   475篇
神经病学   313篇
特种医学   216篇
外国民族医学   1篇
外科学   1116篇
综合类   1947篇
现状与发展   3篇
预防医学   1100篇
眼科学   60篇
药学   3462篇
  28篇
中国医学   1623篇
肿瘤学   1434篇
  2024年   46篇
  2023年   507篇
  2022年   562篇
  2021年   993篇
  2020年   1198篇
  2019年   1209篇
  2018年   1123篇
  2017年   1063篇
  2016年   1066篇
  2015年   1019篇
  2014年   1430篇
  2013年   1924篇
  2012年   1280篇
  2011年   1333篇
  2010年   1015篇
  2009年   940篇
  2008年   922篇
  2007年   901篇
  2006年   808篇
  2005年   824篇
  2004年   703篇
  2003年   664篇
  2002年   601篇
  2001年   545篇
  2000年   447篇
  1999年   365篇
  1998年   335篇
  1997年   372篇
  1996年   283篇
  1995年   255篇
  1994年   237篇
  1993年   179篇
  1992年   200篇
  1991年   151篇
  1990年   144篇
  1989年   160篇
  1988年   116篇
  1987年   111篇
  1986年   98篇
  1985年   85篇
  1984年   80篇
  1983年   65篇
  1982年   74篇
  1981年   73篇
  1980年   55篇
  1979年   39篇
  1978年   36篇
  1977年   60篇
  1976年   42篇
  1975年   34篇
排序方式: 共有10000条查询结果,搜索用时 296 毫秒
91.
rhGM-CSF对小鼠口腔粘膜损伤的防治作用   总被引:1,自引:0,他引:1  
目的:探讨rhGM-CSF促进口腔腔溃愈合的作用机制。方法:取体外培养的胎儿口腔粘膜成纤维细胞,用rhGM-CSF刺激成纤维细胞后第2、4、6天用细胞计数及^3H-胸腺嘧啶掺入法(^3H-TdR)测定其增殖情况,结果rhGM-CSF对胎儿口腔粘膜成纤维细胞增殖及DNA合成有刺激作用,在80-100ng/ml时,细胞生长达到最佳状态,过高浓度rhGM-CSF的刺激作用反而下降。结论:rhGM-CSF可以通过刺激成纤维细胞增殖及DNA合成促进口腔溃疡愈合。  相似文献   
92.
A morphometric study of nucleolar organizer regions (NOR) was performed to analyze their distribution, volume, number and shape in the different strata of human normal oral mucosa epithelium and papilloma and in squamous cell carcinoma employing microphotographs of silver-stained paraffin sections. The different NOR-related parameters evidenced significant differences between normal mucosa, papilloma and squamous cell carcinoma. The functional polarity of normal mucosa epithelium and of papilloma is also evidenced in terms of NOR-related parameters. The discriminative value of certain NOR parameters was demonstrated.  相似文献   
93.
Background: It has been suggested that oral cobalamin (vitamin B12) therapy may be an effective therapy for treating cobalamin deficiencies related to food‐cobalamin malabsorption. However, the duration of this treatment was not determined. Patients and method: In an open‐label, nonplacebo study, we studied 30 patients with established cobalamin deficiency related to food‐cobalamin malabsorption, who received between 250 and 1000 μg of oral crystalline cyanocobalamin per day for at least 1 month. Endpoints: Blood counts, serum cobalamin and homocysteine levels were determined at baseline and during the first month of treatment. Results: During the first month of treatment, 87% of the patients normalized their serum cobalamin levels; 100% increased their serum cobalamin levels (mean increase, +167 pg/dl; P < 0.001 compared with baseline); 100% had evidence of medullary regeneration; 100% corrected their initial macrocytosis; and 54% corrected their anemia. All patients had increased hemoglobin levels (mean increase, +0.6 g/dl) and reticulocyte counts (mean increase, +35 × 106/l) and decreased erythrocyte cell volume (mean decrease, 3 fl; all P < 0.05). Conclusion: Our findings suggest that crystalline cyanocobalamin, 250–1000 μg /day, given orally for 1 month, may be an effective treatment for cobalamin deficiencies not related to pernicious anemia.  相似文献   
94.
The objective of the present study was to assess possible adaptive functional changes in the masticatory system after insertion of fixed prostheses supported by osseointegrated implants in the edentulous mandible. Registrations of mandibular movement characteristics and maximal biteforce were performed at insertion and after 1 week, 3 months and 1 year after connection. The duration of the opening and closing phase decreased and maximal biteforce increased significantly (p < or = 0.05-0.001) from connection of the prostheses to the annual check-up. However, the process of functional adaptation implied 2 identified stages. An immediate phase that occurred within the 1st week, probably due to altered impact from mechano-sensitive receptors and a later more time-dependent phase, based on learning and new cortical engrams. Accordingly, the process of adaptation will continue over a long period of time.  相似文献   
95.
96.
目的:观察第二、三代口服避孕药(COC)对育龄妇女体重指数、血压、血糖和血脂的影响。方法:将自愿服用COC避孕1年的妇女105例随机分为两组,其中54例给予第二代COC(EE/LNG组),51例给予第三代COC(EE/DG组)。并对研究前后所有病例的体重指数(BMI)、血压、血糖和血脂代谢指标进行比较分析。结果:EE/LNG组:BMI、收缩压、舒张压、甘油三酯(TG)、总胆固醇(TC)、低密度脂蛋白(LDL)和载脂蛋白B(ApoB)水平均升高,高密度脂蛋白(HDL)水平下降,血糖、载脂蛋白AI(ApoAI)水平无明显改变。EE/DG组收缩压、TG、HDL水平升高,BMI、舒张压、血糖、TC、LDL、ApoAI和ApoB均未发生显著变化。以上所有测量指标均未超出正常范围。结论:使用1年第二、三代COC对妇女BMI、血压和血脂代谢都有微弱的影响,对空腹血糖无明显影响。第三代COC对妇女BMI、收缩压、舒张压、TG、TC、LDL、HDL水平和ApoB的不利影响小于第二代,更加安全可靠。  相似文献   
97.
Histoplasmosis is a fungal disease that affects humans and is caused by Histoplasma capsulatum. The presentation of the infection may be acute, chronic, or disseminated. The disseminated form has extrapulmonary manifestations which may include oral manifestation a. A patient with AIDS sought treatment and he had disseminated histoplasmosis with oral manifestations. The purpose of this case report and literature review is to emphasize the role the dental team has in the diagnosis of disseminated disease when a patient presents with oral manifestations associated with the disease. This case report is clinically relevant because it is not uncommon for oral manifestations to be one of the first signs of systemic disease.  相似文献   
98.
利多卡因用于放射性黏膜损伤所致口腔疼痛的疗效观察   总被引:3,自引:0,他引:3  
目的观察利多卡因稀释液用于放射性黏膜损伤后口腔疼痛的疗效。方法首次诊断和初次治疗的头颈部放疗患者共90例,放射总剂量60—72Cy/30—35次,随机分为对照组44例和观察组46例;对照组患者放疗期间给予饮食指导和静脉营养支持,观察组患者除饮食指导和静脉营养支持以外,在口腔疼痛时和餐前给予利多卡因含漱液20ml含漱;当放射剂量达20、40、60Gy时比较两组患者的口腔疼痛分度状况和体重下降状况;所有资料采用秩和检验。结果观察组在放射剂量20、40、60Gy时,口腔疼痛和体重下降均明显少于对照组。结论利多卡因稀释液含漱能明显缓解放射性黏膜损伤所致的口腔疼痛,进而改善患者的进食和营养状况。  相似文献   
99.
Investigators have tried to identify a level of seric specific immunoglobulin E (IgE) that had a sufficient predictive value to diagnose a food allergy without having will resort to the food challenge. To search in literature, all the studies that have estimated the possibility to identify a level of seric specific cow milk IgE with a positive predictive value (PPV) of 95% for the first diagnosis of cow's milk allergy (CMA) in pediatric age. We have identified six studies, nearly all studies suffer from relevant methodological bias. Proposed cut-off are all different. The studied pediatric populations were highly selected. Also neglecting the methodological bias of the studies and the great difference of value between the proposed cut-off, it always remains to consider that the pre-test probability of having a CMA between the children enrolled in the six studies included in this review is particularly high. The likelihood ratio helps to transfer the results of a study on a diagnostic test just to our population, and it is more realistic rather than to entrust itself to the PPV or the negative predictive value, that are much influenced from the prevalence of the disease in the studied population.  相似文献   
100.
The mortality of cerebrovascular diseases in Denmark was analysed for men and women 15-44 years of age, in a 14-year period before and after the appearance of oral contraceptives (OC) in 1966. 1,670 deaths were registered over 28 years, during which the female incidence of cerebrovascular deaths increased by 19% (P less than 0.025), while the male mortality was unchanged. Women showed a percentage increase in deaths from cerebral thromboembolic attacks (CTA) of 33%, men a fall of 14%. The increase of female CTA deaths was most pronounced in the young fertile group, the age group with a high OC use. A relative risk of CTA of 3.3-4.5 for OC users compared with non-users could explain the CTA trend difference between women and men. No other single risk factor responsible for the observed trends could be identified. Both women and men had a significant increase in the mortality of subarachnoidal hemorrhages, and a significant fall in the mortality of intracerebral hemorrhages.  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