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   28766篇
  免费   4091篇
  国内免费   544篇
耳鼻咽喉   314篇
儿科学   466篇
妇产科学   375篇
基础医学   1479篇
口腔科学   9617篇
临床医学   2689篇
内科学   2693篇
皮肤病学   518篇
神经病学   810篇
特种医学   247篇
外国民族医学   1篇
外科学   1363篇
综合类   2393篇
现状与发展   3篇
预防医学   1589篇
眼科学   152篇
药学   5234篇
  40篇
中国医学   1908篇
肿瘤学   1510篇
  2024年   96篇
  2023年   741篇
  2022年   904篇
  2021年   1448篇
  2020年   1685篇
  2019年   1629篇
  2018年   1515篇
  2017年   1408篇
  2016年   1387篇
  2015年   1328篇
  2014年   1925篇
  2013年   2459篇
  2012年   1616篇
  2011年   1660篇
  2010年   1262篇
  2009年   1183篇
  2008年   1106篇
  2007年   1060篇
  2006年   964篇
  2005年   941篇
  2004年   777篇
  2003年   728篇
  2002年   657篇
  2001年   595篇
  2000年   484篇
  1999年   374篇
  1998年   359篇
  1997年   383篇
  1996年   297篇
  1995年   256篇
  1994年   248篇
  1993年   187篇
  1992年   210篇
  1991年   155篇
  1990年   148篇
  1989年   164篇
  1988年   117篇
  1987年   116篇
  1986年   102篇
  1985年   91篇
  1984年   82篇
  1983年   67篇
  1982年   73篇
  1981年   76篇
  1980年   57篇
  1979年   39篇
  1978年   37篇
  1977年   61篇
  1976年   43篇
  1975年   35篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
111.
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   
112.
In a group of 69 patients with pituitary tumours, 12 were found to have evidence of intratumoral haemorrhage on MRI, characterized by high signal intensity on short TR/TE sequences. This was verified in all but 1 patient. The majority of the bleedings occurred in macroadenomas. Five (42%) were prolactinomas and 4 (33%) were non-functioning adenomas. There were 2 GH- and 1 ACTH-secreting tumours. All 5 patients with prolactinomas were on bromocriptine medication. Two of the patients had a clinical picture of pituitary apoplexy. The haemorrhage was not large enough to prompt surgery in any of the patients. However, surgical verification of the diagnosis was obtained in 5 cases, while 6 patients were examined with follow-up MRI.  相似文献   
113.
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   
114.
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   
115.
116.
目的 :探讨两种方法治疗复发性外阴阴道念珠菌病的效果。方法 :将 4 8例复发性外阴念珠菌阴道炎的患者随机分为两组 ,分别给予两种治疗方法。Ⅰ组 (2 5例 ) :每晚米可定泡腾片 1片塞入阴道 ,连续用药 7~ 10d。首次用药后 1周复查 ,临床及白带真菌学培养阴性进入维持期治疗 ,即每周 1次米可定泡腾片 1片阴道塞 ,连续 5个月。Ⅱ组 (2 3例 ) :单次口服氟康唑15 0mg外加每晚米可定泡腾片 1片阴道塞 ,连续用药 7~ 10d。首次用药后 1周复查 ,临床及白带真菌学培养阴性进入维持期治疗 ,即每月月经第 1天口服氟康唑 15 0mg外加每周 1次米可定泡腾片 1片阴道塞、连续 5个月。结果 :首次治疗后 1周及第1个月、12个月两组的治愈率、无效率及假阳性率统计学结果无差异 (P >0 .0 5 ) ,而维持治疗第 1、3和 6个月Ⅱ组的治愈率显著高于Ⅰ组、无效率显著低于Ⅰ组 (P <0 .0 5 )。结论 :氟康唑口服与米可定泡腾片阴道联合用药半年能有效减少治疗期间复发率 ,但停药后并不能降低复发率。  相似文献   
117.
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   
118.
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   
119.
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   
120.
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