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   90031篇
  免费   10447篇
  国内免费   4842篇
耳鼻咽喉   991篇
儿科学   1669篇
妇产科学   766篇
基础医学   5260篇
口腔科学   1955篇
临床医学   11764篇
内科学   9407篇
皮肤病学   1294篇
神经病学   2599篇
特种医学   3825篇
外国民族医学   1篇
外科学   8301篇
综合类   21640篇
现状与发展   13篇
一般理论   6篇
预防医学   11857篇
眼科学   1139篇
药学   9549篇
  119篇
中国医学   8483篇
肿瘤学   4682篇
  2024年   489篇
  2023年   1455篇
  2022年   2905篇
  2021年   3707篇
  2020年   3339篇
  2019年   1844篇
  2018年   2333篇
  2017年   2845篇
  2016年   2381篇
  2015年   3927篇
  2014年   4853篇
  2013年   6301篇
  2012年   7810篇
  2011年   8107篇
  2010年   7447篇
  2009年   6792篇
  2008年   6552篇
  2007年   6261篇
  2006年   5544篇
  2005年   4354篇
  2004年   3081篇
  2003年   2536篇
  2002年   2029篇
  2001年   1907篇
  2000年   1304篇
  1999年   690篇
  1998年   436篇
  1997年   447篇
  1996年   436篇
  1995年   362篇
  1994年   287篇
  1993年   279篇
  1992年   227篇
  1991年   192篇
  1990年   166篇
  1989年   185篇
  1988年   172篇
  1987年   140篇
  1986年   141篇
  1985年   144篇
  1984年   115篇
  1983年   103篇
  1982年   76篇
  1981年   78篇
  1980年   51篇
  1979年   45篇
  1978年   35篇
  1977年   40篇
  1976年   39篇
  1971年   29篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
668颗后牙镍铬合金PFM边缘适合性的临床观察   总被引:4,自引:0,他引:4  
目的:观察采用2种边缘形式的后牙烤瓷熔附金属全冠边缘适合性和对牙龈健康的影响.方法:对668颗后牙,分别采用2种边缘形式的后牙烤瓷熔附金属全冠(单冠或桥的基牙)在修复2年后进行复查,检测其边缘适合性及牙龈指数(GI)和牙周探诊深度(PD),用统计学方法分析修复体边缘形式与牙龈病变间的关系.结果:采用羽状边缘360°金属脚边的PFM边缘适合性明显优于凹面肩台型边缘PFM,凹面肩台型边缘的PFM的牙龈病变发生率,明显高于羽状边缘360°金属脚边的PFM,而边缘适合性差者较适合性好者牙龈病变发生率显著增高.结论:后牙PFM的边缘采用羽状边缘360°金属脚边是一种好的选择.  相似文献   
32.
Despite the current popularity of binocular indirect ophthalmoscopy, direct ophthalmoscopes are still commonly used by clinicians for fundus examination. They are considered to be expensive, however, and it has been suggested that this cost can prevent their use by healthcare professionals in developing countries. The Optyse Lens Free Ophthalmoscope is a novel direct ophthalmoscope, without a lens focus system, that allows for comparatively inexpensive manufacture and supply. We compared the clarity of view with the Optyse to that with standard direct ophthalmoscopes, over a sequential cohort of patients with a variety of refractive errors and ocular conditions. The grade of clarity of view with the Optyse Lens Free Ophthalmoscope was less than conventional ophthalmoscopes (Wilcoxon signed rank test, p < 0.0001). This grade of clarity of view was not associated with the ametropia of the ophthalmoscopic observation (Spearman r < or = 0.03, p > or = 0.28) but was with the presence of cataracts (chi2 test, p < 0.0001) with both the Optyse and the conventional ophthalmoscopes. Despite its limitations, the retinal view with Optyse was often within acceptable clinical limits suggesting that this relatively inexpensive ophthalmoscope may have a place when cost prohibits any other type of ophthalmoscope use.  相似文献   
33.
目的 探讨^99mTC-MIBI动态显像对非小细胞肺癌化疗疗效的预测价值。方法 对确诊为不能手术的非小细胞肺癌患者化疗前,静脉注射740mbq ^99mTC-MIBI后分别于30min,2h行SPECT动态扫描,计算早期/晚期肿瘤组织与对侧正常肺组织的放射活性比(T/Ne,T/Nd),全身采用卡铂/顺铂+VP16化疗3周期,随后复查胸部CT,评判化疗疗效及其与^99mTC-MIBI动态显像的关系。结果 78例NSCLC符合入选标准,并完成化疗方案,66例呈阳性显像,12例阴性显像,66例阳性显像中化疗有效率为90.7%,阴性显像12例中化疗全部进展,两者比较差异有显著性(P〈0.01)。结论 ^99mTC-MIBI动态显像的放射活性越高,化疗效果越好,对非小细胞肺癌化疗疗效有预测价值,可为合理制定治疗方案提供重要依据。  相似文献   
34.
AIM: The aim of this study was to investigate the nature and organization of maternal needs and priorities in a neonatal unit. BACKGROUND: The relationship between maternal needs and priorities appears to be an under studied area in neonatal nursing. METHODS: A quantitative survey was carried out based on 209 mothers with premature infants. Two self-assessment schedules were used: critical care maternal needs inventory (J. Leske, Heart and Lung 15, 27-42) and a ranking scale. The data were analysed with multivariate analysis. FINDINGS: Data analysis revealed clear priorities in maternal needs. In particular the need for accurate infant related information was a priority for 93% of the mothers. Good communication practices with professionals were also valued. The mothers displayed altruistic behaviour, and self-related needs took second place. It is proposed that maternal needs demonstrate a hierarchical organization. CONCLUSION: It is important for nurses to consider the individual needs of the mothers, simply because the satisfaction of these needs is essential for maternal well-being.  相似文献   
35.
Methylcholanthrene (approximately 300 micrograms) plus beeswax-impregnated thread, when placed inside the canal of the uterine cervix of virgin female adult mice for 30, 60 and 90 days produced cervical tumors in 0.0, 10 and 30% of mice, respectively. Employing this experimental cervical carcinogenesis model system, the present study evaluated the modulatory influence of medroxyprogesterone acetate (MPA) on the incidences of precancerous and cancerous lesions in the cervical epithelium as well as on phase I and phase II drug metabolizing enzymes and acid soluble sulfhydryl level in the liver. Intramuscular administration of MPA (50 micrograms every 5th day) to the carcinogen-thread inserted mice for 30, 60 and 90 days produced cervical tumors respectively in 0.0, 13.3 and 60.5% (P less than 0.05) of mice. A significant increase (P less than 0.05) in hyperplasia was also observed in the present study. A significant decrease in cytochrome b5 was found after 30 days.  相似文献   
36.
SUMMARY Disease-modifying antirheumatic drugs are used in virtually all patients with established rheumatoid arthritis. An increasingly large number of new drugs is now available. Furthermore, old therapies are being used in novel ways. Treatment is now begun earlier and patients are rarely left untreated. This report summarises recent developments regarding the drugs currently in use and those that may be available in the near future.  相似文献   
37.
A new look at grief   总被引:1,自引:0,他引:1  
  相似文献   
38.
The objective of this study was to investigate the role of the transfollicular pathway in the diffusion process of chemicals through excised human skin in vitro. Skin was obtained from 5 cadavers (3 males, 3 females) within 24 h of death. The age of the subjects varied between 18-77 years. Three radiolabelled drugs, namely 14C-coumarin, 3H-propranolol and 3H-griseofulvin, were studied. The permeation parameters such as flux, lag time, diffusion coefficient and permeability constant were determined across scalp and abdominal skin using the Thomas Diffusion Cell. For all tested substances the flux through scalp skin was higher than across abdominal skin and the lag time was decreased. The differences were statistically significant at p less than 0.05 for coumarin and propranolol. These data suggest that the transfollicular pathway in permeation might have a significant impact on the diffusion parameters for some drugs. Also, in the case of coumarin, permeability seems to be epidermis/dermis-controlled, whereas for griseofulvin and propranolol the Stratum corneum apparently is the permeability limiting barrier.  相似文献   
39.
40.
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