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   137911篇
  免费   9534篇
  国内免费   706篇
耳鼻咽喉   1652篇
儿科学   3588篇
妇产科学   2470篇
基础医学   17597篇
口腔科学   2953篇
临床医学   13544篇
内科学   28464篇
皮肤病学   1824篇
神经病学   12005篇
特种医学   5785篇
外科学   21906篇
综合类   1960篇
现状与发展   1篇
一般理论   173篇
预防医学   12484篇
眼科学   2935篇
药学   9683篇
  4篇
中国医学   179篇
肿瘤学   8944篇
  2023年   676篇
  2022年   1055篇
  2021年   2582篇
  2020年   1480篇
  2019年   2410篇
  2018年   2955篇
  2017年   2134篇
  2016年   2250篇
  2015年   2753篇
  2014年   4062篇
  2013年   6112篇
  2012年   8899篇
  2011年   9473篇
  2010年   5341篇
  2009年   4890篇
  2008年   8432篇
  2007年   9071篇
  2006年   8608篇
  2005年   8764篇
  2004年   8394篇
  2003年   7884篇
  2002年   7705篇
  2001年   1311篇
  2000年   1077篇
  1999年   1424篇
  1998年   1754篇
  1997年   1457篇
  1996年   1382篇
  1995年   1323篇
  1994年   1145篇
  1993年   1101篇
  1992年   866篇
  1991年   898篇
  1990年   789篇
  1989年   785篇
  1988年   799篇
  1987年   779篇
  1986年   807篇
  1985年   879篇
  1984年   932篇
  1983年   882篇
  1982年   1154篇
  1981年   1184篇
  1980年   989篇
  1979年   635篇
  1978年   676篇
  1977年   615篇
  1976年   544篇
  1975年   482篇
  1974年   471篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
Diagnosis and management of anaphylaxis   总被引:7,自引:0,他引:7       下载免费PDF全文
ANAPHYLAXIS IS A SEVERE SYSTEMIC ALLERGIC reaction that is potentially fatal. It requires prompt recognition and immediate management. Anaphylaxis has a rapid onset with multiple organ–system involvement and is mostly caused by specific antigens in sensitized individuals. Reactions typically follow a uniphasic course, however, 20% will be biphasic in nature. The second phase usually occurs after an asymptomatic period of 1–8 hours, but there may be a 24-hour delay. Protracted anaphylaxis may persist beyond 24 hours. Concurrent β-blocker therapy may adversely affect the response to management. Epinephrine is the treatment of choice and should be administered immediately. Secondary measures include circulatory support, H1 and H2 antagonists, corticosteroids and, occasionally, bronchodilators. Post-treatment observation of these patients is necessary, and they should remain within ready access of emergency care for the following 48 hours.  相似文献   
83.
Syphilis can be spread during the practice of dentistry by direct contact with mucosal lesions of primary and secondary syphilis or blood and saliva from infected patients. The dentist also can play an important role in the control of syphilis by identification of the signs and symptoms of syphilis, patient education, and referral. The incidence of syphilis and the impact of control measures are presented with the emphasis on the past 5 years. The signs and symptoms of primary, secondary, latent, and late (tertiary) syphilis are reviewed. Current medical treatment is presented. The oral manifestations of syphilis are discussed as well as the dental management of the infected patient.  相似文献   
84.
We examined the time course effects of continuous PTH on cortical bone and mechanical properties. PTH increased cortical bone turnover and induced intracortical porosity with no deleterious effect on bone strength. Withdrawal of PTH increased maximum torque to failure and stiffness with no change in energy absorbed. INTRODUCTION: The skeletal response of cortical bone to parathyroid hormone (PTH) is complex and species dependent. Intermittent administration of PTH to rats increases periosteal and endocortical bone formation but has no known effects on intracortical bone turnover. The effects of continuous PTH on cortical bone are not clearly established. MATERIALS AND METHODS: Eighty-four 6-month-old female Sprague-Dawley rats were divided into three control, six PTH, and two PTH withdrawal (WD) groups. They were subcutaneously implanted with osmotic pumps loaded with vehicle or 40 microg/kg BW/day human PTH(1-34) for 1, 3, 5, 7, 14, and 28 days. After 7 days, PTH was withdrawn from two groups of animals for 7 (7d-PTH/7d-WD) and 21 days (7d-PTH/21d-WD). Histomorphometry was performed on periosteal and endocortical surfaces of the tibial diaphysis in all groups. microCT of tibias and mechanical testing by torsion of femora were performed on 28d-PTH and 7d-PTH/21d-WD animals. RESULTS AND CONCLUSIONS: Continuous PTH increased periosteal and endocortical bone formation, endocortical osteoclast perimeter, and cortical porosity in a time-dependent manner, but did not change the mechanical properties of the femur, possibly because of addition of new bone onto periosteal and endocortical surfaces. Additionally, withdrawal of PTH restored normal cortical porosity and increased maximum torque to failure and stiffness. We conclude that continuous administration of PTH increased cortical porosity in rats without having a detrimental effect on bone mechanical properties.  相似文献   
85.
86.
Unravelling the cause of a neutropenia poses a complex diagnostic challenge. The differential diagnosis ranges from life threatening disease to transient benign causes of little clinical significance. This review offers a practical guide to investigating the neutropenic child, and highlights features that merit specialist referral. Therapeutic options, the role of long term follow up, and the complications of severe chronic neutropenia are considered.  相似文献   
87.
AMPA receptor potentiators enhance AMPA receptor-mediated glutamatergic neurotransmission and may have therapeutic potential as cognitive enhancers or antidepressants. The anatomical basis for the action of AMPA receptor potentiators is unknown. The aim of this study was to determine the effects of the biarylpropylsulfonamide AMPA receptor potentiator, LY404187 (0.05 to 5 mg/kg subcutaneously), upon cerebral glucose utilization and c-fos expression using 14C-2-deoxglucose autoradiography and c-fos immunocytochemistry. LY404187 (0.5 mg/kg) produced significant elevations in glucose utilization in 28 of the 52 anatomical regions analyzed, which included rostral neocortical areas and the hippocampus, as well the dorsal raphe nucleus, lateral habenula, and locus coeruleus. No significant decreases in glucose utilization were observed in any region after LY404187 administration. The increases in glucose utilization with LY404187 (0.5 mg/kg) were blocked by pretreatment with the AMPA receptor antagonist LY293558 (25 mg/kg), indicating that LY404187 acts through AMPA receptor-mediated mechanisms. LY404187 (0.5 mg/kg) also produced increases in c-fos immunoreactivity in the cortex, locus coeruleus, and the dorsal raphe nucleus. These studies demonstrate neuronal activation in key brain areas that are associated with memory processes and thus provide an anatomical basis for the cognitive enhancing effects of AMPA receptor potentiators.  相似文献   
88.
The hairline and frontal hair volume are frequently overlooked aspects of attractive facial proportion and overall facial aesthetics. The author contends that patient benefit from hair restoration surgery is significant, and these procedures should be routinely considered as part of a complete facial rejuvenation.  相似文献   
89.
90.
Health education campaigns which utilise the mass media generally employ advertising techniques. Television and print media are considered more influential, with radio being primarily used for awareness raising and campaign support messages. There is relatively little research into the effectiveness of radio talkback programs in promoting health or reducing illness. This paper argues a case for health and welfare professionals to utilise talkback radio as part of their health promotion activities.  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