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   29238篇
  免费   2281篇
  国内免费   76篇
耳鼻咽喉   272篇
儿科学   1084篇
妇产科学   897篇
基础医学   3819篇
口腔科学   600篇
临床医学   3984篇
内科学   5492篇
皮肤病学   600篇
神经病学   2877篇
特种医学   718篇
外国民族医学   2篇
外科学   2450篇
综合类   298篇
一般理论   29篇
预防医学   3952篇
眼科学   532篇
药学   1895篇
  1篇
中国医学   38篇
肿瘤学   2055篇
  2023年   322篇
  2022年   522篇
  2021年   992篇
  2020年   641篇
  2019年   973篇
  2018年   1020篇
  2017年   812篇
  2016年   730篇
  2015年   828篇
  2014年   1091篇
  2013年   1599篇
  2012年   2214篇
  2011年   2241篇
  2010年   1214篇
  2009年   1047篇
  2008年   1761篇
  2007年   1883篇
  2006年   1694篇
  2005年   1544篇
  2004年   1428篇
  2003年   1363篇
  2002年   1178篇
  2001年   322篇
  2000年   234篇
  1999年   289篇
  1998年   231篇
  1997年   166篇
  1996年   168篇
  1995年   149篇
  1994年   147篇
  1993年   108篇
  1992年   148篇
  1991年   149篇
  1990年   131篇
  1989年   152篇
  1988年   137篇
  1987年   148篇
  1986年   123篇
  1985年   135篇
  1984年   95篇
  1983年   98篇
  1982年   110篇
  1981年   71篇
  1980年   73篇
  1979年   83篇
  1978年   90篇
  1977年   72篇
  1976年   76篇
  1975年   62篇
  1973年   63篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
This paper presents the results of a qualitative study conducted by midwife researchers into women's experience of new motherhood. Data were collected using focus groups involving 55 first-time mothers and analysed using grounded theory method. The analysis produced six categories: 'realizing', 'unready', 'drained', 'aloneness', 'loss' and 'working it out'. The core category, 'becoming a mother', integrates all other categories and encapsulates the process of change experienced by women. Also explained are factors mediating the often distressing experience of becoming a mother. The analysis provides a conceptualization of early motherhood enabling the development of strategies for midwives, nurses and others helping women negotiate this challenge.  相似文献   
64.
Four meanings of medical necessity have emerged, evolved, and dominated past and current health policy debates about the appropriate level of service coverage under Canada's health insurance program. To explore the shift in definition, provincial government and national health care association position papers responding to federal legislative and policy reviews of Canada's health insurance program from 1957 to 1984 were examined, as were more current reports on medical necessity. Four meanings of medical necessity predominated: "what doctors and hospitals do"; "the maximum we can afford"; "what is scientifically justified"; and "what is consistently funded across all provinces." These meanings changed with time as different stakeholder associations and governments redefined the concept of medical necessity to achieve different policy objectives for health service coverage under Canada's health insurance program.  相似文献   
65.
Poor nutritional status and inadequate dietary intake in intravenous drug misusers (IVDMs) is a well-recognized problem among those involved in their care. However, there are very few published studies to substantiate these observations. This paper provides a review of the current literature and outlines the aims of dietary advice for IVDMs.  相似文献   
66.
Promotion of mouthguards among amateur football players in Victoria   总被引:2,自引:0,他引:2  
Abstract: Wearing mouthguards while playing contact sports reduces the prevalence and severity of orofacial injuries. We report on a 1991–92 promotion of mouthguard use among amateur football players in Melbourne. Four questionnaires were completed by players (1991 season: middle: n =638, 49 per cent response; late: n =770, 51 per cent; 1992: early: n =505, 26 per cent; late: n =698, 54 per cent), in four age groups (16–19, 20–23, 24–29, 30–44 years), about perceived mouthguard value and usage, injury experience, and awareness of a promotional message. Over the two seasons, mouthguard ownership and consistent wear increased and dental injuries decreased. Ownership of mouthguards increased among: 20–23 year olds and 30–44 year olds (13 and 16 per cent); managers, tradespersons, salespersons, labourers and the unemployed (14–19 per cent); residents of northern and western regions (12 and 13 per cent); those with 6 to 10 years of education (29 per cent); players in old boys' networks (13 per cent); and those with English as a first language (8 per cent). Consistent wear was high at matches (89 per cent) but low at training (13 per cent), owing to perceived lack of physical contact. Of dental injuries reported by 25–31 per cent, fractures predominated over luxations and avulsions. Fractures and avulsions were more common at matches than training; luxations predominated at training. When a mouthguard was not worn, the likelihood of a fractured or avulsed tooth was at least twice that when a mouthguard was worn. Some injuries occurred despite the wearing of mouthguards. The promotional message appeared effective in increasing mouthguard use; newspapers and football journals provided effective message locations for players, and ground signs and the electronic scoreboard for spectators.  相似文献   
67.
The effects of immobilization and remobilization on the biomechanical and morphological properties of the femur-medial collateral ligament-tibia complex and each of its components were investigated in the rabbit. Specimens that had been obtained after periods of unilateral immobilization of the knee and remobilization were evaluated for structural properties. In addition, the mechanical properties of the substance of the medial collateral ligament and the histological characteristics of both the substance of the ligament and its sites of insertion were evaluated. After immobilization, there were significant reductions in the ultimate load and energy-absorbing capabilities of the bone-ligament complex, and an increased number of failures occurred by tibial avulsion. The tissue of the medial collateral ligament also became less stiff as a result of immobilization. Histologically, the femoral and tibial insertion sites showed increased osteoclastic activity, resorption of bone, and disruption of the normal attachment of the bone to the ligament. With remobilization, the ultimate load and energy-absorbing capabilities of the bone-ligament complex improved but did not return to normal. Failure by tibial avulsion became less frequent, and the stress-strain characteristics of the medial collateral ligament returned to normal. Histologically, the sites of insertion of the ligament also showed evidence of recovery.  相似文献   
68.
This article reviews the mechanisms of pulmonary injury associated with hydrocarbon poisoning. The evolution of clinical and radiographic changes is discussed, along with appropriate treatment. Preventing aspiration in the emergency department is the most effective therapy for these children in the first few hours after ingestion.  相似文献   
69.
MR imaging of pineal cysts   总被引:2,自引:0,他引:2  
Identification of pineal cysts with imaging modalities other than magnetic resonance (MR) has been infrequent, despite a reported autopsy incidence of as high a 40%. We recently identified 15 patients in whom pineal cysts were seen on MR. These cysts ranged from 5 to 15 mm in maximum diameter. The cyst walls were thin, usually measuring less than 2 mm. The signal characteristics of the fluid within the cysts paralleled that of CSF, although it differed somewhat in signal intensity from CSF collections in which there was pulsatile motion. All lesions were midline in location. There was no significant mass effect, although mild flattening of the superior colliculi could be seen. Two cases were operated on; at operation, typical pineal cysts were found, with one containing hemosiderin-laden proteinaceous material, which accounted for its markedly higher signal intensity. It is important that this entity be recognized so that these lesions are not confused with pineal tumors.  相似文献   
70.
Chylous ascites is an uncommon clinical entity associated with lymphatic obstruction usually caused by underlying malignancy. The authors describe a patient with chylous ascites caused by constrictive pericarditis in the absence of mechanical lymphatic obstruction. Pathophysiological mechanisms for the development of chylous ascites in constrictive pericarditis include augmented lymph production and high impedance to lymph drainage caused by central venous hypertension. After pericardiectomy, the patient's ascites and edema resolved. Constrictive pericarditis should be considered a rare but potentially curable cause of chylous ascites.  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