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   9758篇
  免费   959篇
  国内免费   30篇
耳鼻咽喉   116篇
儿科学   355篇
妇产科学   206篇
基础医学   1444篇
口腔科学   161篇
临床医学   1222篇
内科学   1844篇
皮肤病学   132篇
神经病学   832篇
特种医学   511篇
外国民族医学   1篇
外科学   1229篇
综合类   245篇
一般理论   3篇
预防医学   984篇
眼科学   172篇
药学   696篇
中国医学   5篇
肿瘤学   589篇
  2021年   121篇
  2020年   89篇
  2019年   117篇
  2018年   159篇
  2017年   100篇
  2016年   106篇
  2015年   160篇
  2014年   209篇
  2013年   271篇
  2012年   451篇
  2011年   421篇
  2010年   250篇
  2009年   245篇
  2008年   406篇
  2007年   425篇
  2006年   430篇
  2005年   434篇
  2004年   402篇
  2003年   365篇
  2002年   373篇
  2001年   349篇
  2000年   341篇
  1999年   273篇
  1998年   159篇
  1997年   154篇
  1996年   139篇
  1995年   137篇
  1994年   131篇
  1993年   115篇
  1992年   257篇
  1991年   197篇
  1990年   222篇
  1989年   232篇
  1988年   197篇
  1987年   194篇
  1986年   167篇
  1985年   160篇
  1984年   140篇
  1983年   136篇
  1982年   88篇
  1981年   108篇
  1980年   81篇
  1979年   121篇
  1978年   114篇
  1977年   76篇
  1976年   78篇
  1975年   85篇
  1974年   85篇
  1971年   72篇
  1970年   70篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
This intervention study compares the effectiveness of two approaches on caregiving stress reduction. Caregivers' psychobiological symptom experience and coping were profiled over time by identifying the types of stress-related symptoms most frequently experienced. Following pretesting (and selected matching procedures) using family functioning, coping, stress and mental status instruments, random assignment of caregivers was made to one of four groups: educative/didactic, psychotherapeutic/support, placebo, or control. Patients were tested at the end of eight weekly 2-hour sessions and again at 1-, 3-, 6-, and 12-month intervals after treatment. Although both the educative and psychotherapeutic groups were effective interventions for the reduction of strain, the psychotherapeutic/support group was the most effective over time, both at posttest and at the 3-month intervals. Neither group intervention was more effective than the control groups in reducing other types of stress, including anxiety, somatization, or depression. The psychobiological symptoms experienced by caregivers peaked at crisis periods in the caregiving trajectory, or when multiple demands were made of the caregiver during any one point in time.  相似文献   
42.
The history and findings in a patient with erythroleukaemia who developed a fungal brain abscess during the agranulocytic phase of induction treatment is reported. The radiological features of fungal infection are reported, with emphasis on the importance of clinical judgement in making the diagnosis. The autopsy findings further illustrate the increasing importance of this previously very rare condition.  相似文献   
43.
A technique is presented whereby a median mandibulotomy of an atrophic edentulous mandible is performed to gain access to an oropharyngeal tumor and is subsequently reapproximated with a four-pin FMI. The procedure allows reduction of the osteotomy site and provides intraoral implants that increase the stability and retentive properties of a mandibular prosthesis.  相似文献   
44.
 We present a rare case of a 27-year-old man sustaining a bilateral fracture dislocation of the sacroiliac joints without disruption of the anterior pelvis, following a fall from a height. Reconstructed images in the coronal plane and three-dimensional CT images were invaluable in the diagnosis and assessment of this injury.  相似文献   
45.
OBJECTIVES: The purpose of this study was to determine the acceptability, effectiveness, and cost of a face-to-face educational outreach intervention in the context of a program aimed at increasing cervical screening in Victoria, Australia. METHODS: All identified general practitioners in a specified intervention area were offered a visit by a general practitioner educator. Practitioners completed a questionnaire evaluating the acceptability of the visit. Odds ratios for a woman being screened in the 3 months following the visits were determined. RESULTS: Fifty-nine general practitioners (69.4%) accepted the offer of a visit. Most found both the process and the content of the intervention to be acceptable. The intervention and nonintervention regions did not differ either before or after the intervention. In both regions, there was a statistically significant increase in number of Pap tests performed. There was no difference in the change in screening between the two regions. Costs were estimated at Au$34 per general practitioner visited. CONCLUSIONS: This strategy cannot be recommended for widespread use in a cervical screening program.  相似文献   
46.
In patients with allergic asthma and rhinitis high numbers of hypodense eosinophils (HE) have been demonstrated. In a previous study we reported that asthmatic and healthy children had more HE than their adult counterparts. We assumed that this might, in part, he due to the presence of immature eosinophils in children. To distinguish between immature and activated eosinophils, determination of eosinophil cationic protein (ECP) might be interesting as it is known that high serum levels of ECP are associated with increased activation of eosinophiis. In this study we determined (he levels of ECP in scrum in asthmatic and healthy children and adults trying to distinguish activated from immature eosinophils. We found that ECP levels were not increased in children (healthy and asthmatic) compared to adults (healthy and asthmatic). This supports the hypothesis that increased numbers of HE in childhood are, at least in part, immature eosinophils. Nevertheless, we could confirm that inflammation was present in children because soluble interleukin-2-receptor (slL-2R), a marker of lymphocyte activation, was higher in asthmatic children as compared to healthy children. IL-6, a marker of macrophage/monocyte activation, was not different in the different patient groups. We conclude that although signs of inflammation are present in childhood asthma, the increased numbers of HE in children are in part due to the presence of immature eosinophils.  相似文献   
47.
The purpose of this study is to develop a new vascularized epiphyseal plate model in the New Zealand White rabbit using a metatarsal epiphyseal plate having limited longitudinal growth potential. Such a model could be utilized in various experiments aimed at manipulating epiphyseal plate growth. The viability of the harvested live subject grafts was demonstrated with continued epiphyseal uptake during Tc99-MDP radionuclide bone scanning. The currently described models used in epiphyseal transplant research all involve long bone epiphyseal plates with significantly greater growth potential than the new metatarsal model. This new model therefore fills a void in the field by allowing investigators to transplant a growth plate with limited growth potential into any heterotopic site and study the effects of various hormonal and physical influences upon epiphyseal plate growth performance. © 1995 Wiley-Liss, Inc.  相似文献   
48.
The diabetic neuropathic ulcer is typically slow to heal and recurrent. Macrovascular insufficiency is usually excluded as foot pulses are present and ankle:brachial pressure ratios are not decreased. These assessments cannot however exclude more distal vascular disease. Digital pressure measurements enable a reliable assessment of the distal peripheral vascular status to be made. The aim of this study was therefore to use toe pressures to assess the contribution of distal ischaemia in the pathogenesis of the neuropathic ulcer. Sixteen diabetic patients with recurrent neuropathic foot ulceration had their toe pressures compared to 10 neuropathic patients without a history of foot ulceration, 10 diabetic control subjects, and 11 normal subjects. Four non-diabetic patients with neuropathy and foot ulceration were also assessed. All subjects had ankle:brachial pressure indices ≧ 1. Toe pressure was assessed using laser Doppler flowmetry to record the return of skin blood flow. The toe:brachial pressure index (TBI) was then calculated. The diabetic patients with a history of recurrent neuropathic ulceration, had the lowest mean TBI, 0.63 ± 0.14 (SD), compared to the non-ulcerated diabetic neuropathy patients, the diabetic control subjects, and the normal subjects. 0.84 ± 0.11, 0.82 ± 0.1, and 0.81 ± 0.07, p < 0.01, respectively. Three of the four non-diabetic patients with neuropathic foot ulceration also had an abnormally low TBI. Reduced toe pressure measurements are thus found to be associated with neuropathic foot ulceration. The contribution of distal ischaemia in the pathogenesis of the diabetic neuropathic foot ulcer needs to be evaluated. One hundred and eight non-insulin-dependent diabetic patients who had been tested for autonomic dysfunction in 1984/85 were re-evaluated 5 years later. Autonomic function was assessed by means of four cardiovascular tests (heart rate variation during deep breathing and standing, and blood pressure variation after standing and sustained handgrip). Eighteen subjects were lost to follow-up; in the 90 patients who completed the study, both the deep breathing and the handgrip test significantly worsened (respectively from 13.7 ± 7.8 to 11.6 ± 6.3 beats min?1 p < 0.01, and from 16.9 ± 8.2 to 12.7 ± 7.1 mmHg, p < 0.001), whereas both the 30:15 ratio and the variation of blood pressure on standing did not change. The impairment of a comprehensive evaluation score (from 2.5 ± 1.7 to 3.0 ± 1.5; p < 0.05) also confirmed the gradual deterioration of autonomic function over the study period.  相似文献   
49.
Feasibility analysis is an important aspect of business planning. A feasibility study is a study of the impacts of revenues, cost, and returns on a decision. It helps answer the questions of "What share of total sales can be attained?" "What revenues will be generated?" "What costs will be incurred?" "What will be the return on investment?" The discipline of going through a systematic approach to analyze market demand, cost requirements, and return on investment will improve business decisions by eliminating risk and increasing the possibility of successful ventures.  相似文献   
50.
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