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   22966篇
  免费   1437篇
  国内免费   41篇
耳鼻咽喉   152篇
儿科学   719篇
妇产科学   797篇
基础医学   2924篇
口腔科学   309篇
临床医学   3682篇
内科学   3790篇
皮肤病学   211篇
神经病学   2372篇
特种医学   404篇
外科学   2045篇
综合类   259篇
一般理论   32篇
预防医学   3382篇
眼科学   325篇
药学   1299篇
中国医学   23篇
肿瘤学   1719篇
  2024年   15篇
  2023年   159篇
  2022年   230篇
  2021年   430篇
  2020年   299篇
  2019年   451篇
  2018年   550篇
  2017年   416篇
  2016年   471篇
  2015年   559篇
  2014年   787篇
  2013年   1146篇
  2012年   1698篇
  2011年   1832篇
  2010年   970篇
  2009年   861篇
  2008年   1576篇
  2007年   1712篇
  2006年   1597篇
  2005年   1581篇
  2004年   1573篇
  2003年   1445篇
  2002年   1413篇
  2001年   238篇
  2000年   157篇
  1999年   191篇
  1998年   270篇
  1997年   235篇
  1996年   163篇
  1995年   192篇
  1994年   164篇
  1993年   125篇
  1992年   118篇
  1991年   91篇
  1990年   70篇
  1989年   65篇
  1988年   57篇
  1987年   58篇
  1986年   36篇
  1985年   61篇
  1984年   54篇
  1983年   48篇
  1982年   60篇
  1981年   54篇
  1980年   32篇
  1979年   20篇
  1978年   16篇
  1977年   14篇
  1974年   10篇
  1969年   8篇
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
71.
72.
We present three patients with Treacher Collins or Pierre Robin syndromes who had historical and physical evidence of airway obstruction, difficulty feeding, and sleep disturbances. These preoperative findings correlated with difficult airway management intraoperatively. Based on this experience, we recommend that children with obstructive symptoms have laryngoscopy prior to anaesthetic induction. If the glottic opening is visualized, inhalational induction can proceed. If the glottic structures cannot be visualized, then the anaesthetist must choose between awake oral or nasal intubation, elective tracheostomy, or fiberoptic intubation. In all cases, a tracheostomy tray should be ready and a surgeon experienced in paediatric tracheostomy should be in attendance. After intubation, anaesthesia is best maintained with oxygen and a potent inhalational agent. Extubation should only be done with the patient fully awake and with emergency airway equipment immediately available. Postoperatively, these patients should be transferred to an intermediate care area or intensive care unit where they can be observed closely since delayed complications of airway obstruction are common in this group of patients.  相似文献   
73.
74.
On a daily basis, clinicians make decisions regarding therapies to result in the best outcome for their patients. These decisions should be based on the evidence in the literature, indicating a therapy will cause the best outcome. To facilitate this, many professional societies and scientific journals have published technical and scientific reviews, as well as evidence-based standards of care focused on many issues of nutrition support practice. This paper provides an overview of how these reviews and standards of care are derived to promote both the understanding of what they can and cannot do to enhance clinical practice.  相似文献   
75.
Triphalangeal thumb (TPT) is a rare congenital disorder characterised by a long, finger-like thumb with three phalanges instead of two. It can occur as an isolated defect, in association with other abnormalities of the hands and feet, or as a part of a syndrome. Sporadic cases have been described, but it is usually inherited as an autosomal dominant trait. In order to examine skeletal morphology in different phenotypic variations of this disorder, we performed metacarpophalangeal pattern profile analysis in one kindred with this disorder. A characteristic profile occurred in all affected people, based on the individual lengthening or shortening of the thumb bones. Comparison of the affected and unaffected people from this family with people with a different genetic background suggests that the described profile is specific for TPT and could be used as a helpful diagnostic tool in syndromes which include TPT.  相似文献   
76.
Preliminary evaluation of the processes of changing to a low-fat diet   总被引:3,自引:2,他引:1  
The purpose of the present paper is to identify the processesof changing dietary fat consumption using Prochaska's transtheoreticalmodel. This model assigns individuals into a series of stages,emphasizing the cognitive, social and behavioral steps of change.At each of the stages an individual focuses on different processes,or coping strategies, to enable movement to the next stage.Dietary process items were created by a multidisciplinary teamusing the smoking processes as a model. These items were subjectedto a Q-sort and piloted in convenience samples. The processitems were distributed with staging questionnaires to 720 membersof an outdoor folk music festival audience. The final groupof 121 process items was subjected to exploratory factor analysisof principle components with varimax rotation. Eight independentfactors emerged during this factor analysis. The processes measuredby the final 60-item questionnaire relate to the stages of changein the hypothesized manner. Applications of this model to interventionsettings seem possible.  相似文献   
77.
This paper describes the implementation of a community-based youth violence prevention project that utilized an educational curriculum and a mass media campaign. The extent of penetration of the intervention into target areas and the degree of contamination of control areas are assessed, and the most frequently contacted forms of educational outreach are identified. Two sources of data, provider interviews and a random digit dialed telephone survey, were used to track the source and extent of teens' exposure to the intervention. Agency provider data revealed that 40% of the 92 contacted agencies actually conducted violence prevention education, reaching 22% of the target area teens. Approximately one-half of the surveyed teens reported some exposure to the program, with 13% of the teens in target areas reporting participation in interactive educational activities associated with the project. The most common source of exposure was the media campaign. Most teens report a single exposure, usually to the media campaign, although 29% report contact with more than one form of violence prevention education. While the project did not achieve community saturation, the data show that the community-based model of intervention for violence prevention is feasible and effective in reaching teenagers. This research highlights some difficulties in evaluating prevention programs, including reconciling community ownership with project identification, the ethics of curtailing services for control purposes, and factors influencing recall of participation.  相似文献   
78.
79.
In hypoxemic intrauterine growth-retarded fetuses (IUGR) there is a reduction in the incidence of fetal movements and in fetal heart rate variation. A causal relationship with the impairment of fetal oxygenation has been suggested. In 16 IUGR fetuses and in 13 normally grown fetuses maternal hyperoxygenation was applied for 40 min to increase fetal PO2 levels. All IUGR fetuses had abnormal Doppler blood velocity waveforms of the umbilical artery suggesting an impaired uteroplacental exchange. The effect of hyperoxygenation on fetal breathing and body movements and on fetal heart rate was evaluated. In the IUGR fetuses there was a significant increase in fetal breathing and body movements and in heart rate variation during hyperoxygenation as compared to the preceding control period of 40 min. No significant changes in fetal breathing and body movements were found in the normally grown control fetuses. A surprising observation was the increase of the number of heart rate decelerations after discontinuation of the maternal hyperoxygenation. It is concluded that in IUGR fetuses the increase in fetal heart rate variation and the increase in the incidence of breathing and body movements during maternal hyperoxygenation substantiates the relationship between these variables and the oxygenation status of the fetus.  相似文献   
80.
Abstract: For the women with early-stage breast cancer who are candidates for breast conservation therapy, re-excision of the primary tumor bed has commonly been used in patients for several indications. These indications include positive margin or uncertain margin status of the primary excision or residual microcalcifications on postbiopsy mammogram. If the pathology from the re-excision does not confirm negative margin status, mastectomy is generally recommended. This article examines patients who have undergone a second re-excision (i.e., a lumpectomy followed by two re-excisions) who have been treated with breast conservation therapy rather than a mastectomy.
From September 1977 to November 1995, 1,562 patients underwent breast conserving therapy at this institution. Seven hundred forty of these patients underwent a re-excisional biopsy because of positive or uncertain margin status or residual microcalcifications after the first excision. Four patients (0.5%) underwent a second re-excision because of positive or uncertain margin status or residual microcalcifications on mammogram after the first re-excision. The final margin status after the second re-excision of all four patients was negative. The radiation dose was 4,600–5,000 cGy to the whole breast followed by a conedown to bring the total dose to 6,400–6,800 cGy to the primary tumor bed.
Follow-up in the four patients was 13 years, 4 years, 14 months, and 8 months respectively. All four patients are clinically without disease and have not had a locoregional recurrence. Cosmesis was excellent in all four patients. One patient had an adriamycin-induced recall reaction causing a cellulitis, which resolved with antibiotics. There were no other complications.
Highly selected patients may undergo breast-conserving therapy after a second re-excision. Good outcome and cosmesis can be achieved for this small subset of patients with avoidance of a mastectomy.  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