全文获取类型
收费全文 | 499408篇 |
免费 | 26507篇 |
国内免费 | 3127篇 |
专业分类
耳鼻咽喉 | 6203篇 |
儿科学 | 14726篇 |
妇产科学 | 11638篇 |
基础医学 | 67097篇 |
口腔科学 | 11705篇 |
临床医学 | 44599篇 |
内科学 | 98291篇 |
皮肤病学 | 8889篇 |
神经病学 | 39669篇 |
特种医学 | 21075篇 |
外国民族医学 | 114篇 |
外科学 | 75781篇 |
综合类 | 8578篇 |
现状与发展 | 1篇 |
一般理论 | 324篇 |
预防医学 | 40415篇 |
眼科学 | 12194篇 |
药学 | 35052篇 |
7篇 | |
中国医学 | 1256篇 |
肿瘤学 | 31428篇 |
出版年
2021年 | 6040篇 |
2020年 | 3715篇 |
2019年 | 5955篇 |
2018年 | 10683篇 |
2017年 | 9409篇 |
2016年 | 8995篇 |
2015年 | 11504篇 |
2014年 | 13877篇 |
2013年 | 16466篇 |
2012年 | 29753篇 |
2011年 | 25433篇 |
2010年 | 13800篇 |
2009年 | 14294篇 |
2008年 | 20267篇 |
2007年 | 21936篇 |
2006年 | 21978篇 |
2005年 | 30407篇 |
2004年 | 32448篇 |
2003年 | 26189篇 |
2002年 | 18628篇 |
2001年 | 10992篇 |
2000年 | 7792篇 |
1999年 | 11974篇 |
1998年 | 4923篇 |
1997年 | 3811篇 |
1996年 | 3139篇 |
1995年 | 2950篇 |
1994年 | 2516篇 |
1992年 | 9994篇 |
1991年 | 9877篇 |
1990年 | 9835篇 |
1989年 | 9380篇 |
1988年 | 8708篇 |
1987年 | 8365篇 |
1986年 | 7960篇 |
1985年 | 7093篇 |
1984年 | 5391篇 |
1983年 | 4497篇 |
1982年 | 2613篇 |
1979年 | 4805篇 |
1978年 | 3185篇 |
1977年 | 2477篇 |
1975年 | 3005篇 |
1974年 | 3654篇 |
1973年 | 3233篇 |
1972年 | 3173篇 |
1971年 | 3075篇 |
1970年 | 2863篇 |
1969年 | 2706篇 |
1968年 | 2432篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
91.
92.
93.
Christos Loizou Göran Laurell Andreas Arvidsson David Lindquist Karin Nylander Katarina Olofsson 《Acta oto-laryngologica》2015,135(10):1058-1064
Conclusion: Recurrent respiratory papillomatosis (RRP) patients with high surgical treatment frequency (≥ 1/year, HF) were significantly younger and had a more widespread laryngeal disease compared to a low frequency treated group (< 1 treatment/year, LF). This study confirms the existence of a clinical RRP group, not primarily related to HPV sub-type, but more care-intensive and in need of more vigilant follow-up. Objectives: RRP is associated with high morbidity due to its influence on breathing and voice. The purpose of this study was to characterize RRP patients in northern Sweden and investigate possible predictor factors affecting therapeutic needs. Method: Patients from the regional referral area (northern Sweden) were categorized for age, disease duration, juvenile or adult onset, profile of disease development, number of surgical sessions in relation to disease duration, laryngeal deposition of papilloma, gender, and HPV sub-types, in order to identify patients with increased need for frequent surgical treatment. Results: The median age of the RRP patients (n = 48) was 44.5 years; 34 (71%) were males and 14 (29%) females, most were infected with HPV 6. Patients with high surgical treatment frequency/year were significantly younger and showed more widespread papillomatous vegetation in the larynx, compared to the low frequency treated group. 相似文献
94.
Contraceptive use is an important strategy for the prevention of unwanted pregnancy and avoidance of induced abortion. Of all the contraception methods, emergency contraceptive (EC) offers the last chance to achieve this. However, few studies have documented the use of EC among young people in Ghana. This study explored knowledge and usage of EC as well as the factors associated with it among University of Cape Coast students. Data were obtained on the knowledge and usage of ECs among University of Cape Coast students in 2013. Logistic regression analysis was used to investigate the association between students’ socio-demographic characteristics and EC knowledge and use. More male students (72 %) than females (59 %) were sexually active. Fifty-seven percent of the respondents had ever heard of EC and 36 % had ever used EC. Although males were more likely to be sexually active, females were more likely to have knowledge of EC use compared to males. The study underscores the need to increase awareness regarding EC among University students in order to offer them the opportunity that EC provides if other forms of contraceptives are missed. 相似文献
95.
Bj?rn Stessel Audrey A. Fiddelers Elbert A. Joosten Daisy M.N. Hoofwijk Hans-Fritz Gramke Wolfgang F.F.A. Buhre 《Medicine》2015,94(39)
Traditionally, major complications and unanticipated admission/readmission rates were used to assess outcome after day surgery. However, in view of the relative absence of major complications the quality of recovery (QOR) should be considered one of the principal endpoints after day surgery. In our study, the level of QOR is defined by a combination of the Global Surgical Recovery (GSR) Index and the Quality of Life (QOL).The aim of this study was to analyze prevalence and predictors of QOR after day surgery on the fourth postoperative day.Elective patients scheduled for day surgery from November 2008 to April 2010 were enrolled in a prospective cohort study. Outcome parameters were measured by using questionnaire packages at 2 time points: 1 week preoperatively and 4 days postoperatively. Primary outcome parameter is the QOR and is defined as good if the GSR index >80% as well as the postoperative QOL is unchanged or improved as compared with baseline. QOR is defined as poor if both the GSR index ≤80% and if the postoperative QOL is decreased as compared with baseline. QOR is defined as intermediate in all other cases. Three logistic regression analyses were performed to determine predictors for poor QOR after day surgery.A total of 1118 patients were included. A good QOR was noted in 17.3% of patients, an intermediate QOR in 34.8%, and a poor QOR in 47.8% 4 days after day surgery. The best predictor for poor QOR after day surgery was type of surgery. Other predictors were younger age, work status, and longer duration of surgery. A history of previous surgery, expected pain (by the patient) and high long-term surgical fear were significant predictors of poor QOR in only 1 of 3 prediction models.The QOR at home 4 days after day surgery was poor in the majority of patients and showed a significant procedure-specific variation. Patients at risk for poor QOR can be identified during the preoperative period based on type of surgery, age, work status, and the duration of the surgery. 相似文献
96.
97.
98.
Miguel A. Sanz Pau Montesinos Haesook T. Kim Guillermo J. Ruiz-Argüelles María S. Undurraga María R. Uriarte Lem Martínez Rafael H. Jacomo Homero Gutiérrez-Aguirre Raul A. M. Melo Rosane Bittencourt Ricardo Pasquini Katia Pagnano Evandro M. Fagundes Edo Vellenga Alexandra Holowiecka Ana J. González-Huerta Pascual Fernández Javier De la Serna Salut Brunet Elena De Lisa José González-Campos José M. Ribera Isabel Krsnik Arnold Ganser Nancy Berliner Raul C. Ribeiro Francesco Lo-Coco Bob L?wenberg Eduardo M. Rego 《Annals of hematology》2015,94(8):1347-1356
99.
Daniel J. Snyder Thomas R. Kroshus Aakash Keswani Evan B. Garden Karl M. Koenig Kevin J. Bozic David S. Jevsevar Jashvant Poeran Calin S. Moucha 《The Journal of arthroplasty》2019,34(4):613-618
Background
Nursing Home Compare (NHC) ratings, created and maintained by Medicare, are used by both hospitals and consumers to aid in the skilled nursing facility (SNF) selection process. To date, no studies have linked NHC ratings to actual episode-based outcomes. The purpose of this study was to evaluate whether NHC ratings are valid predictors of 90-day complications, readmission, and bundle costs for patients discharged to an SNF after primary total joint arthroplasty (TJA).Methods
All SNF-discharged primary TJA cases in 2017 at a multihospital academic health system were queried. Demographic, psychosocial, and clinical variables were manually extracted from the health record. Medicare NHC ratings were then collected for each SNF. For patients in the Medicare bundle, postacute and total bundle cost was extracted from claims.Results
Four hundred eighty-eight patients were discharged to a total of 105 unique SNFs. In multivariate analysis, overall NHC rating was not predictive of 90-day readmission/major complications, >75th percentile postacute cost, or 90-day bundle cost exceeding the target price. SNF health inspection and quality measure ratings were also not predictive of 90-day readmission/major complications or bundle performance. A higher SNF staffing rating was independently associated with a decreased odds for >75th percentile 90-day postacute spend (odds ratio, 0.58; P = .01) and a 90-day bundle cost exceeding the target price (odds ratio = 0.69; P = .02) but was similarly not predictive of 90-day readmission/complications.Conclusion
Results of our study suggest that Medicare's NHC tool is not a useful predictor of 90-day costs, complications, or readmissions for SNFs within our health system. 相似文献100.
Michelle Linda Ferderbar Thomas E. Doyle Reza Samavi David Koff 《Journal l'Association canadienne des radiologistes》2019,70(2):119-124
Several regulatory bodies have agreed that low-dose radiation used in medical imaging is a weak carcinogen that follows a linear, non-threshold model of cancer risk. While avoiding radiation is the best course of action to mitigate risk, computed tomography (CT) scans are often critical for diagnosis. In addition to the as low as reasonably achievable principle, a more concrete method of dose reduction for common CT imaging exams is the use of a diagnostic reference level (DRL). This paper examines Canada's national DRL values from the recent CT survey and compares it to published provincial DRLs as well as the DRLs in the United Kingdom and the United States of America for the 3 most common CT exams: head, chest, and abdomen/pelvis. Canada compares well on the international scale, but it should consider using more electronic dose monitoring solutions to create a culture of dose optimization. 相似文献