全文获取类型
收费全文 | 24675篇 |
免费 | 1318篇 |
国内免费 | 126篇 |
专业分类
耳鼻咽喉 | 246篇 |
儿科学 | 545篇 |
妇产科学 | 545篇 |
基础医学 | 3088篇 |
口腔科学 | 1095篇 |
临床医学 | 1845篇 |
内科学 | 6544篇 |
皮肤病学 | 713篇 |
神经病学 | 1946篇 |
特种医学 | 587篇 |
外科学 | 3529篇 |
综合类 | 126篇 |
一般理论 | 4篇 |
预防医学 | 2149篇 |
眼科学 | 470篇 |
药学 | 1426篇 |
中国医学 | 106篇 |
肿瘤学 | 1155篇 |
出版年
2023年 | 178篇 |
2022年 | 395篇 |
2021年 | 855篇 |
2020年 | 467篇 |
2019年 | 737篇 |
2018年 | 954篇 |
2017年 | 559篇 |
2016年 | 523篇 |
2015年 | 727篇 |
2014年 | 1018篇 |
2013年 | 1249篇 |
2012年 | 1916篇 |
2011年 | 2071篇 |
2010年 | 1076篇 |
2009年 | 1022篇 |
2008年 | 1580篇 |
2007年 | 1695篇 |
2006年 | 1587篇 |
2005年 | 1464篇 |
2004年 | 1341篇 |
2003年 | 1132篇 |
2002年 | 1123篇 |
2001年 | 223篇 |
2000年 | 201篇 |
1999年 | 203篇 |
1998年 | 178篇 |
1997年 | 167篇 |
1996年 | 125篇 |
1995年 | 105篇 |
1994年 | 91篇 |
1993年 | 92篇 |
1992年 | 104篇 |
1991年 | 97篇 |
1990年 | 74篇 |
1989年 | 69篇 |
1988年 | 54篇 |
1987年 | 66篇 |
1986年 | 54篇 |
1985年 | 52篇 |
1984年 | 46篇 |
1983年 | 38篇 |
1982年 | 44篇 |
1981年 | 47篇 |
1980年 | 24篇 |
1979年 | 34篇 |
1978年 | 23篇 |
1974年 | 26篇 |
1973年 | 20篇 |
1972年 | 19篇 |
1971年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Adilson Cunha Ferreira Edward Araujo Júnior Wellington P. Martins João Francisco Jordão Antônio Hélio Oliani Simon E. Meagher 《The journal of maternal-fetal & neonatal medicine》2015,28(14):1706-1710
Objective: To assess the quality of images and video clips of fetal central nervous (CNS) structures obtained by ultrasound and transmitted via tele-ultrasound from Brazil to Australia.Methods: In this cross-sectional study, 15 normal singleton pregnant women between 20 and 26 weeks were selected. Fetal CNS structures were obtained by images and video clips. The exams were transmitted in real-time using a broadband internet and an inexpensive video streaming device. Four blinded examiners evaluated the quality of the exams using the Likert scale. We calculated the mean, standard deviation, mean difference, and p values were obtained from paired t tests.Results: The quality of the original video clips was slightly better than that observed by the transmitted video clips; mean difference considering all observers = 0.23 points. In 47/60 comparisons (78.3%; 95% CI?=?66.4–86.9%) the quality of the video clips were judged to be the same. In 182/240 still images (75.8%; 95% CI?=?70.0–80.8%) the scores of transmitted image were considered the same as the original.Conclusion: We demonstrated that long distance tele-ultrasound transmission of fetal CNS structures using an inexpensive video streaming device provided images of subjective good quality. 相似文献
12.
Joseane Balan Da Silva Gleison Daion Piovezana Bossolani Camila Piva Greicy Brisa Malaquias Dias Jancarlo Gomes Ferreira Diogo Francisco Rossoni 《International journal of environmental health research》2016,26(5-6):578-588
The spatial distribution of enteroparasitosis in an indigenous village from Paraná was evaluated to identify areas of risk for these infections. A cross-sectional study (from November 2010 to June 2011) was performed using Three Faecal Test® and Kato &; Katz method and a questionnaire on housing and hygiene conditions was administered. Local geostatistical analyses were performed to determine the spatial distribution of intestinal parasitic infections. The overall prevalence of enteroparasites was 67.2?% (457/680), and the most prevalent taxa were Ascaris lumbricoides (48.8?%) and Trichuris trichiura (44.7?%). The prevalence of heavy infection by soil-transmitted helminths was 3.6?% and the families lived in houses with an average of 5.1 residents and < 2 bedrooms per household. The average number of species per individual present spatial heterogeneity with the highest values (≥0.8) in areas with high clustering of residences. The visualization of the spatial distribution of intestinal parasites in this indigenous village is an important contribution to determining health risk areas and planning decisions and services. 相似文献
13.
14.
Selcen Yuksel Selim Ayhan Vugar Nabiyev Montse Domingo-Sabat Alba Vila-Casademunt Ibrahim Obeid Francisco Sanchez Perez-Grueso Emre Acaroglu 《The spine journal》2019,19(1):71-78
BACKGROUND CONTEXT
Health-related quality of life (HRQOL) parameters have been shown to be reliable and valid in patients with adult spinal deformity (ASD). Minimum clinically important difference (MCID) has become increasingly important to clinicians in evaluating patients with a threshold of improvement that is clinically relevant.PURPOSE
To calculate MCID and minimum detectable change (MDC) values of total scores of the Core Outcome Measures Index (COMI), Oswestry Disability Index (ODI), Physical Component Summary (PCS), Mental Component Summary (MCS) of the Short Form 36 (SF-36), and Scoliosis Research Society 22R (SRS-22R) in surgically and nonsurgically treated ASD patients who have completed an anchor question at pretreatment and 1-year follow-up.STUDY DESIGN/SETTING
Prospective cohort.PATIENT SAMPLE
Surgical and nonsurgical patients from a multicenter ASD database.OUTCOME MEASURES
Self-reported HRQOL measures (COMI, ODI, SF-36, SRS-22R, and anchor question).METHODS
A total of 185 surgical and 86 nonsurgical patients from a multicenter ASD database who completed pretreatment and 1-year follow-up HRQOL scales and the anchor question at the first year follow-up were included. The anchor question was used to determine MCID for each HRQOL measure. MCIDs were calculated by an anchor-based method using latent class analysis (LCA) and MDCs by a distribution-based method.RESULTS
All differences between means of baseline and first year postoperative total score measures for all scales demonstrated statistically significant improvements in the overall population as well as the surgically treated patients but not in the nonsurgical group. The calculated MDC and MCID values of HRQOL parameters in the entire study population were 1.34 and 2.62 for COMI, 10.65 and 14.31 for ODI, 6.09 and 7.33 for SF-36 PCS, 6.14 and 4.37 for SF-36 MCS, and 0.42 and 0.71 for SRS-22R. The calculated MCID values for surgical and non-surgical treatment groups were 2.76 versus 1.20 for COMI, 14.96 versus 2.45 for ODI, 7.83 versus 2.15 for SF-36 PCS, 5.14 versus 2.03 for SF-36 MCS, and 0.94 versus 0.11 for SRS-22R; the MDC values for surgical and nonsurgical treatment groups were 1.22 versus 1.51 for COMI, 10.27 versus 9.45 for ODI, 5.16 versus 6.77 for SF-36 PCS, 6.05 versus 5.67 for SF-36 MCS, and 0.38 versus 0.43 for SRS-22R.CONCLUSIONS
This study has demonstrated that MCID calculations for the HRQOL scales in ASD using LCA yield values comparable to other studies that had used different methodologies. The most important finding was the significantly different MCIDs for COMI, ODI, SF-36 PCS and SRS-22 in the surgically and nonsurgically treated cohorts. This finding suggests that a universal MCID value, inherent to a specific HRQOL for an entire cohort of ASD may not exist. Use of different MCIDs for surgical and nonsurgical patients may be warranted. 相似文献15.
16.
17.
18.
19.
The degree of metabolic acidosis at birth has been calculated in cord artery and vein samples from 21 term fetuses with cord artery pH less than 7.20. The aim of the study was to compare base deficit values calculated from either Siggaard-Andersen alignment nomogram (BD blood) or the Acid-Base chart (BD extra cellular fluid, BDecf). BDblood was found to be consistently higher in the cord artery as compared with BDecf, 13.2 +/- 3.5 and 9.9 +/- 2.9 mmol/l (Mean +/- SD), respectively. A significant correlation was found between cord artery PCO2 and BDblood whereas BDecf appeared unaffected by PCO2. In cases with cord entanglement BDecf a-v differences were increased to 3.4 +/- 2.3 mmol/l as compared with the small a-v difference noted in acidotic cases without cord entanglement, 1.1 +/- 1.25 mmol/l. It is speculated that with acutely emerging, intermittent asphyxia due to cord compression, a cord artery and vein difference in metabolic acidosis may exist and where the vein captures the basal level and the artery the acute changes. It is concluded that BDecf in both cord artery and vein add valuable information on the mechanisms behind metabolic acidosis. 相似文献
20.
Sergio Barroilhet Adrián Cano-Prous Salvador Cervera-Enguix Maria João Forjaz Francisco Guillén-Grima 《Social psychiatry and psychiatric epidemiology》2009,44(12):1051-1065