全文获取类型
收费全文 | 355530篇 |
免费 | 24099篇 |
国内免费 | 7845篇 |
专业分类
耳鼻咽喉 | 4190篇 |
儿科学 | 9924篇 |
妇产科学 | 6637篇 |
基础医学 | 29948篇 |
口腔科学 | 8065篇 |
临床医学 | 38365篇 |
内科学 | 43336篇 |
皮肤病学 | 9857篇 |
神经病学 | 19751篇 |
特种医学 | 8303篇 |
外国民族医学 | 34篇 |
外科学 | 38845篇 |
综合类 | 52040篇 |
现状与发展 | 12篇 |
一般理论 | 29篇 |
预防医学 | 35476篇 |
眼科学 | 5370篇 |
药学 | 31605篇 |
383篇 | |
中国医学 | 30993篇 |
肿瘤学 | 14311篇 |
出版年
2023年 | 5825篇 |
2022年 | 10080篇 |
2021年 | 13730篇 |
2020年 | 13046篇 |
2019年 | 18708篇 |
2018年 | 16359篇 |
2017年 | 13232篇 |
2016年 | 10810篇 |
2015年 | 10086篇 |
2014年 | 20450篇 |
2013年 | 22452篇 |
2012年 | 18798篇 |
2011年 | 20403篇 |
2010年 | 16423篇 |
2009年 | 15144篇 |
2008年 | 14775篇 |
2007年 | 15300篇 |
2006年 | 13352篇 |
2005年 | 11634篇 |
2004年 | 9524篇 |
2003年 | 8416篇 |
2002年 | 6646篇 |
2001年 | 5994篇 |
2000年 | 4873篇 |
1999年 | 4331篇 |
1998年 | 3513篇 |
1997年 | 3394篇 |
1996年 | 2951篇 |
1995年 | 2794篇 |
1994年 | 2653篇 |
1993年 | 2135篇 |
1992年 | 2163篇 |
1991年 | 1861篇 |
1990年 | 1665篇 |
1989年 | 1499篇 |
1988年 | 1424篇 |
1987年 | 1230篇 |
1985年 | 3879篇 |
1984年 | 4878篇 |
1983年 | 3396篇 |
1982年 | 3866篇 |
1981年 | 3605篇 |
1980年 | 3204篇 |
1979年 | 2954篇 |
1978年 | 2556篇 |
1977年 | 1932篇 |
1976年 | 2176篇 |
1975年 | 1651篇 |
1974年 | 1435篇 |
1973年 | 1286篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
181.
182.
Objectives:To reassess the long-term camouflage effects of resin infiltration (Icon, DMG, Hamburg, Germany) of white spot lesions (WSL) and sound adjacent enamel (SAE) achieved in a previous trial. The null hypothesis was tested that there were no significantly different CIE-L*a*b*-ΔE-values between WSL and SAE areas of assessment after at least 24 months (T24) compared to those at baseline (T0).Materials and Methods:Of twenty subjects who received previous resin infiltration treatment of nteeth = 111 nonrestored, noncavitated postorthodontic WSL after multibracket treatment during a randomized controlled trial and were contacted 20 months after baseline, eight subjects (trial teeth nteeth = 40; m/f ratio 1/7; age range (mean; SD) 12–17 [15.25; 2.12] years); response rate: 40%) were available for follow-up after at least 24 months (T24). CIE-L*a*b* differences between summarized color and lightness values (ΔEWSL/SAE) of WSL and SAE were assessed using a spectrophotometer and compared to baseline data assessed prior to infiltration (T0), and those after 6 (T6), and 12 (T12) months using paired t tests at a significance level of α = 5%.Results:T24 assessments were performed after a mean 33.86 (SD: 8.64; Min: 24; Max: 45) months following T0. Mean (SD) ΔEWSL/SAE units of available teeth were 8.76 (5.33) at baseline; 5.5 (2.75) at T6; 5.2 (2.41) at T12; and 5.57 (2.6) at T24. Comparisons of T6, T12, and T24 with T0 yielded highly significant differences, whereas T6–T24 and T12–T24 differences were found to be not significant.Conclusions:Assimilation of infiltrated WSL to the color of adjacent enamel by resin infiltration is considered to be suitable for the long-term improvement in the esthetic appearance of postorthodontic WSL. 相似文献
183.
M.A. Mashrah T.A. Aldhohrah A. Abdelrehem Moustafa H.M. Al-Sharani A. Alrmali L. Wang 《International journal of oral and maxillofacial surgery》2021,50(1):21-31
Donor site morbidity following radial forearm flap (RFF) harvest remains a controversial issue. The aim of this meta-analysis was to answer the question “Are the range of wrist movements (range of motion, ROM) and hand strength affected after RFF harvesting?” The PubMed, Embase, Scopus, and Cochrane Library electronic databases were systematically searched (to December 2019). Self-controlled studies evaluating hand biomechanics after RFF harvest were included. Weighted mean differences with 95% confidence intervals were calculated using the random-effects model. The outcome variables were ROM, forearm movements, grip, and pinch strengths. Thirteen studies involving a total of 335 patients were included. With the exception of grip strength and supination, which showed statistically significant reductions of about 2.40 kg and 2.86° (P < 0.05), all other ROM, forearm movements, and pinch strengths showed an insignificant difference when the operated hand was compared to the non-operated hand (P > 0.05). Regression analysis showed that the method of donor site closure and size of the donor site defect had an insignificant impact on hand biomechanics. This study confirms the lack of discernible biomechanical morbidity after RFF transfer. The minimal reduction in hand biomechanics after RFF is considered to be clinically negligible. 相似文献
184.
185.
Sina Dami 《World Journal of Clinical Cases》2022,10(26):9207-9218
The coronavirus disease 2019 (COVID-19) has currently caused the mortality of millions of people around the world. Aside from the direct mortality from the COVID-19, the indirect effects of the pandemic have also led to an increase in the mortality rate of other non-COVID patients. Evidence indicates that novel COVID-19 pandemic has caused an inflation in acute cardiovascular mortality, which did not relate to COVID-19 infection. It has in fact increased the risk of death in cardiovascular disease (CVD) patients. For this purpose, it is dramatically inevitable to monitor CVD patients’ vital signs and to detect abnormal events before the occurrence of any critical conditions resulted in death. Internet of things (IoT) and health monitoring sensors have improved the medical care systems by enabling latency-sensitive surveillance and computing of large amounts of patients’ data. The major challenge being faced currently in this problem is its limited scalability and late detection of cardiovascular events in IoT-based computing environments. To this end, this paper proposes a novel framework to early detection of cardiovascular events based on a deep learning architecture in IoT environments. Experimental results showed that the proposed method was able to detect cardiovascular events with better performance (95.30% average sensitivity and 95.94% mean prediction values). 相似文献
186.
187.
188.
189.
《The Foot》2021
BackgroundAs the risk of ankle turn during daily activity is very high, studying ankle kinematics in place is important for ankle sprain prevention. The close-range photogrammetry (CRP) technique is used to measure ankle kinematics during active range of motion (AROM) in place. The purpose of the study was to assess the reliability of CRP to measure ankle kinematics.MethodsTwenty adults were recruited and fourteen retro-reflective targets were mounted on the skin of their right feet. Imaging sensors were self-calibrated using a bundle adjustment technique, and the images were downloaded with Australis photogrammetric software. Three trials were conducted and reliability coefficients were used to assess agreement between them.ResultsReliability was almost perfect and the results show that the intraclass correlation coefficient (ICC) of ankle angle values were (dorsiflexion = 0.96), (plantarflexion = 0.81), (inversion = 0.92), (eversion = 0.95), (internal rotation = 0.92), and (external rotation = 0.78). The overall intraclass correlation coefficient was 0.89 and the standard error of the measurement (SEM) values ranged from (0.37° to 6.18°).ConclusionsThe results indicate that the CRP technique was able to reliably measure ankle kinematics. The results may support and enhance knowledge related to ankle AROM in the clinical arena. 相似文献
190.
Joseph F. Levy Rahul Khairnar Alexander V. Louie Timothy N. Showalter C. Daniel Mullins Mark V. Mishra 《Practical radiation oncology》2019,9(2):e172-e179