全文获取类型
收费全文 | 8106篇 |
免费 | 398篇 |
国内免费 | 167篇 |
专业分类
耳鼻咽喉 | 128篇 |
儿科学 | 98篇 |
妇产科学 | 59篇 |
基础医学 | 546篇 |
口腔科学 | 154篇 |
临床医学 | 1071篇 |
内科学 | 1028篇 |
皮肤病学 | 26篇 |
神经病学 | 509篇 |
特种医学 | 1518篇 |
外科学 | 958篇 |
综合类 | 1516篇 |
预防医学 | 213篇 |
眼科学 | 92篇 |
药学 | 264篇 |
2篇 | |
中国医学 | 71篇 |
肿瘤学 | 418篇 |
出版年
2024年 | 4篇 |
2023年 | 159篇 |
2022年 | 355篇 |
2021年 | 477篇 |
2020年 | 401篇 |
2019年 | 341篇 |
2018年 | 446篇 |
2017年 | 445篇 |
2016年 | 494篇 |
2015年 | 343篇 |
2014年 | 619篇 |
2013年 | 473篇 |
2012年 | 433篇 |
2011年 | 445篇 |
2010年 | 353篇 |
2009年 | 399篇 |
2008年 | 371篇 |
2007年 | 298篇 |
2006年 | 280篇 |
2005年 | 246篇 |
2004年 | 238篇 |
2003年 | 164篇 |
2002年 | 114篇 |
2001年 | 152篇 |
2000年 | 108篇 |
1999年 | 62篇 |
1998年 | 61篇 |
1997年 | 56篇 |
1996年 | 59篇 |
1995年 | 77篇 |
1994年 | 38篇 |
1993年 | 31篇 |
1992年 | 32篇 |
1991年 | 27篇 |
1990年 | 13篇 |
1989年 | 7篇 |
1988年 | 8篇 |
1987年 | 7篇 |
1986年 | 6篇 |
1985年 | 7篇 |
1984年 | 2篇 |
1983年 | 6篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 4篇 |
1975年 | 2篇 |
排序方式: 共有8671条查询结果,搜索用时 17 毫秒
1.
2.
《European journal of surgical oncology》2022,48(6):1264-1271
BackgroundIn order to avoid excessive treatment of thyroid nodules in the clinic, it is necessary to find a simple and practical analysis method to comprehensively and accurately reflect benign or malignant thyroid nodules. This study aimed to construct and validate a comprehensive and reliable network-based predictive model using a variety of imaging and laboratory criteria for thyroid nodules to stratify the risk of malignancy prior to surgery.MethodsWe retrospectively analyzed data from patients who underwent surgical treatment for thyroid nodules at the Thyroid and Breast Diagnosis and Treatment Center of Weifang Hospital of Traditional Chinese Medicine between January 2018 and December 2020. Binary logical regression analysis was performed to predict whether nodules were malignant or benign. The developmental dataset included 457 patients (January 2018–December 2020). The validation set included separate data points (n = 225, January 2018–December 2020).ResultsIn this study, criteria that showed significant predictive value for malignant nodules included TI-RADS: 4b (p = 0.065); Bethesda IV, Bethesda V, Bethesda VI (P < 0.0001); BRAFV600E mutation (P < 0.0001); Calcitonin>5 pg/ml (p = 0.0037); and FNA-Tg>30 ng/ml (p = 0.0003). A 10-grade risk scoring system was developed. The risk of malignancy risk ranged from 2.06% to 100% and was positively associated with increasing risk grade. The areas under the receiver-operating characteristic curve of the development and validation sets were 0.972 and 0.946, respectively.ConclusionA simple, comprehensive and reliable web-based predictive model was designed using a variety of imaging and laboratory criteria to stratify thyroid nodules by probability of malignancy. 相似文献
3.
4.
Sports Imaging has dramatically increased in the past decade with increasing number of adolescents, young and middle-aged adults participating in non-competitive/hobby sports. Therefore, sports injuries are no longer confined to elite athletes. Furthermore, newer forms of sports such as mountain climbing, pickle ball and curling etc. are gaining popularity. Majority of the injuries in sports medicine are from musculoskeletal trauma. Therefore, it is imperative that the musculoskeletal radiologist becomes familiar with various sports related injury patterns as these are commonly encountered in daily practice. This update aims to briefly encapsulate the major aspects of sports imaging. It includes the imaging manifestations of various types of musculoskeletal injuries on different modalities (commonly US and MRI) and briefly mentions the various image guided interventions, performed both on the sports field and in the hospital setting. 相似文献
5.
6.
目的分析早期剖宫产瘢痕妊娠(CSP)的MRI表现,以提高对这类产科危重症诊断的准确性。方法2017年1月至2019年6月期间,对我院经过手术和病理证实的剖宫产手术后宫腔内瘢痕处早期妊娠的22例患者的MRI资料进行回顾性分析,所有患者均采用MR平扫+增强进行检查,将MRI表现与手术、病理所见进行对照分析。结果单纯孕囊型患者21例,团块型病灶患者1例。瘢痕区呈深V状5例,深U状14例,线或细带状3例。孕囊外壁T2WI可显示低信号线11例,孕囊内壁显示低信号线12例。DWI孕囊呈环状混杂等高信号。增强扫描孕囊呈轻中度环状强化。T2WI、DWI、T1WI增强序列对囊壁内外壁的显示有不同的价值。结论MRI多序列扫描,有助于综合判读孕囊绒毛膜与瘢痕接触的程度,推测孕囊可能的植入部位,对于孕早期CSP诊断具有重要价值。 相似文献
7.
IntroductionCognitive deficits occur in Parkinson's disease (PD). Cardiorespiratory fitness (CRF) is associated with better cognitive performance in aging especially in executive function (EF) and memory. The association between CRF and cognitive performance is understudied in people with PD. Brain structures underlying associations also remains unknown. This cross-sectional study examined the associations between CRF and cognitive performance in PD. We also examined associations between CRF and brain structures impacted in PD. Mediation analysis were conducted to examine whether brain structures impacted in PD mediate putative associations between CRF and cognitive performance.MethodsIndividuals with PD (N = 33) underwent magnetic resonance imaging (MRI), CRF evaluation (estimated VO2max), and neuropsychological assessment. Composite cognitive scores of episodic memory, EF, attention, language, and visuospatial functioning were generated. Structural equation models were constructed to examine whether MRI volume estimates (thalamus and pallidum) mediated associations between CRF and cognitive performance (adjusting for age, education, PD disease duration, sex, MDS-UPDRS motor score, and total intracranial volume).ResultsHigher CRF was associated with better episodic memory (Standardized β = 0.391; p = 0.008), EF (Standardized β = 0.324; p = 0.025), and visuospatial performance (Standardized β = 0.570; p = 0.005). Higher CRF was associated with larger thalamic (Standardized β = 0.722; p = 0.004) and pallidum (Standardized β = 0.635; p = 0.004) volumes. Thalamic volume mediated the association between higher CRF and better EF (Indirect effect = 0.309) and episodic memory (Indirect effect = 0.209) performance (p < 0.05). The pallidum did not significantly mediate associations between CRF and cognitive outcomes.ConclusionThe thalamus plays an important role in the association between CRF and both EF and episodic memory in PD. 相似文献
8.
9.
《Pancreatology》2022,22(5):547-552
Abdominal pain is considered a cardinal feature of acute pancreatitis (AP), and abdominal imaging is only required to diagnose AP when the pain is atypical, or serum enzyme elevation does not match the clinical picture. While painless lipase elevation is being increasingly associated with worse outcomes in various diseases, the diagnostic approach to such elevation is so-far unclear. We thus aimed to learn the impact of pain on the diagnosis of AP.MethodsAll patients presenting to the Mayo Clinic Arizona Hospital emergency department with a serum lipase ≥3x upper limit of normal between April 2016 and January 2020 were prospectively followed. Their charts were reviewed for the nature of pain, serum lipase levels on presentation, abdominal imaging, and whether a diagnosis of AP was made. Chronic pancreatitis was excluded.ResultsAmong 320 patients, 85 (26.5%) had painless lipase elevation. These patients had abdominal imaging less often (56/85, 66%) than in those with abdominal pain (201/235, 83%; p = 0.001). The diagnosis of AP increased overall from 31/63 (49%) without imaging to 198/257 (77%) with imaging (P < 0.001). Imaging increased the diagnosis of AP in patients with painless lipase elevation from 2/29 (7%) without imaging to 16/56 (29%; p = 0.025) among those who were imaged.ConclusionsPainless lipase elevation >3-fold the upper limit of normal is common in emergency department patients. 1/3 to 1/4 of these may have AP. Abdominal imaging increases the diagnosis of AP in patients with painless lipase elevation. Therefore, abdominal imaging in such patients may help detect AP that otherwise eludes diagnosis. 相似文献
10.
《Radiography》2022,28(2):518-523
IntroductionSelection of optimal image acquisition protocols in medical imaging remains a grey area, the superimposed use of the Likert scale in radiological image quality evaluations creates an additional challenge for the statistical analysis of image quality data.Using a simulation study, we have trialled a novel approach to analysing radiological image quality Likert scale data.MethodsA simulation study was undertaken where simulated datasets were generated based on the distribution of Likert scale values according to varying image acquisition protocols from a real dataset. Simulated Likert scale values were pooled in four different ways; the mean, median, mode and the summation of patient Likert scale values of which the total was assigned a categorical Likert scale value. Estimates of bias, MAPE and RMSPE were then calculated for all four pooling approaches to determine which method most accurately represented an expert's opinion.ResultsWhen compared to an expert's opinion, the method of summation and categorisation of Likert scale values was most accurate 49 times out of the 114 (43.0%) tests. The mean 28 times out of 114 (24.6%), the median 23 times out of 114 (20.2%) and the mode 17 times out of 114 (14.9%).ConclusionWe conclude that our method of summation and categorisation of Likert scale values is most often the best representation of the simulated data compared to the expert's opinion.Implications for practiceThere is scope to reproduce this simulation study with multiple observers to reflect clinical reality more accurately with the dynamic nature of multiple observers. This also prompts future investigation into other anatomical areas, to see if the same methods produce similar results. 相似文献