全文获取类型
收费全文 | 33566篇 |
免费 | 1995篇 |
国内免费 | 613篇 |
专业分类
耳鼻咽喉 | 291篇 |
儿科学 | 1379篇 |
妇产科学 | 1596篇 |
基础医学 | 3583篇 |
口腔科学 | 650篇 |
临床医学 | 2741篇 |
内科学 | 4581篇 |
皮肤病学 | 494篇 |
神经病学 | 3453篇 |
特种医学 | 767篇 |
外国民族医学 | 3篇 |
外科学 | 3170篇 |
综合类 | 4039篇 |
现状与发展 | 5篇 |
预防医学 | 3516篇 |
眼科学 | 136篇 |
药学 | 3560篇 |
39篇 | |
中国医学 | 1039篇 |
肿瘤学 | 1132篇 |
出版年
2023年 | 365篇 |
2022年 | 772篇 |
2021年 | 1191篇 |
2020年 | 1042篇 |
2019年 | 896篇 |
2018年 | 887篇 |
2017年 | 1019篇 |
2016年 | 996篇 |
2015年 | 942篇 |
2014年 | 1772篇 |
2013年 | 2186篇 |
2012年 | 1632篇 |
2011年 | 1942篇 |
2010年 | 1557篇 |
2009年 | 1506篇 |
2008年 | 1555篇 |
2007年 | 1524篇 |
2006年 | 1427篇 |
2005年 | 1233篇 |
2004年 | 1037篇 |
2003年 | 975篇 |
2002年 | 808篇 |
2001年 | 704篇 |
2000年 | 658篇 |
1999年 | 557篇 |
1998年 | 482篇 |
1997年 | 506篇 |
1996年 | 470篇 |
1995年 | 407篇 |
1994年 | 409篇 |
1993年 | 366篇 |
1992年 | 383篇 |
1991年 | 360篇 |
1990年 | 368篇 |
1989年 | 294篇 |
1988年 | 244篇 |
1987年 | 222篇 |
1986年 | 254篇 |
1985年 | 324篇 |
1984年 | 292篇 |
1983年 | 184篇 |
1982年 | 247篇 |
1981年 | 199篇 |
1980年 | 166篇 |
1979年 | 167篇 |
1978年 | 140篇 |
1977年 | 107篇 |
1976年 | 88篇 |
1975年 | 72篇 |
1974年 | 62篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
目的探究组织气氛在护士吞咽障碍知识水平与护理行为之间的中介效应。方法2019年6-7月,便利抽样法选取15个省市33所医院及医疗机构神经科、康复科具有吞咽障碍护理经验的231名护士为研究对象采用脑卒中吞咽障碍知识水平问卷、脑卒中吞咽障碍护理行为问卷及团队创新气氛量表对其进行调查。结果护士吞咽障碍知识水平总分为(56.69±13.50)分、护理行为得分为(140.65土32.02)分、组织气氛得分为(157.63±26.56)分。组织气氛与吞咽障碍知识水平(r=0.49,P<0.01)、护理行为(r=0.50,P<0.01)均呈正相关。组织气氛在知识水平和护理行为之间起中介作用,中介效应占总效应的83.18%。结论组织气氛在护士吞咽障碍知识水平与护理行为之间起中介作用,临床管理者可在提升护士吞咽障碍知识水平的基础上,通过提高组织气氛水平推进其护理行为。 相似文献
3.
4.
《Diagnostic and interventional imaging》2020,101(9):555-564
PurposeThe purpose of this study was to determine whether computed tomography (CT)-based machine learning of radiomics features could help distinguish autoimmune pancreatitis (AIP) from pancreatic ductal adenocarcinoma (PDAC).Materials and MethodsEighty-nine patients with AIP (65 men, 24 women; mean age, 59.7 ± 13.9 [SD] years; range: 21–83 years) and 93 patients with PDAC (68 men, 25 women; mean age, 60.1 ± 12.3 [SD] years; range: 36–86 years) were retrospectively included. All patients had dedicated dual-phase pancreatic protocol CT between 2004 and 2018. Thin-slice images (0.75/0.5 mm thickness/increment) were compared with thick-slices images (3 or 5 mm thickness/increment). Pancreatic regions involved by PDAC or AIP (areas of enlargement, altered enhancement, effacement of pancreatic duct) as well as uninvolved parenchyma were segmented as three-dimensional volumes. Four hundred and thirty-one radiomics features were extracted and a random forest was used to distinguish AIP from PDAC. CT data of 60 AIP and 60 PDAC patients were used for training and those of 29 AIP and 33 PDAC independent patients were used for testing.ResultsThe pancreas was diffusely involved in 37 (37/89; 41.6%) patients with AIP and not diffusely in 52 (52/89; 58.4%) patients. Using machine learning, 95.2% (59/62; 95% confidence interval [CI]: 89.8–100%), 83.9% (52:67; 95% CI: 74.7–93.0%) and 77.4% (48/62; 95% CI: 67.0–87.8%) of the 62 test patients were correctly classified as either having PDAC or AIP with thin-slice venous phase, thin-slice arterial phase, and thick-slice venous phase CT, respectively. Three of the 29 patients with AIP (3/29; 10.3%) were incorrectly classified as having PDAC but all 33 patients with PDAC (33/33; 100%) were correctly classified with thin-slice venous phase with 89.7% sensitivity (26/29; 95% CI: 78.6–100%) and 100% specificity (33/33; 95% CI: 93–100%) for the diagnosis of AIP, 95.2% accuracy (59/62; 95% CI: 89.8–100%) and area under the curve of 0.975 (95% CI: 0.936–1.0).ConclusionsRadiomic features help differentiate AIP from PDAC with an overall accuracy of 95.2%. 相似文献
5.
6.
目的:探讨甲状旁腺激素(PTH)对大鼠牵张成骨(DO)过程中ONC、OPN、C-FOS、COL1、VEGF、RUNX2、ALP基因表达的影响。方法30只雄性大鼠制备大鼠下颌骨DO模型。随机分5组,每组6只。第1组(只有牵张无PTH),术后8周取材,应用HE染色及微CT检测,以确定成骨情况。第2组(有牵张无PTH),第3组(有牵张有PTH),第4组(无牵张有PTH),第5组(对照组:无牵张无PTH)。2、3、4组及对照组术后1周取材,RT-PCR测定ONC、OPN、C-FOS、COL1、VEGF、RUNX2、ALP基因的表达。结果第1组,新骨形成,骨质充满牵张区,骨质连续,大鼠建模成功。RT-PCR检测结果显示,2、3、4组与对照组比较,OPN、COL1、RUNX2、ALP基因表达有明显提高(P<0.05),其中第3组最为明显。ONC、C-FOS、VEGF基因2、3、4组与对照组比较差异无统计学意义(P>0.05)。结论 PTH在 DO 过程中,间歇性给以 PTH的作用只有在牵张期发挥作用,其对 OPN、COL1、RUNX2、ALP基因表达能够获得理想的协同作用。 相似文献
7.
8.
9.
W. Do T. Elzerman R. de Bree A. Rosenberg T. Forouzanfar E.M. Van Cann 《International journal of oral and maxillofacial surgery》2021,50(5):591-597
The aim of this study was to analyse the effect of body mass index (BMI), both low and high values, on the perioperative complication rate in patients with oral squamous cell carcinoma (OSCC). The medical records of 259 patients operated between 2014 and 2017 for OSCC were reviewed. Univariate and multivariate analyses were performed. Sixty of the 259 patients developed 87 complications. Low or high BMI was not associated with the perioperative complication rate. A longer operating time and increased blood loss were associated with a higher perioperative complication rate and higher Clavien–Dindo grade. Low BMI, American Society of Anesthesiologists score 2 and 3, a longer operating time, and increased blood loss were associated with a longer hospital stay. Low BMI was associated with a longer hospital stay. Neither low nor high BMI was associated with the perioperative complication rate. A longer operating time and increased blood loss were associated with a higher perioperative complication rate and higher Clavien–Dindo grade. 相似文献
10.
Sex estimation by various forensic anthropology approaches is a crucial factor for identification of human skeletal remains. However, inexpensive, uncomplicated and reliable methods are still required, especially in a remote crime scene and a high crime incidence area. Here, we examined 13 sacral parameters from 78 independent skeletons derived from deceases found in Central Thailand (male, n = 46; female, n = 32) using simple standard anthropometric techniques for sex allocation. Discriminant analysis exhibited that anterior-posterior diameter of S1 vertebra corpus (APS) is the most accurate sacral parameter for sex determination in our study with 82.1% of correct discrimination rate. The accuracy could be improved up to 97.4% when additional three sacral variables including the length of sacrum measured from the medial anterior-superior sacral promontory to the medial anterior-inferior S5 vertebra (ASL), alar index (ALI), and the maximum anterior breadth of sacrum measured across sacral alar (ABS) were computed together with APS. These encourage the use of sacral morphometrics for sex assessment of human sacrum remains in Central Thailand. However, further investigation with broadening sacral morphometric data across the country might provide a promising sex determination equation from a sacral skeleton for Thai population. 相似文献