首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   24223篇
  免费   2274篇
  国内免费   1018篇
耳鼻咽喉   80篇
儿科学   200篇
妇产科学   153篇
基础医学   1840篇
口腔科学   5364篇
临床医学   2046篇
内科学   1928篇
皮肤病学   168篇
神经病学   1633篇
特种医学   545篇
外国民族医学   1篇
外科学   1915篇
综合类   3919篇
一般理论   1篇
预防医学   1066篇
眼科学   226篇
药学   3647篇
  14篇
中国医学   2325篇
肿瘤学   444篇
  2024年   20篇
  2023年   398篇
  2022年   473篇
  2021年   859篇
  2020年   906篇
  2019年   859篇
  2018年   803篇
  2017年   819篇
  2016年   899篇
  2015年   869篇
  2014年   1627篇
  2013年   1630篇
  2012年   1625篇
  2011年   1759篇
  2010年   1371篇
  2009年   1174篇
  2008年   1214篇
  2007年   1304篇
  2006年   1187篇
  2005年   1027篇
  2004年   864篇
  2003年   771篇
  2002年   663篇
  2001年   598篇
  2000年   428篇
  1999年   377篇
  1998年   329篇
  1997年   253篇
  1996年   248篇
  1995年   239篇
  1994年   235篇
  1993年   219篇
  1992年   204篇
  1991年   168篇
  1990年   128篇
  1989年   131篇
  1988年   108篇
  1987年   101篇
  1986年   102篇
  1985年   127篇
  1984年   78篇
  1983年   59篇
  1982年   59篇
  1981年   49篇
  1980年   56篇
  1979年   21篇
  1978年   16篇
  1977年   19篇
  1976年   13篇
  1974年   11篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
93.
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   
94.
95.
96.
Neuropathic pain is a well-recognized chronic pain condition. This can have a significant impact on patients' quality of life. Neuromodulation is defined by the International Neuromodulation Society as ‘the therapeutic alteration of activity in the central or peripheral nervous system either electrically or pharmacologically’. Electrical stimulation can be performed at the motor cortex, deep brain, spinal cord, dorsal root ganglion, peripheral nerve and peripheral nerve field. Pharmacological modulation is achieved by directly infusing drugs to the central nervous system. Although neuromodulation has become increasing popular, it is still currently believed to be underused in treating neuropathic pain. This modality has provided us with a non-pharmacological approach to manage patients with neuropathic pain. Patients should have been assessed by a multidisciplinary team before undergoing neuromodulation. This review highlights the present and future management of patients with chronic intractable pain using neuromodulation.  相似文献   
97.
98.
朱秀琴  李荣香  赵豫鄂 《全科护理》2020,18(12):1495-1497
[目的]探讨专科护理质量指标管理在提高结肠镜诊疗病人肠道准备合格率的作用。[方法]选取2018年3月-2018年6月行结肠镜检查的341例病人为对照组,实施常规肠道准备,2018年7月-2018年10月行结肠镜检查的401例病人为观察组,运用专科护理质量指标进行管理,落实包括建立标准饮食单、规范的泻药服用及方法、分时段健康教育及图片式粪便观察等护理措施及相应质控查检表等相关内容,比较两组病人肠道准备合格率及耐受度。[结果]观察组较对照组病人的肠道准备合格率及耐受度均有明显提高,差异有统计学意义(P<0.01)。[结论]应用专科护理质量指标管理,显著提高了病人肠道准备的合格率及病人的耐受度,体现了标准化肠道准备过程中人性化关怀,同时提升了专科护理质量及护士的专科综合能力。  相似文献   
99.
100.
《Journal of endodontics》2020,46(9):1317-1322
IntroductionThe purpose of this study is to evaluate the amount of residual obturation material of retroinstrumented surgically resected roots using controlled memory files and to evaluate the incidence of adverse treatment outcomes.MethodsThirty maxillary anterior teeth in human cadavers were selected, and nonsurgical root canal treatment was performed on these teeth. A standardized 4-mm osteotomy and a 3-mm root resection with as close to 0° bevel as possible were made on each tooth. A microsurgical diamond tip was used to create a 1- to 2-mm starting point for each retropreparation. A 25/06 and 30/06 VTaper 2H were bent at about 90° angle to mimic the clinical and anatomic restrictions and used to create a retropreparation to a depth of 14 mm. Micro–computed tomography scans were taken and analyzed for volume and percentage of residual obturation material at 5 and 10 mm. In addition, the incidences of instrument separation and crack and ledge formation in the teeth were recorded.ResultsThe median volume of residual obturation at 5 and 10 mm was 0.18 mm3 (interquartile range, 0.36 mm3) and 1.97 mm3 (interquartile range, 1.99 mm3), respectively. The overall incidence of file separation during retropreparation was 13.33% (4/30). Among the cases analyzed with micro–computed tomography, none showed crack or ledge formation.ConclusionsRetroinstrumentation of surgically resected roots using controlled memory files cleans the canal effectively with relatively low adverse treatment outcomes. Although this novel technique is limited in application, it is a safe and effective way to achieve a deep, clean retropreparation.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号