## 3 Medical Data Sources  
### Date Source Classification  
Since different categories of medical data contain different medical knowledge, the value of medical big data can be realized only by fusing multiple medical data. For example, [PERSON] et al. [10] proposed the method of fusing multiple data resources to construct knowledge graphs to improve the practical application value of knowledge graphs. Therefore, in this paper, three medical data resources, i.e., medical dictionaries, electronic medical records, and online medical communities, were selected to improve the practical application value of medical knowledge graphs. To be able to effectively enhance the richness of the medical knowledge graph, this paper counted characteristics of data sources selected as medical data sources and formulated a data source selection strategy for the construction of multi-data source medical knowledge graphs. The statistical results and specific characteristics are described as follows. 1. Medical Dictionary  
The medical dictionary mainly includes existing medical dictionary resources, such as the International Classification of Diseases Manual ICD-11, etc. These resources are highly professional and are among the most important data sources of the medical knowledge graph. The International Classification of Disease (ICD) is a manual for classifying diseases published by the World Health Organization (WHO). ICD-11 ([[http://www.medsci.cn/sci/icd-10.asp](http://www.medsci.cn/sci/icd-10.asp)]([http://www.medsci.cn/sci/icd-10.asp](http://www.medsci.cn/sci/icd-10.asp)), accessed on 10 December 2022) is the 11 th revision of ICD, and China has participated in the revision, research, and development process of ICD-11. As shown in Figure 2, some examples of disease codes from the ICD-11 disease classification manual are shown. The first column is the disease name, and the second column is the disease code, which is used to uniquely identify a disease entity. For the first time, the ICD-11 has an all-electronic version, which is easy to use and reduces error rates. A total of 55,000 codes were included in this compilation, far more than the 14,400 codes of the ICD-10. At present, the Chinese translation version provided by the State Hospital Administration is the ICD-11 Concise Code List, with a total of 32,198 entries. Chinese electronic medical record is a record of clinicians' diagnosis and treatment process of patients, mainly including discharge summary and various treatment records, which contains many professional terms in the medical field and a high density of entity vocabulary and is an important data source for constructing medical knowledge graph. Figure 2: The ICD-11 part of the disease coding example. With the support of local hospitals, we obtained 2000 Chinese electronic medical records, and the statistical results are shown in Table 1. The main entity types in the outpatient records and consultation records are body parts, symptoms, and examinations; the main entity types in the medical history records and discharge records are body parts, symptoms, and examinations. 1. Online medical community  
The advantages of online medical communities as an emerging source of medical data are shown below:  
1. There are plentiful medical data resources available for mining;
2. Medical data are originated from the real situation of users;
3. These data have better timeliness and can update faster. In addition, online medical data do not contain private data, are publicly available, and there is a large amount of data. Although the data quality is low compared with the first two types of medical data, it is improving day by day and serve as an important complementary source of data for the medical knowledge graph.