Table 9.

Most frequent words

Rank	Author's keywords	Occurrences	Keywords plus	Occurrences
1	covid-19	677	pneumonia	51
2	machine learning	181	coronavirus	50
3	artificial intelligence	157	prediction	37
4	deep learning	141	china	35
5	coronavirus	134	internet	33
6	sars-cov-2	113	health	32
7	pandemic	81	wuhan	32
8	computed tomography	40	classification	31
9	pneumonia	39	artificial-intelligence	30
10	learning	38	system	30
11	internet of things	37	disease	27
12	telemedicine	36	model	27
13	lung	31	impact	25
14	3d printing	30	outbreak	25
15	big data	30	covid-19	24
16	prediction	26	diagnosis	24
17	classification	24	risk	23
18	diseases	24	management	22
19	intelligence	24	sars	22
20	artificial	22	design	21