Research

Publish Year

Type

Factors

Level

Li Aifang [75]

2012

CT

① (−2) ② (−1) ⑦ (+1) ⑥ (+1)

M

Zhu Zhenhua [76]

2001

CR

① (−1) ② (−1) ⑥ (+1)

VL

Hou Zhixia [77]

2010

RCT

① (−2) ② (−1) ⑥ (+1)

VL