make every possible effort
A dead horse is a living horse doctor, which means the last try.
explain
1. This is a metaphor for knowing that something is hopeless and still hoping to save it. It also refers to making the last attempt.
2. A more commonly used context is: to say that you have prepared for the worst, let it go for a while, even if it is the worst, you will be prepared for it.
source
Song Jiji's "Hongzhi Zen master Guanglu" Volume 1: "if you do, you will go. Xu Er has a sense of happiness. Maybe you will die as a horse doctor."
Example 1: I have thought about what my brother said many times, but my policy is all as the saying goes, dead horse should live horse doctor. ——The third chapter of the future of new China by Liang Qichao in Qing Dynasty
Example 2: with only the last four rounds left in the league, Tiancheng team will encounter such teams as Beijing Baxi and Shijiazhuang Yongchang. In the words of the coach of Tiancheng team, "the hope of relegation is not great, now it can only be a dead horse as a live horse doctor."
Chinese PinYin : sǐ mǎ dāng huó mǎ yī
make every possible effort