如何对包含多个单词的字符串进行Grep操作，但要逐个准确地检查每个单词？

import re

def grep_multi_word(string, words):
    lines = string.split('\n')  # 将字符串按行拆分成列表
    for line in lines:
        for word in words:
            if re.search(r'\b{}\b'.format(word), line):  # 使用正则表达式进行单词匹配
                print(line)  # 匹配成功则打印该行

# 示例用法
string = """
This is a sample string.
It contains multiple words.
We want to grep each word.
"""

words = ['sample', 'multiple', 'grep']
grep_multi_word(string, words)

This is a sample string.
It contains multiple words.
We want to grep each word.