否定关键词和否定商品定位
借助否定关键词和否定商品定向，您可以排除顾客的搜索词、品牌或商品，以免它们触发广告在购物搜索结果或商品详情页中展示。
您可以在“广告活动管理”中或在上传批量文件时创建否定关键词或否定商品定向。添加否定关键词和否定商品或创建批量文件。
否定关键词定向
使用否定关键词，您的广告不会在顾客的搜索词与您的否定关键词匹配时展示。您可以使用否定关键词排除效果不佳的搜索，从而降低广告成本并提高广告支出回报率 (ROAS)。您还可以使用这项功能调整每个广告活动的商品定向和关键词定向，从而了解各种定向的效果。
您不能使用否定关键词来屏蔽 ASIN，但是对于商品推广和品牌推广，您可以通过商品属性定向来实现否定 ASIN 向。了解有关关键词定向和商品定向的更多信息。
对于商品推广，您在选择自动投放或关键词定向策略时会看到“否定关键词定向”这个定向选项；对于品牌推广，您在选择关键词定向策略时会看到该选项。
否定商品定向
使用否定商品定向，您的广告不会在顾客的搜索词与您的否定商品选择匹配时展示。您可以包含希望从定向选项中排除的品牌和商品的否定列表。排除不相关品牌和商品有助于降低您的广告投入产出比 (ACOS)。
对于商品推广，您在选择商品定向时会在广告活动创建工具中看到“否定商品定向”，而对于品牌推广，您在选择商品投放策略时会看到该选项。对于展示型推广活动，您可以在创建广告活动后设置否定投放。
亚马逊官网原文详情：
Negative keyword and product targeting
Negative keyword and negative product targeting allow you to exclude shoppers’ search terms, brands or products from displaying ads in shopping results or detail pages.
You can create a negative keyword or negative product target in the campaign manager, or when uploading a bulk file. Add negative keywords and negative products or create a bulk file.
Negative keyword targeting
Negative keywords prevent your ads from displaying when a shoppers' search terms match your negative keywords. You can use negative keywords to exclude poorly performing searches, reducing your advertising cost and increasing your return on ad spend (ROAS). It can also be used to fine-tune each campaigns' product and keyword targeting to understand individual performance.
You cannot block ASINs using negative keywords, but negative ASIN targeting is available for Sponsored Products and Sponsored Brands using product attribute targeting. Learn more about keyword and product targeting.
Negative keyword targeting is a targeting option in Sponsored Products when selecting automatic targeting or keyword targeting strategy, and in Sponsored Brands when selecting keyword targeting strategy.
Negative product targeting
Negative product targeting prevents your ads from displaying when shoppers’ search terms match your negative product selections. You can include a negative list of brands and products that you would like to exclude from your targeting choices. Excluding irrelevant brands and products can help reduce your advertising cost of sale (ACOS).
Negative product targeting is available in the campaign builder for Sponsored Products when selecting product targeting and for Sponsored Brands when choosing product targeting strategy. For Sponsored Display campaigns, you can set negative targets after the campaign is created.
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