Using the Advanced search found from the Settings link in the right corner of a Google page will help you to compose a more detailed and focused search.
To search for any kind of number range such as years, distances, prices etc., separate the two values in your search by two full stops (no spaces). For example type 25..30 kg to find articles containing the weigh range 25-30 kg or type 2021..2022 to find articles from the years 2021 or 2022.
You can also limit your search to after or before a specific date with after: or before: followed by the date. The date format is YYYY-MM-DD. For example, after:2020/12/31 before:2022/01/01.
You can ask Google to search individual websites or groups of websites sharing a domain. To do this, type site: followed by the web address or domain without any spaces. For example:
Google can search for documents that are available online based on their file format. To do this, type filetype: followed by the file format with no spaces. For example:
Note that newer documents created in Microsoft Office often have an 'x' on the end (e.g. docx instead of doc). You will need to search for these separately.
You can combine this with domain searching. For example, search site:gov.uk filetype:pdf to find UK government reports.