Use Google advanced search
Use exact phrases, domains and document formats deliberately, without excluding the evidence you need.
Follow the method ↓
The answer in 30 seconds
Search operators narrow a search. They help when you already know what kind of source is relevant; they cannot make a weak source authoritative.
Start with the subject, then add one justified restriction. Google documents quotes, site: and filetype:; write the value immediately after the colon.
Examples to adapt
Try the subject with a publisher domain, then add PDF only if the format is useful.
Remove the quotes or check the wording against the original title before tightening the query further.
Portal workshop
Build a purposeful search query
Describe your task, add useful constraints and read their effects. Preparation stays on your device without being saved by the portal. The Search on Google button sends the query to Google; do not enter confidential information.
Follow the method
- 1Write the subject first
For example, begin with “air quality annual report”. Check the ordinary results before deciding what needs narrowing.
- 2Use quotes selectively
Quote a phrase only when its exact wording is known, such as a document title. An uncertain quotation can hide the right page.
- 3Choose a domain for a reason
Add site:ecologie.gouv.fr when you specifically need that publisher. A domain restriction searches that site, not every competent organisation.
- 4Choose a format if needed
Add filetype:pdf to seek a downloadable document. A PDF may be outdated or unofficial; inspect its author and publication date.
- 5Relax constraints and verify
Remove a restriction when results become unhelpful. Open the original document and check whether its scope answers the question.
A closer look
Change one constraint at a time
These queries illustrate syntax without promising particular results. Compare the returned pages after adding one filter at each step.
| Need | Example query | If results are too narrow |
|---|---|---|
| Explore a topic | urban biodiversity | Try a related term |
| Find a phrase | "urban biodiversity" | Remove the quotation marks |
| Target an organisation | biodiversity site:cnrs.fr | Consider other organisations |
| Find a particular format | biodiversity site:cnrs.fr filetype:pdf | Remove the format filter |
Google documents quotation marks, site: and filetype:. Filters restrict results; they do not verify document dates, quality or search completeness.
Do no results mean that the document does not exist?
That conclusion is unsupported. Remove a constraint, try alternative wording and browse the target website. Keep the query so that an unsuccessful search can be distinguished from established absence.
Supporting documentation : Google — Affiner les recherches · Consulted on 2026-10-15. Examples and calculations are illustrative.
A checklist to keep
Use these checks to record what you found. The grid supports a decision; it does not make one for you.
| Check | What to examine | Action |
|---|---|---|
| Phrase | Exact wording known | Quote only that phrase |
| Domain | Relevant publisher | Use site: without a space |
| Format | A downloadable file is needed | Try filetype:pdf |
| Coverage | Useful pages disappear | Remove one restriction |
Read the checklist directly in the table.
What to check
A result count is not a quality measure.
A document format does not establish authority.
Keep the query and the document date separately.
Common questions
Do I need every operator at once?
No. Add one only to solve a specific problem and compare the results.
Does site: guarantee an official answer?
It limits a domain. You still need to identify the page, its author and its applicability.
Sources and documentation
Documentation consulted on . Examples are illustrative; interfaces and results may change.