a needle in a haystack

释义

落进草垛里的一根针（比喻很难找的东西）；

Finding a needle in a haystack-or identifying anonymous census record
Finding a needle in a haystack: pinpointing significant BGP routing changes in an IP network
Finding a needle in a haystack of reviews:cold start context-based hotel recommender system
Searching for a Needle in a Haystack: Predicting Security Vulnerabilities for Windows Vista.
A needle in a haystack: local one-class optimization
Searching for a Needle in a Haystack: Evaluating Survey Methods for Non-indigenous Plant Species
Magnesium and the control of cell proliferation: looking for a needle in a haystack
Finding a Needle in a Haystack: Direct Determination of Vibrational Signatures in Complex Systems
Looking for a needle in a haystack: inference about individual fitness components in a heterogeneous population
Finding a needle in a haystack using hints and evolutionary computation: the case of evolutionary MasterMind.