Numerous attempts to stop the leak have failed or not yielded the desired results.

我们尝试了很多方法，但这些措施不是失败了，就是没有达到预期效果。

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In spite of that, scientists are unable to effectively make this variety survive as micro-propagation and vegetative means have not yielded the desired result.

尽管如此，科学家们还是无法有效地使这个品种幸存下来，因为微型繁殖和营养方法并没有取得预期的效果。

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But it has been luckier than vesta-and almost every other asteroid-in avoiding collisions, and has thus not yielded a huge crop of meteorites for Earth-bound scientists to examine.

但在避免碰撞方面，它比灶神星要幸运得多——几乎比其它任何小行星也都幸运，因此它没有产生可供地球科学家研究的大量陨石。

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Some analysts said he overpaid, and the deal has not yielded big returns.

FORBES: Magazine Article

But Millennium's gene databases have not yielded a single marketed drug, either for Millennium or any of the partners who ponied up big bucks.

FORBES: Biotech Battle Scars

The second cause of disillusion is a sense that Mr Sarkozy's reforms, which he promised would boost growth, jobs and pay, have not yielded results.

ECONOMIST: France